1 /* 2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. Oracle designates this 7 * particular file as subject to the "Classpath" exception as provided 8 * by Oracle in the LICENSE file that accompanied this code. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 */ 24 25 /* 26 * This file is available under and governed by the GNU General Public 27 * License version 2 only, as published by the Free Software Foundation. 28 * However, the following notice accompanied the original version of this 29 * file: 30 * 31 * Written by Doug Lea with assistance from members of JCP JSR-166 32 * Expert Group and released to the public domain, as explained at 33 * http://creativecommons.org/publicdomain/zero/1.0/ 34 */ 35 36 package java.util.concurrent; 37 38 import java.io.ObjectStreamField; 39 import java.io.Serializable; 40 import java.lang.reflect.ParameterizedType; 41 import java.lang.reflect.Type; 42 import java.util.AbstractMap; 43 import java.util.Arrays; 44 import java.util.Collection; 45 import java.util.Enumeration; 46 import java.util.HashMap; 47 import java.util.Hashtable; 48 import java.util.Iterator; 49 import java.util.Map; 50 import java.util.NoSuchElementException; 51 import java.util.Objects; 52 import java.util.Set; 53 import java.util.Spliterator; 54 import java.util.concurrent.atomic.AtomicReference; 55 import java.util.concurrent.locks.LockSupport; 56 import java.util.concurrent.locks.ReentrantLock; 57 import java.util.function.BiConsumer; 58 import java.util.function.BiFunction; 59 import java.util.function.Consumer; 60 import java.util.function.DoubleBinaryOperator; 61 import java.util.function.Function; 62 import java.util.function.IntBinaryOperator; 63 import java.util.function.LongBinaryOperator; 64 import java.util.function.Predicate; 65 import java.util.function.ToDoubleBiFunction; 66 import java.util.function.ToDoubleFunction; 67 import java.util.function.ToIntBiFunction; 68 import java.util.function.ToIntFunction; 69 import java.util.function.ToLongBiFunction; 70 import java.util.function.ToLongFunction; 71 import java.util.stream.Stream; 72 import jdk.internal.misc.Unsafe; 73 import jdk.internal.util.ArraysSupport; 74 import jdk.internal.vm.annotation.AOTRuntimeSetup; 75 import jdk.internal.vm.annotation.AOTSafeClassInitializer; 76 import jdk.internal.vm.annotation.Stable; 77 78 /** 79 * A hash table supporting full concurrency of retrievals and 80 * high expected concurrency for updates. This class obeys the 81 * same functional specification as {@link java.util.Hashtable}, and 82 * includes versions of methods corresponding to each method of 83 * {@code Hashtable}. However, even though all operations are 84 * thread-safe, retrieval operations do <em>not</em> entail locking, 85 * and there is <em>not</em> any support for locking the entire table 86 * in a way that prevents all access. This class is fully 87 * interoperable with {@code Hashtable} in programs that rely on its 88 * thread safety but not on its synchronization details. 89 * 90 * <p>Retrieval operations (including {@code get}) generally do not 91 * block, so may overlap with update operations (including {@code put} 92 * and {@code remove}). Retrievals reflect the results of the most 93 * recently <em>completed</em> update operations holding upon their 94 * onset. (More formally, an update operation for a given key bears a 95 * <em>happens-before</em> relation with any (non-null) retrieval for 96 * that key reporting the updated value.) For aggregate operations 97 * such as {@code putAll} and {@code clear}, concurrent retrievals may 98 * reflect insertion or removal of only some entries. Similarly, 99 * Iterators, Spliterators and Enumerations return elements reflecting the 100 * state of the hash table at some point at or since the creation of the 101 * iterator/enumeration. They do <em>not</em> throw {@link 102 * java.util.ConcurrentModificationException ConcurrentModificationException}. 103 * However, iterators are designed to be used by only one thread at a time. 104 * Bear in mind that the results of aggregate status methods including 105 * {@code size}, {@code isEmpty}, and {@code containsValue} are typically 106 * useful only when a map is not undergoing concurrent updates in other threads. 107 * Otherwise the results of these methods reflect transient states 108 * that may be adequate for monitoring or estimation purposes, but not 109 * for program control. 110 * 111 * <p>The table is dynamically expanded when there are too many 112 * collisions (i.e., keys that have distinct hash codes but fall into 113 * the same slot modulo the table size), with the expected average 114 * effect of maintaining roughly two bins per mapping (corresponding 115 * to a 0.75 load factor threshold for resizing). There may be much 116 * variance around this average as mappings are added and removed, but 117 * overall, this maintains a commonly accepted time/space tradeoff for 118 * hash tables. However, resizing this or any other kind of hash 119 * table may be a relatively slow operation. When possible, it is a 120 * good idea to provide a size estimate as an optional {@code 121 * initialCapacity} constructor argument. An additional optional 122 * {@code loadFactor} constructor argument provides a further means of 123 * customizing initial table capacity by specifying the table density 124 * to be used in calculating the amount of space to allocate for the 125 * given number of elements. Also, for compatibility with previous 126 * versions of this class, constructors may optionally specify an 127 * expected {@code concurrencyLevel} as an additional hint for 128 * internal sizing. Note that using many keys with exactly the same 129 * {@code hashCode()} is a sure way to slow down performance of any 130 * hash table. To ameliorate impact, when keys are {@link Comparable}, 131 * this class may use comparison order among keys to help break ties. 132 * 133 * <p>A {@link Set} projection of a ConcurrentHashMap may be created 134 * (using {@link #newKeySet()} or {@link #newKeySet(int)}), or viewed 135 * (using {@link #keySet(Object)} when only keys are of interest, and the 136 * mapped values are (perhaps transiently) not used or all take the 137 * same mapping value. 138 * 139 * <p>A ConcurrentHashMap can be used as a scalable frequency map (a 140 * form of histogram or multiset) by using {@link 141 * java.util.concurrent.atomic.LongAdder} values and initializing via 142 * {@link #computeIfAbsent computeIfAbsent}. For example, to add a count 143 * to a {@code ConcurrentHashMap<String,LongAdder> freqs}, you can use 144 * {@code freqs.computeIfAbsent(key, k -> new LongAdder()).increment();} 145 * 146 * <p>This class and its views and iterators implement all of the 147 * <em>optional</em> methods of the {@link Map} and {@link Iterator} 148 * interfaces. 149 * 150 * <p>Like {@link Hashtable} but unlike {@link HashMap}, this class 151 * does <em>not</em> allow {@code null} to be used as a key or value. 152 * 153 * <p id="Bulk">ConcurrentHashMaps support a set of sequential and parallel bulk 154 * operations that, unlike most {@link Stream} methods, are designed 155 * to be safely, and often sensibly, applied even with maps that are 156 * being concurrently updated by other threads; for example, when 157 * computing a snapshot summary of the values in a shared registry. 158 * There are three kinds of operation, each with four forms, accepting 159 * functions with keys, values, entries, and (key, value) pairs as 160 * arguments and/or return values. Because the elements of a 161 * ConcurrentHashMap are not ordered in any particular way, and may be 162 * processed in different orders in different parallel executions, the 163 * correctness of supplied functions should not depend on any 164 * ordering, or on any other objects or values that may transiently 165 * change while computation is in progress; and except for forEach 166 * actions, should ideally be side-effect-free. Bulk operations on 167 * {@link Map.Entry} objects do not support method {@code setValue}. 168 * 169 * <ul> 170 * <li>forEach: Performs a given action on each element. 171 * A variant form applies a given transformation on each element 172 * before performing the action. 173 * 174 * <li>search: Returns the first available non-null result of 175 * applying a given function on each element; skipping further 176 * search when a result is found. 177 * 178 * <li>reduce: Accumulates each element. The supplied reduction 179 * function cannot rely on ordering (more formally, it should be 180 * both associative and commutative). There are five variants: 181 * 182 * <ul> 183 * 184 * <li>Plain reductions. (There is not a form of this method for 185 * (key, value) function arguments since there is no corresponding 186 * return type.) 187 * 188 * <li>Mapped reductions that accumulate the results of a given 189 * function applied to each element. 190 * 191 * <li>Reductions to scalar doubles, longs, and ints, using a 192 * given basis value. 193 * 194 * </ul> 195 * </ul> 196 * 197 * <p>These bulk operations accept a {@code parallelismThreshold} 198 * argument. Methods proceed sequentially if the current map size is 199 * estimated to be less than the given threshold. Using a value of 200 * {@code Long.MAX_VALUE} suppresses all parallelism. Using a value 201 * of {@code 1} results in maximal parallelism by partitioning into 202 * enough subtasks to fully utilize the {@link 203 * ForkJoinPool#commonPool()} that is used for all parallel 204 * computations. Normally, you would initially choose one of these 205 * extreme values, and then measure performance of using in-between 206 * values that trade off overhead versus throughput. 207 * 208 * <p>The concurrency properties of bulk operations follow 209 * from those of ConcurrentHashMap: Any non-null result returned 210 * from {@code get(key)} and related access methods bears a 211 * happens-before relation with the associated insertion or 212 * update. The result of any bulk operation reflects the 213 * composition of these per-element relations (but is not 214 * necessarily atomic with respect to the map as a whole unless it 215 * is somehow known to be quiescent). Conversely, because keys 216 * and values in the map are never null, null serves as a reliable 217 * atomic indicator of the current lack of any result. To 218 * maintain this property, null serves as an implicit basis for 219 * all non-scalar reduction operations. For the double, long, and 220 * int versions, the basis should be one that, when combined with 221 * any other value, returns that other value (more formally, it 222 * should be the identity element for the reduction). Most common 223 * reductions have these properties; for example, computing a sum 224 * with basis 0 or a minimum with basis MAX_VALUE. 225 * 226 * <p>Search and transformation functions provided as arguments 227 * should similarly return null to indicate the lack of any result 228 * (in which case it is not used). In the case of mapped 229 * reductions, this also enables transformations to serve as 230 * filters, returning null (or, in the case of primitive 231 * specializations, the identity basis) if the element should not 232 * be combined. You can create compound transformations and 233 * filterings by composing them yourself under this "null means 234 * there is nothing there now" rule before using them in search or 235 * reduce operations. 236 * 237 * <p>Methods accepting and/or returning Entry arguments maintain 238 * key-value associations. They may be useful for example when 239 * finding the key for the greatest value. Note that "plain" Entry 240 * arguments can be supplied using {@code new 241 * AbstractMap.SimpleEntry(k,v)}. 242 * 243 * <p>Bulk operations may complete abruptly, throwing an 244 * exception encountered in the application of a supplied 245 * function. Bear in mind when handling such exceptions that other 246 * concurrently executing functions could also have thrown 247 * exceptions, or would have done so if the first exception had 248 * not occurred. 249 * 250 * <p>Speedups for parallel compared to sequential forms are common 251 * but not guaranteed. Parallel operations involving brief functions 252 * on small maps may execute more slowly than sequential forms if the 253 * underlying work to parallelize the computation is more expensive 254 * than the computation itself. Similarly, parallelization may not 255 * lead to much actual parallelism if all processors are busy 256 * performing unrelated tasks. 257 * 258 * <p>All arguments to all task methods must be non-null. 259 * 260 * <p>This class is a member of the 261 * <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework"> 262 * Java Collections Framework</a>. 263 * 264 * @since 1.5 265 * @author Doug Lea 266 * @param <K> the type of keys maintained by this map 267 * @param <V> the type of mapped values 268 */ 269 @AOTSafeClassInitializer 270 public class ConcurrentHashMap<K,V> extends AbstractMap<K,V> 271 implements ConcurrentMap<K,V>, Serializable { 272 private static final long serialVersionUID = 7249069246763182397L; 273 274 /* 275 * Overview: 276 * 277 * The primary design goal of this hash table is to maintain 278 * concurrent readability (typically method get(), but also 279 * iterators and related methods) while minimizing update 280 * contention. Secondary goals are to keep space consumption about 281 * the same or better than java.util.HashMap, and to support high 282 * initial insertion rates on an empty table by many threads. 283 * 284 * This map usually acts as a binned (bucketed) hash table. Each 285 * key-value mapping is held in a Node. Most nodes are instances 286 * of the basic Node class with hash, key, value, and next 287 * fields. However, various subclasses exist: TreeNodes are 288 * arranged in balanced trees, not lists. TreeBins hold the roots 289 * of sets of TreeNodes. ForwardingNodes are placed at the heads 290 * of bins during resizing. ReservationNodes are used as 291 * placeholders while establishing values in computeIfAbsent and 292 * related methods. The types TreeBin, ForwardingNode, and 293 * ReservationNode do not hold normal user keys, values, or 294 * hashes, and are readily distinguishable during search etc 295 * because they have negative hash fields and null key and value 296 * fields. (These special nodes are either uncommon or transient, 297 * so the impact of carrying around some unused fields is 298 * insignificant.) 299 * 300 * The table is lazily initialized to a power-of-two size upon the 301 * first insertion. Each bin in the table normally contains a 302 * list of Nodes (most often, the list has only zero or one Node). 303 * Table accesses require volatile/atomic reads, writes, and 304 * CASes. Because there is no other way to arrange this without 305 * adding further indirections, we use intrinsics 306 * (jdk.internal.misc.Unsafe) operations. 307 * 308 * We use the top (sign) bit of Node hash fields for control 309 * purposes -- it is available anyway because of addressing 310 * constraints. Nodes with negative hash fields are specially 311 * handled or ignored in map methods. 312 * 313 * Insertion (via put or its variants) of the first node in an 314 * empty bin is performed by just CASing it to the bin. This is 315 * by far the most common case for put operations under most 316 * key/hash distributions. Other update operations (insert, 317 * delete, and replace) require locks. We do not want to waste 318 * the space required to associate a distinct lock object with 319 * each bin, so instead use the first node of a bin list itself as 320 * a lock. Locking support for these locks relies on builtin 321 * "synchronized" monitors. 322 * 323 * Using the first node of a list as a lock does not by itself 324 * suffice though: When a node is locked, any update must first 325 * validate that it is still the first node after locking it, and 326 * retry if not. Because new nodes are always appended to lists, 327 * once a node is first in a bin, it remains first until deleted 328 * or the bin becomes invalidated (upon resizing). 329 * 330 * The main disadvantage of per-bin locks is that other update 331 * operations on other nodes in a bin list protected by the same 332 * lock can stall, for example when user equals() or mapping 333 * functions take a long time. However, statistically, under 334 * random hash codes, this is not a common problem. Ideally, the 335 * frequency of nodes in bins follows a Poisson distribution 336 * (http://en.wikipedia.org/wiki/Poisson_distribution) with a 337 * parameter of about 0.5 on average, given the resizing threshold 338 * of 0.75, although with a large variance because of resizing 339 * granularity. Ignoring variance, the expected occurrences of 340 * list size k are (exp(-0.5) * pow(0.5, k) / factorial(k)). The 341 * first values are: 342 * 343 * 0: 0.60653066 344 * 1: 0.30326533 345 * 2: 0.07581633 346 * 3: 0.01263606 347 * 4: 0.00157952 348 * 5: 0.00015795 349 * 6: 0.00001316 350 * 7: 0.00000094 351 * 8: 0.00000006 352 * more: less than 1 in ten million 353 * 354 * Lock contention probability for two threads accessing distinct 355 * elements is roughly 1 / (8 * #elements) under random hashes. 356 * 357 * Actual hash code distributions encountered in practice 358 * sometimes deviate significantly from uniform randomness. This 359 * includes the case when N > (1<<30), so some keys MUST collide. 360 * Similarly for dumb or hostile usages in which multiple keys are 361 * designed to have identical hash codes or ones that differs only 362 * in masked-out high bits. So we use a secondary strategy that 363 * applies when the number of nodes in a bin exceeds a 364 * threshold. These TreeBins use a balanced tree to hold nodes (a 365 * specialized form of red-black trees), bounding search time to 366 * O(log N). Each search step in a TreeBin is at least twice as 367 * slow as in a regular list, but given that N cannot exceed 368 * (1<<64) (before running out of addresses) this bounds search 369 * steps, lock hold times, etc, to reasonable constants (roughly 370 * 100 nodes inspected per operation worst case) so long as keys 371 * are Comparable (which is very common -- String, Long, etc). 372 * TreeBin nodes (TreeNodes) also maintain the same "next" 373 * traversal pointers as regular nodes, so can be traversed in 374 * iterators in the same way. 375 * 376 * The table is resized when occupancy exceeds a percentage 377 * threshold (nominally, 0.75, but see below). Any thread 378 * noticing an overfull bin may assist in resizing after the 379 * initiating thread allocates and sets up the replacement array. 380 * However, rather than stalling, these other threads may proceed 381 * with insertions etc. The use of TreeBins shields us from the 382 * worst case effects of overfilling while resizes are in 383 * progress. Resizing proceeds by transferring bins, one by one, 384 * from the table to the next table. However, threads claim small 385 * blocks of indices to transfer (via field transferIndex) before 386 * doing so, reducing contention. A generation stamp in field 387 * sizeCtl ensures that resizings do not overlap. Because we are 388 * using power-of-two expansion, the elements from each bin must 389 * either stay at same index, or move with a power of two 390 * offset. We eliminate unnecessary node creation by catching 391 * cases where old nodes can be reused because their next fields 392 * won't change. On average, only about one-sixth of them need 393 * cloning when a table doubles. The nodes they replace will be 394 * garbage collectible as soon as they are no longer referenced by 395 * any reader thread that may be in the midst of concurrently 396 * traversing table. Upon transfer, the old table bin contains 397 * only a special forwarding node (with hash field "MOVED") that 398 * contains the next table as its key. On encountering a 399 * forwarding node, access and update operations restart, using 400 * the new table. 401 * 402 * Each bin transfer requires its bin lock, which can stall 403 * waiting for locks while resizing. However, because other 404 * threads can join in and help resize rather than contend for 405 * locks, average aggregate waits become shorter as resizing 406 * progresses. The transfer operation must also ensure that all 407 * accessible bins in both the old and new table are usable by any 408 * traversal. This is arranged in part by proceeding from the 409 * last bin (table.length - 1) up towards the first. Upon seeing 410 * a forwarding node, traversals (see class Traverser) arrange to 411 * move to the new table without revisiting nodes. To ensure that 412 * no intervening nodes are skipped even when moved out of order, 413 * a stack (see class TableStack) is created on first encounter of 414 * a forwarding node during a traversal, to maintain its place if 415 * later processing the current table. The need for these 416 * save/restore mechanics is relatively rare, but when one 417 * forwarding node is encountered, typically many more will be. 418 * So Traversers use a simple caching scheme to avoid creating so 419 * many new TableStack nodes. (Thanks to Peter Levart for 420 * suggesting use of a stack here.) 421 * 422 * The traversal scheme also applies to partial traversals of 423 * ranges of bins (via an alternate Traverser constructor) 424 * to support partitioned aggregate operations. Also, read-only 425 * operations give up if ever forwarded to a null table, which 426 * provides support for shutdown-style clearing, which is also not 427 * currently implemented. 428 * 429 * Lazy table initialization minimizes footprint until first use, 430 * and also avoids resizings when the first operation is from a 431 * putAll, constructor with map argument, or deserialization. 432 * These cases attempt to override the initial capacity settings, 433 * but harmlessly fail to take effect in cases of races. 434 * 435 * The element count is maintained using a specialization of 436 * LongAdder. We need to incorporate a specialization rather than 437 * just use a LongAdder in order to access implicit 438 * contention-sensing that leads to creation of multiple 439 * CounterCells. The counter mechanics avoid contention on 440 * updates but can encounter cache thrashing if read too 441 * frequently during concurrent access. To avoid reading so often, 442 * resizing under contention is attempted only upon adding to a 443 * bin already holding two or more nodes. Under uniform hash 444 * distributions, the probability of this occurring at threshold 445 * is around 13%, meaning that only about 1 in 8 puts check 446 * threshold (and after resizing, many fewer do so). 447 * 448 * TreeBins use a special form of comparison for search and 449 * related operations (which is the main reason we cannot use 450 * existing collections such as TreeMaps). TreeBins contain 451 * Comparable elements, but may contain others, as well as 452 * elements that are Comparable but not necessarily Comparable for 453 * the same T, so we cannot invoke compareTo among them. To handle 454 * this, the tree is ordered primarily by hash value, then by 455 * Comparable.compareTo order if applicable. On lookup at a node, 456 * if elements are not comparable or compare as 0 then both left 457 * and right children may need to be searched in the case of tied 458 * hash values. (This corresponds to the full list search that 459 * would be necessary if all elements were non-Comparable and had 460 * tied hashes.) On insertion, to keep a total ordering (or as 461 * close as is required here) across rebalancings, we compare 462 * classes and identityHashCodes as tie-breakers. The red-black 463 * balancing code is updated from pre-jdk-collections 464 * (http://gee.cs.oswego.edu/dl/classes/collections/RBCell.java) 465 * based in turn on Cormen, Leiserson, and Rivest "Introduction to 466 * Algorithms" (CLR). 467 * 468 * TreeBins also require an additional locking mechanism. While 469 * list traversal is always possible by readers even during 470 * updates, tree traversal is not, mainly because of tree-rotations 471 * that may change the root node and/or its linkages. TreeBins 472 * include a simple read-write lock mechanism parasitic on the 473 * main bin-synchronization strategy: Structural adjustments 474 * associated with an insertion or removal are already bin-locked 475 * (and so cannot conflict with other writers) but must wait for 476 * ongoing readers to finish. Since there can be only one such 477 * waiter, we use a simple scheme using a single "waiter" field to 478 * block writers. However, readers need never block. If the root 479 * lock is held, they proceed along the slow traversal path (via 480 * next-pointers) until the lock becomes available or the list is 481 * exhausted, whichever comes first. These cases are not fast, but 482 * maximize aggregate expected throughput. 483 * 484 * Maintaining API and serialization compatibility with previous 485 * versions of this class introduces several oddities. Mainly: We 486 * leave untouched but unused constructor arguments referring to 487 * concurrencyLevel. We accept a loadFactor constructor argument, 488 * but apply it only to initial table capacity (which is the only 489 * time that we can guarantee to honor it.) We also declare an 490 * unused "Segment" class that is instantiated in minimal form 491 * only when serializing. 492 * 493 * Also, solely for compatibility with previous versions of this 494 * class, it extends AbstractMap, even though all of its methods 495 * are overridden, so it is just useless baggage. 496 * 497 * This file is organized to make things a little easier to follow 498 * while reading than they might otherwise: First the main static 499 * declarations and utilities, then fields, then main public 500 * methods (with a few factorings of multiple public methods into 501 * internal ones), then sizing methods, trees, traversers, and 502 * bulk operations. 503 */ 504 505 /* ---------------- Constants -------------- */ 506 507 /** 508 * The largest possible table capacity. This value must be 509 * exactly 1<<30 to stay within Java array allocation and indexing 510 * bounds for power of two table sizes, and is further required 511 * because the top two bits of 32bit hash fields are used for 512 * control purposes. 513 */ 514 private static final int MAXIMUM_CAPACITY = 1 << 30; 515 516 /** 517 * The default initial table capacity. Must be a power of 2 518 * (i.e., at least 1) and at most MAXIMUM_CAPACITY. 519 */ 520 private static final int DEFAULT_CAPACITY = 16; 521 522 /** 523 * The largest possible (non-power of two) array size. 524 * Needed by toArray and related methods. 525 */ 526 static final int MAX_ARRAY_SIZE = ArraysSupport.SOFT_MAX_ARRAY_LENGTH; 527 528 /** 529 * The default concurrency level for this table. Unused but 530 * defined for compatibility with previous versions of this class. 531 */ 532 private static final int DEFAULT_CONCURRENCY_LEVEL = 16; 533 534 /** 535 * The load factor for this table. Overrides of this value in 536 * constructors affect only the initial table capacity. The 537 * actual floating point value isn't normally used -- it is 538 * simpler to use expressions such as {@code n - (n >>> 2)} for 539 * the associated resizing threshold. 540 */ 541 private static final float LOAD_FACTOR = 0.75f; 542 543 /** 544 * The bin count threshold for using a tree rather than list for a 545 * bin. Bins are converted to trees when adding an element to a 546 * bin with at least this many nodes. The value must be greater 547 * than 2, and should be at least 8 to mesh with assumptions in 548 * tree removal about conversion back to plain bins upon 549 * shrinkage. 550 */ 551 static final int TREEIFY_THRESHOLD = 8; 552 553 /** 554 * The bin count threshold for untreeifying a (split) bin during a 555 * resize operation. Should be less than TREEIFY_THRESHOLD, and at 556 * most 6 to mesh with shrinkage detection under removal. 557 */ 558 static final int UNTREEIFY_THRESHOLD = 6; 559 560 /** 561 * The smallest table capacity for which bins may be treeified. 562 * (Otherwise the table is resized if too many nodes in a bin.) 563 * The value should be at least 4 * TREEIFY_THRESHOLD to avoid 564 * conflicts between resizing and treeification thresholds. 565 */ 566 static final int MIN_TREEIFY_CAPACITY = 64; 567 568 /** 569 * Minimum number of rebinnings per transfer step. Ranges are 570 * subdivided to allow multiple resizer threads. This value 571 * serves as a lower bound to avoid resizers encountering 572 * excessive memory contention. The value should be at least 573 * DEFAULT_CAPACITY. 574 */ 575 private static final int MIN_TRANSFER_STRIDE = 16; 576 577 /** 578 * The number of bits used for generation stamp in sizeCtl. 579 * Must be at least 6 for 32bit arrays. 580 */ 581 private static final int RESIZE_STAMP_BITS = 16; 582 583 /** 584 * The maximum number of threads that can help resize. 585 * Must fit in 32 - RESIZE_STAMP_BITS bits. 586 */ 587 private static final int MAX_RESIZERS = (1 << (32 - RESIZE_STAMP_BITS)) - 1; 588 589 /** 590 * The bit shift for recording size stamp in sizeCtl. 591 */ 592 private static final int RESIZE_STAMP_SHIFT = 32 - RESIZE_STAMP_BITS; 593 594 /* 595 * Encodings for Node hash fields. See above for explanation. 596 */ 597 static final int MOVED = -1; // hash for forwarding nodes 598 static final int TREEBIN = -2; // hash for roots of trees 599 static final int RESERVED = -3; // hash for transient reservations 600 static final int HASH_BITS = 0x7fffffff; // usable bits of normal node hash 601 602 /** Number of CPUS, to place bounds on some sizings */ 603 static @Stable int NCPU; 604 605 static { 606 runtimeSetup(); 607 } 608 609 @AOTRuntimeSetup 610 private static void runtimeSetup() { 611 NCPU = Runtime.getRuntime().availableProcessors(); 612 } 613 614 /** 615 * Serialized pseudo-fields, provided only for jdk7 compatibility. 616 * @serialField segments Segment[] 617 * The segments, each of which is a specialized hash table. 618 * @serialField segmentMask int 619 * Mask value for indexing into segments. The upper bits of a 620 * key's hash code are used to choose the segment. 621 * @serialField segmentShift int 622 * Shift value for indexing within segments. 623 */ 624 private static final ObjectStreamField[] serialPersistentFields = { 625 new ObjectStreamField("segments", Segment[].class), 626 new ObjectStreamField("segmentMask", Integer.TYPE), 627 new ObjectStreamField("segmentShift", Integer.TYPE), 628 }; 629 630 /* ---------------- Nodes -------------- */ 631 632 /** 633 * Key-value entry. This class is never exported out as a 634 * user-mutable Map.Entry (i.e., one supporting setValue; see 635 * MapEntry below), but can be used for read-only traversals used 636 * in bulk tasks. Subclasses of Node with a negative hash field 637 * are special, and contain null keys and values (but are never 638 * exported). Otherwise, keys and vals are never null. 639 */ 640 static class Node<K,V> implements Map.Entry<K,V> { 641 final int hash; 642 final K key; 643 volatile V val; 644 volatile Node<K,V> next; 645 646 Node(int hash, K key, V val) { 647 this.hash = hash; 648 this.key = key; 649 this.val = val; 650 } 651 652 Node(int hash, K key, V val, Node<K,V> next) { 653 this(hash, key, val); 654 this.next = next; 655 } 656 657 public final K getKey() { return key; } 658 public final V getValue() { return val; } 659 public final int hashCode() { return key.hashCode() ^ val.hashCode(); } 660 public final String toString() { 661 return Helpers.mapEntryToString(key, val); 662 } 663 public final V setValue(V value) { 664 throw new UnsupportedOperationException(); 665 } 666 667 public final boolean equals(Object o) { 668 Object k, v, u; Map.Entry<?,?> e; 669 return ((o instanceof Map.Entry) && 670 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 671 (v = e.getValue()) != null && 672 (Objects.equals(k, key)) && 673 v.equals(val)); 674 } 675 676 /** 677 * Virtualized support for map.get(); overridden in subclasses. 678 */ 679 Node<K,V> find(int h, Object k) { 680 Node<K,V> e = this; 681 if (k != null) { 682 do { 683 K ek; 684 if (e.hash == h && 685 (ek = e.key) != null && Objects.equals(k, ek)) 686 return e; 687 } while ((e = e.next) != null); 688 } 689 return null; 690 } 691 } 692 693 /* ---------------- Static utilities -------------- */ 694 695 /** 696 * Spreads (XORs) higher bits of hash to lower and also forces top 697 * bit to 0. Because the table uses power-of-two masking, sets of 698 * hashes that vary only in bits above the current mask will 699 * always collide. (Among known examples are sets of Float keys 700 * holding consecutive whole numbers in small tables.) So we 701 * apply a transform that spreads the impact of higher bits 702 * downward. There is a tradeoff between speed, utility, and 703 * quality of bit-spreading. Because many common sets of hashes 704 * are already reasonably distributed (so don't benefit from 705 * spreading), and because we use trees to handle large sets of 706 * collisions in bins, we just XOR some shifted bits in the 707 * cheapest possible way to reduce systematic lossage, as well as 708 * to incorporate impact of the highest bits that would otherwise 709 * never be used in index calculations because of table bounds. 710 */ 711 static final int spread(int h) { 712 return (h ^ (h >>> 16)) & HASH_BITS; 713 } 714 715 /** 716 * Returns a power of two table size for the given desired capacity. 717 * See Hackers Delight, sec 3.2 718 */ 719 private static final int tableSizeFor(int c) { 720 int n = -1 >>> Integer.numberOfLeadingZeros(c - 1); 721 return (n < 0) ? 1 : (n >= MAXIMUM_CAPACITY) ? MAXIMUM_CAPACITY : n + 1; 722 } 723 724 /** 725 * Returns x's Class if it is of the form "class C implements 726 * Comparable<C>", else null. 727 */ 728 static Class<?> comparableClassFor(Object x) { 729 if (x instanceof Comparable) { 730 Class<?> c; Type[] ts, as; ParameterizedType p; 731 if ((c = x.getClass()) == String.class) // bypass checks 732 return c; 733 if ((ts = c.getGenericInterfaces()) != null) { 734 for (Type t : ts) { 735 if ((t instanceof ParameterizedType) && 736 ((p = (ParameterizedType)t).getRawType() == 737 Comparable.class) && 738 (as = p.getActualTypeArguments()) != null && 739 as.length == 1 && as[0] == c) // type arg is c 740 return c; 741 } 742 } 743 } 744 return null; 745 } 746 747 /** 748 * Returns k.compareTo(x) if x matches kc (k's screened comparable 749 * class), else 0. 750 */ 751 @SuppressWarnings("unchecked") // for cast to Comparable 752 static int compareComparables(Class<?> kc, Object k, Object x) { 753 return (x == null || x.getClass() != kc ? 0 : 754 ((Comparable)k).compareTo(x)); 755 } 756 757 /* ---------------- Table element access -------------- */ 758 759 /* 760 * Atomic access methods are used for table elements as well as 761 * elements of in-progress next table while resizing. All uses of 762 * the tab arguments must be null checked by callers. All callers 763 * also paranoically precheck that tab's length is not zero (or an 764 * equivalent check), thus ensuring that any index argument taking 765 * the form of a hash value anded with (length - 1) is a valid 766 * index. Note that, to be correct wrt arbitrary concurrency 767 * errors by users, these checks must operate on local variables, 768 * which accounts for some odd-looking inline assignments below. 769 * Note that calls to setTabAt always occur within locked regions, 770 * and so require only release ordering. 771 */ 772 773 @SuppressWarnings("unchecked") 774 static final <K,V> Node<K,V> tabAt(Node<K,V>[] tab, int i) { 775 return (Node<K,V>)U.getReferenceAcquire(tab, ((long)i << ASHIFT) + ABASE); 776 } 777 778 static final <K,V> boolean casTabAt(Node<K,V>[] tab, int i, 779 Node<K,V> c, Node<K,V> v) { 780 return U.compareAndSetReference(tab, ((long)i << ASHIFT) + ABASE, c, v); 781 } 782 783 static final <K,V> void setTabAt(Node<K,V>[] tab, int i, Node<K,V> v) { 784 U.putReferenceRelease(tab, ((long)i << ASHIFT) + ABASE, v); 785 } 786 787 /* ---------------- Fields -------------- */ 788 789 /** 790 * The array of bins. Lazily initialized upon first insertion. 791 * Size is always a power of two. Accessed directly by iterators. 792 */ 793 transient volatile Node<K,V>[] table; 794 795 /** 796 * The next table to use; non-null only while resizing. 797 */ 798 private transient volatile Node<K,V>[] nextTable; 799 800 /** 801 * Base counter value, used mainly when there is no contention, 802 * but also as a fallback during table initialization 803 * races. Updated via CAS. 804 */ 805 private transient volatile long baseCount; 806 807 /** 808 * Table initialization and resizing control. When negative, the 809 * table is being initialized or resized: -1 for initialization, 810 * else -(1 + the number of active resizing threads). Otherwise, 811 * when table is null, holds the initial table size to use upon 812 * creation, or 0 for default. After initialization, holds the 813 * next element count value upon which to resize the table. 814 */ 815 private transient volatile int sizeCtl; 816 817 /** 818 * The next table index (plus one) to split while resizing. 819 */ 820 private transient volatile int transferIndex; 821 822 /** 823 * Spinlock (locked via CAS) used when resizing and/or creating CounterCells. 824 */ 825 private transient volatile int cellsBusy; 826 827 /** 828 * Table of counter cells. When non-null, size is a power of 2. 829 */ 830 private transient volatile CounterCell[] counterCells; 831 832 // views 833 private transient KeySetView<K,V> keySet; 834 private transient ValuesView<K,V> values; 835 private transient EntrySetView<K,V> entrySet; 836 837 838 /* ---------------- Public operations -------------- */ 839 840 /** 841 * Creates a new, empty map with the default initial table size (16). 842 */ 843 public ConcurrentHashMap() { 844 } 845 846 /** 847 * Creates a new, empty map with an initial table size 848 * accommodating the specified number of elements without the need 849 * to dynamically resize. 850 * 851 * @param initialCapacity The implementation performs internal 852 * sizing to accommodate this many elements. 853 * @throws IllegalArgumentException if the initial capacity of 854 * elements is negative 855 */ 856 public ConcurrentHashMap(int initialCapacity) { 857 this(initialCapacity, LOAD_FACTOR, 1); 858 } 859 860 /** 861 * Creates a new map with the same mappings as the given map. 862 * 863 * @param m the map 864 */ 865 @SuppressWarnings("this-escape") 866 public ConcurrentHashMap(Map<? extends K, ? extends V> m) { 867 this(m.size()); 868 putAll(m); 869 } 870 871 /** 872 * Creates a new, empty map with an initial table size based on 873 * the given number of elements ({@code initialCapacity}) and 874 * initial table density ({@code loadFactor}). 875 * 876 * @param initialCapacity the initial capacity. The implementation 877 * performs internal sizing to accommodate this many elements, 878 * given the specified load factor. 879 * @param loadFactor the load factor (table density) for 880 * establishing the initial table size 881 * @throws IllegalArgumentException if the initial capacity of 882 * elements is negative or the load factor is nonpositive 883 * 884 * @since 1.6 885 */ 886 public ConcurrentHashMap(int initialCapacity, float loadFactor) { 887 this(initialCapacity, loadFactor, 1); 888 } 889 890 /** 891 * Creates a new, empty map with an initial table size based on 892 * the given number of elements ({@code initialCapacity}), initial 893 * table density ({@code loadFactor}), and number of concurrently 894 * updating threads ({@code concurrencyLevel}). 895 * 896 * @param initialCapacity the initial capacity. The implementation 897 * performs internal sizing to accommodate this many elements, 898 * given the specified load factor. 899 * @param loadFactor the load factor (table density) for 900 * establishing the initial table size 901 * @param concurrencyLevel the estimated number of concurrently 902 * updating threads. The implementation may use this value as 903 * a sizing hint. 904 * @throws IllegalArgumentException if the initial capacity is 905 * negative or the load factor or concurrencyLevel are 906 * nonpositive 907 */ 908 public ConcurrentHashMap(int initialCapacity, 909 float loadFactor, int concurrencyLevel) { 910 if (!(loadFactor > 0.0f) || initialCapacity < 0 || concurrencyLevel <= 0) 911 throw new IllegalArgumentException(); 912 if (initialCapacity < concurrencyLevel) // Use at least as many bins 913 initialCapacity = concurrencyLevel; // as estimated threads 914 long size = (long)(1.0 + (long)initialCapacity / loadFactor); 915 int cap = (size >= (long)MAXIMUM_CAPACITY) ? 916 MAXIMUM_CAPACITY : tableSizeFor((int)size); 917 this.sizeCtl = cap; 918 } 919 920 // Original (since JDK1.2) Map methods 921 922 /** 923 * {@inheritDoc} 924 */ 925 public int size() { 926 long n = sumCount(); 927 return ((n < 0L) ? 0 : 928 (n > (long)Integer.MAX_VALUE) ? Integer.MAX_VALUE : 929 (int)n); 930 } 931 932 /** 933 * {@inheritDoc} 934 */ 935 public boolean isEmpty() { 936 return sumCount() <= 0L; // ignore transient negative values 937 } 938 939 /** 940 * Returns the value to which the specified key is mapped, 941 * or {@code null} if this map contains no mapping for the key. 942 * 943 * <p>More formally, if this map contains a mapping from a key 944 * {@code k} to a value {@code v} such that {@code key.equals(k)}, 945 * then this method returns {@code v}; otherwise it returns 946 * {@code null}. (There can be at most one such mapping.) 947 * 948 * @throws NullPointerException if the specified key is null 949 */ 950 public V get(Object key) { 951 Node<K,V>[] tab; Node<K,V> e, p; int n, eh; K ek; 952 int h = spread(key.hashCode()); 953 if ((tab = table) != null && (n = tab.length) > 0 && 954 (e = tabAt(tab, (n - 1) & h)) != null) { 955 if ((eh = e.hash) == h) { 956 if ((ek = e.key) != null && Objects.equals(key, ek)) 957 return e.val; 958 } 959 else if (eh < 0) 960 return (p = e.find(h, key)) != null ? p.val : null; 961 while ((e = e.next) != null) { 962 if (e.hash == h && 963 ((ek = e.key) != null && Objects.equals(key, ek))) 964 return e.val; 965 } 966 } 967 return null; 968 } 969 970 /** 971 * Tests if the specified object is a key in this table. 972 * 973 * @param key possible key 974 * @return {@code true} if and only if the specified object 975 * is a key in this table, as determined by the 976 * {@code equals} method; {@code false} otherwise 977 * @throws NullPointerException if the specified key is null 978 */ 979 public boolean containsKey(Object key) { 980 return get(key) != null; 981 } 982 983 /** 984 * Returns {@code true} if this map maps one or more keys to the 985 * specified value. Note: This method may require a full traversal 986 * of the map, and is much slower than method {@code containsKey}. 987 * 988 * @param value value whose presence in this map is to be tested 989 * @return {@code true} if this map maps one or more keys to the 990 * specified value 991 * @throws NullPointerException if the specified value is null 992 */ 993 public boolean containsValue(Object value) { 994 if (value == null) 995 throw new NullPointerException(); 996 Node<K,V>[] t; 997 if ((t = table) != null) { 998 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 999 for (Node<K,V> p; (p = it.advance()) != null; ) { 1000 V v; 1001 if ((v = p.val) != null && Objects.equals(value, v)) 1002 return true; 1003 } 1004 } 1005 return false; 1006 } 1007 1008 /** 1009 * Maps the specified key to the specified value in this table. 1010 * Neither the key nor the value can be null. 1011 * 1012 * <p>The value can be retrieved by calling the {@code get} method 1013 * with a key that is equal to the original key. 1014 * 1015 * @param key key with which the specified value is to be associated 1016 * @param value value to be associated with the specified key 1017 * @return the previous value associated with {@code key}, or 1018 * {@code null} if there was no mapping for {@code key} 1019 * @throws NullPointerException if the specified key or value is null 1020 */ 1021 public V put(K key, V value) { 1022 return putVal(key, value, false); 1023 } 1024 1025 /** Implementation for put and putIfAbsent */ 1026 final V putVal(K key, V value, boolean onlyIfAbsent) { 1027 if (key == null || value == null) throw new NullPointerException(); 1028 int hash = spread(key.hashCode()); 1029 int binCount = 0; 1030 for (Node<K,V>[] tab = table;;) { 1031 Node<K,V> f; int n, i, fh; K fk; V fv; 1032 if (tab == null || (n = tab.length) == 0) 1033 tab = initTable(); 1034 else if ((f = tabAt(tab, i = (n - 1) & hash)) == null) { 1035 if (casTabAt(tab, i, null, new Node<K,V>(hash, key, value))) 1036 break; // no lock when adding to empty bin 1037 } 1038 else if ((fh = f.hash) == MOVED) 1039 tab = helpTransfer(tab, f); 1040 else if (onlyIfAbsent // check first node without acquiring lock 1041 && fh == hash 1042 && (fk = f.key) != null && Objects.equals(key, fk) 1043 && (fv = f.val) != null) 1044 return fv; 1045 else { 1046 V oldVal = null; 1047 synchronized (f) { 1048 if (tabAt(tab, i) == f) { 1049 if (fh >= 0) { 1050 binCount = 1; 1051 for (Node<K,V> e = f;; ++binCount) { 1052 K ek; 1053 if (e.hash == hash && 1054 (ek = e.key) != null && Objects.equals(key, ek)) { 1055 oldVal = e.val; 1056 if (!onlyIfAbsent) 1057 e.val = value; 1058 break; 1059 } 1060 Node<K,V> pred = e; 1061 if ((e = e.next) == null) { 1062 pred.next = new Node<K,V>(hash, key, value); 1063 break; 1064 } 1065 } 1066 } 1067 else if (f instanceof TreeBin) { 1068 Node<K,V> p; 1069 binCount = 2; 1070 if ((p = ((TreeBin<K,V>)f).putTreeVal(hash, key, 1071 value)) != null) { 1072 oldVal = p.val; 1073 if (!onlyIfAbsent) 1074 p.val = value; 1075 } 1076 } 1077 else if (f instanceof ReservationNode) 1078 throw new IllegalStateException("Recursive update"); 1079 } 1080 } 1081 if (binCount != 0) { 1082 if (binCount >= TREEIFY_THRESHOLD) 1083 treeifyBin(tab, i); 1084 if (oldVal != null) 1085 return oldVal; 1086 break; 1087 } 1088 } 1089 } 1090 addCount(1L, binCount); 1091 return null; 1092 } 1093 1094 /** 1095 * Copies all of the mappings from the specified map to this one. 1096 * These mappings replace any mappings that this map had for any of the 1097 * keys currently in the specified map. 1098 * 1099 * @param m mappings to be stored in this map 1100 */ 1101 public void putAll(Map<? extends K, ? extends V> m) { 1102 if (table != null) { 1103 tryPresize(size() + m.size()); 1104 } 1105 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) 1106 putVal(e.getKey(), e.getValue(), false); 1107 } 1108 1109 /** 1110 * Removes the key (and its corresponding value) from this map. 1111 * This method does nothing if the key is not in the map. 1112 * 1113 * @param key the key that needs to be removed 1114 * @return the previous value associated with {@code key}, or 1115 * {@code null} if there was no mapping for {@code key} 1116 * @throws NullPointerException if the specified key is null 1117 */ 1118 public V remove(Object key) { 1119 return replaceNode(key, null, null); 1120 } 1121 1122 /** 1123 * Implementation for the four public remove/replace methods: 1124 * Replaces node value with v, conditional upon match of cv if 1125 * non-null. If resulting value is null, delete. 1126 */ 1127 final V replaceNode(Object key, V value, Object cv) { 1128 int hash = spread(key.hashCode()); 1129 for (Node<K,V>[] tab = table;;) { 1130 Node<K,V> f; int n, i, fh; 1131 if (tab == null || (n = tab.length) == 0 || 1132 (f = tabAt(tab, i = (n - 1) & hash)) == null) 1133 break; 1134 else if ((fh = f.hash) == MOVED) 1135 tab = helpTransfer(tab, f); 1136 else { 1137 V oldVal = null; 1138 boolean validated = false; 1139 synchronized (f) { 1140 if (tabAt(tab, i) == f) { 1141 if (fh >= 0) { 1142 validated = true; 1143 for (Node<K,V> e = f, pred = null;;) { 1144 K ek; 1145 if (e.hash == hash && 1146 ((ek = e.key) != null && Objects.equals(key, ek))) { 1147 V ev = e.val; 1148 if (cv == null || 1149 (ev != null && Objects.equals(cv, ev))) { 1150 oldVal = ev; 1151 if (value != null) 1152 e.val = value; 1153 else if (pred != null) 1154 pred.next = e.next; 1155 else 1156 setTabAt(tab, i, e.next); 1157 } 1158 break; 1159 } 1160 pred = e; 1161 if ((e = e.next) == null) 1162 break; 1163 } 1164 } 1165 else if (f instanceof TreeBin) { 1166 validated = true; 1167 TreeBin<K,V> t = (TreeBin<K,V>)f; 1168 TreeNode<K,V> r, p; 1169 if ((r = t.root) != null && 1170 (p = r.findTreeNode(hash, key, null)) != null) { 1171 V pv = p.val; 1172 if (cv == null || 1173 (pv != null && Objects.equals(cv, pv))) { 1174 oldVal = pv; 1175 if (value != null) 1176 p.val = value; 1177 else if (t.removeTreeNode(p)) 1178 setTabAt(tab, i, untreeify(t.first)); 1179 } 1180 } 1181 } 1182 else if (f instanceof ReservationNode) 1183 throw new IllegalStateException("Recursive update"); 1184 } 1185 } 1186 if (validated) { 1187 if (oldVal != null) { 1188 if (value == null) 1189 addCount(-1L, -1); 1190 return oldVal; 1191 } 1192 break; 1193 } 1194 } 1195 } 1196 return null; 1197 } 1198 1199 /** 1200 * Removes all of the mappings from this map. 1201 */ 1202 public void clear() { 1203 long delta = 0L; // negative number of deletions 1204 int i = 0; 1205 Node<K,V>[] tab = table; 1206 while (tab != null && i < tab.length) { 1207 int fh; 1208 Node<K,V> f = tabAt(tab, i); 1209 if (f == null) 1210 ++i; 1211 else if ((fh = f.hash) == MOVED) { 1212 tab = helpTransfer(tab, f); 1213 i = 0; // restart 1214 } 1215 else { 1216 synchronized (f) { 1217 if (tabAt(tab, i) == f) { 1218 Node<K,V> p = (fh >= 0 ? f : 1219 (f instanceof TreeBin) ? 1220 ((TreeBin<K,V>)f).first : null); 1221 while (p != null) { 1222 --delta; 1223 p = p.next; 1224 } 1225 setTabAt(tab, i++, null); 1226 } 1227 } 1228 } 1229 } 1230 if (delta != 0L) 1231 addCount(delta, -1); 1232 } 1233 1234 /** 1235 * Returns a {@link Set} view of the keys contained in this map. 1236 * The set is backed by the map, so changes to the map are 1237 * reflected in the set, and vice-versa. The set supports element 1238 * removal, which removes the corresponding mapping from this map, 1239 * via the {@code Iterator.remove}, {@code Set.remove}, 1240 * {@code removeAll}, {@code retainAll}, and {@code clear} 1241 * operations. It does not support the {@code add} or 1242 * {@code addAll} operations. 1243 * 1244 * <p>The view's iterators and spliterators are 1245 * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 1246 * 1247 * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}, 1248 * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}. 1249 * 1250 * @return the set view 1251 */ 1252 public KeySetView<K,V> keySet() { 1253 KeySetView<K,V> ks; 1254 if ((ks = keySet) != null) return ks; 1255 return keySet = new KeySetView<K,V>(this, null); 1256 } 1257 1258 /** 1259 * Returns a {@link Collection} view of the values contained in this map. 1260 * The collection is backed by the map, so changes to the map are 1261 * reflected in the collection, and vice-versa. The collection 1262 * supports element removal, which removes the corresponding 1263 * mapping from this map, via the {@code Iterator.remove}, 1264 * {@code Collection.remove}, {@code removeAll}, 1265 * {@code retainAll}, and {@code clear} operations. It does not 1266 * support the {@code add} or {@code addAll} operations. 1267 * 1268 * <p>The view's iterators and spliterators are 1269 * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 1270 * 1271 * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT} 1272 * and {@link Spliterator#NONNULL}. 1273 * 1274 * @return the collection view 1275 */ 1276 public Collection<V> values() { 1277 ValuesView<K,V> vs; 1278 if ((vs = values) != null) return vs; 1279 return values = new ValuesView<K,V>(this); 1280 } 1281 1282 /** 1283 * Returns a {@link Set} view of the mappings contained in this map. 1284 * The set is backed by the map, so changes to the map are 1285 * reflected in the set, and vice-versa. The set supports element 1286 * removal, which removes the corresponding mapping from the map, 1287 * via the {@code Iterator.remove}, {@code Set.remove}, 1288 * {@code removeAll}, {@code retainAll}, and {@code clear} 1289 * operations. 1290 * 1291 * <p>The view's iterators and spliterators are 1292 * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 1293 * 1294 * <p>The view's {@code spliterator} reports {@link Spliterator#CONCURRENT}, 1295 * {@link Spliterator#DISTINCT}, and {@link Spliterator#NONNULL}. 1296 * 1297 * @return the set view 1298 */ 1299 public Set<Map.Entry<K,V>> entrySet() { 1300 EntrySetView<K,V> es; 1301 if ((es = entrySet) != null) return es; 1302 return entrySet = new EntrySetView<K,V>(this); 1303 } 1304 1305 /** 1306 * Returns the hash code value for this {@link Map}, i.e., 1307 * the sum of, for each key-value pair in the map, 1308 * {@code key.hashCode() ^ value.hashCode()}. 1309 * 1310 * @return the hash code value for this map 1311 */ 1312 public int hashCode() { 1313 int h = 0; 1314 Node<K,V>[] t; 1315 if ((t = table) != null) { 1316 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1317 for (Node<K,V> p; (p = it.advance()) != null; ) 1318 h += p.key.hashCode() ^ p.val.hashCode(); 1319 } 1320 return h; 1321 } 1322 1323 /** 1324 * Returns a string representation of this map. The string 1325 * representation consists of a list of key-value mappings (in no 1326 * particular order) enclosed in braces ("{@code {}}"). Adjacent 1327 * mappings are separated by the characters {@code ", "} (comma 1328 * and space). Each key-value mapping is rendered as the key 1329 * followed by an equals sign ("{@code =}") followed by the 1330 * associated value. 1331 * 1332 * @return a string representation of this map 1333 */ 1334 public String toString() { 1335 Node<K,V>[] t; 1336 int f = (t = table) == null ? 0 : t.length; 1337 Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); 1338 StringBuilder sb = new StringBuilder(); 1339 sb.append('{'); 1340 Node<K,V> p; 1341 if ((p = it.advance()) != null) { 1342 for (;;) { 1343 K k = p.key; 1344 V v = p.val; 1345 sb.append(k == this ? "(this Map)" : k); 1346 sb.append('='); 1347 sb.append(v == this ? "(this Map)" : v); 1348 if ((p = it.advance()) == null) 1349 break; 1350 sb.append(',').append(' '); 1351 } 1352 } 1353 return sb.append('}').toString(); 1354 } 1355 1356 /** 1357 * Compares the specified object with this map for equality. 1358 * Returns {@code true} if the given object is a map with the same 1359 * mappings as this map. This operation may return misleading 1360 * results if either map is concurrently modified during execution 1361 * of this method. 1362 * 1363 * @param o object to be compared for equality with this map 1364 * @return {@code true} if the specified object is equal to this map 1365 */ 1366 public boolean equals(Object o) { 1367 if (o != this) { 1368 if (!(o instanceof Map)) 1369 return false; 1370 Map<?,?> m = (Map<?,?>) o; 1371 Node<K,V>[] t; 1372 int f = (t = table) == null ? 0 : t.length; 1373 Traverser<K,V> it = new Traverser<K,V>(t, f, 0, f); 1374 for (Node<K,V> p; (p = it.advance()) != null; ) { 1375 V val = p.val; 1376 Object v = m.get(p.key); 1377 if (!Objects.equals(val, v)) 1378 return false; 1379 } 1380 for (Map.Entry<?,?> e : m.entrySet()) { 1381 Object mk, mv, v; 1382 if ((mk = e.getKey()) == null || 1383 (mv = e.getValue()) == null || 1384 (v = get(mk)) == null || 1385 !Objects.equals(mv, v)) 1386 return false; 1387 } 1388 } 1389 return true; 1390 } 1391 1392 /** 1393 * Stripped-down version of helper class used in previous version, 1394 * declared for the sake of serialization compatibility. 1395 */ 1396 static class Segment<K,V> extends ReentrantLock implements Serializable { 1397 private static final long serialVersionUID = 2249069246763182397L; 1398 final float loadFactor; 1399 Segment(float lf) { this.loadFactor = lf; } 1400 } 1401 1402 /** 1403 * Saves this map to a stream (that is, serializes it). 1404 * 1405 * @param s the stream 1406 * @throws java.io.IOException if an I/O error occurs 1407 * @serialData 1408 * the serialized fields, followed by the key (Object) and value 1409 * (Object) for each key-value mapping, followed by a null pair. 1410 * The key-value mappings are emitted in no particular order. 1411 */ 1412 private void writeObject(java.io.ObjectOutputStream s) 1413 throws java.io.IOException { 1414 // For serialization compatibility 1415 // Emulate segment calculation from previous version of this class 1416 int sshift = 0; 1417 int ssize = 1; 1418 while (ssize < DEFAULT_CONCURRENCY_LEVEL) { 1419 ++sshift; 1420 ssize <<= 1; 1421 } 1422 int segmentShift = 32 - sshift; 1423 int segmentMask = ssize - 1; 1424 @SuppressWarnings("unchecked") 1425 Segment<K,V>[] segments = (Segment<K,V>[]) 1426 new Segment<?,?>[DEFAULT_CONCURRENCY_LEVEL]; 1427 for (int i = 0; i < segments.length; ++i) 1428 segments[i] = new Segment<K,V>(LOAD_FACTOR); 1429 java.io.ObjectOutputStream.PutField streamFields = s.putFields(); 1430 streamFields.put("segments", segments); 1431 streamFields.put("segmentShift", segmentShift); 1432 streamFields.put("segmentMask", segmentMask); 1433 s.writeFields(); 1434 1435 Node<K,V>[] t; 1436 if ((t = table) != null) { 1437 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1438 for (Node<K,V> p; (p = it.advance()) != null; ) { 1439 s.writeObject(p.key); 1440 s.writeObject(p.val); 1441 } 1442 } 1443 s.writeObject(null); 1444 s.writeObject(null); 1445 } 1446 1447 /** 1448 * Reconstitutes this map from a stream (that is, deserializes it). 1449 * @param s the stream 1450 * @throws ClassNotFoundException if the class of a serialized object 1451 * could not be found 1452 * @throws java.io.IOException if an I/O error occurs 1453 */ 1454 private void readObject(java.io.ObjectInputStream s) 1455 throws java.io.IOException, ClassNotFoundException { 1456 /* 1457 * To improve performance in typical cases, we create nodes 1458 * while reading, then place in table once size is known. 1459 * However, we must also validate uniqueness and deal with 1460 * overpopulated bins while doing so, which requires 1461 * specialized versions of putVal mechanics. 1462 */ 1463 sizeCtl = -1; // force exclusion for table construction 1464 s.defaultReadObject(); 1465 long size = 0L; 1466 Node<K,V> p = null; 1467 for (;;) { 1468 @SuppressWarnings("unchecked") 1469 K k = (K) s.readObject(); 1470 @SuppressWarnings("unchecked") 1471 V v = (V) s.readObject(); 1472 if (k != null && v != null) { 1473 p = new Node<K,V>(spread(k.hashCode()), k, v, p); 1474 ++size; 1475 } 1476 else 1477 break; 1478 } 1479 if (size == 0L) 1480 sizeCtl = 0; 1481 else { 1482 long ts = (long)(1.0 + size / LOAD_FACTOR); 1483 int n = (ts >= (long)MAXIMUM_CAPACITY) ? 1484 MAXIMUM_CAPACITY : tableSizeFor((int)ts); 1485 @SuppressWarnings("unchecked") 1486 Node<K,V>[] tab = (Node<K,V>[])new Node<?,?>[n]; 1487 int mask = n - 1; 1488 long added = 0L; 1489 while (p != null) { 1490 boolean insertAtFront; 1491 Node<K,V> next = p.next, first; 1492 int h = p.hash, j = h & mask; 1493 if ((first = tabAt(tab, j)) == null) 1494 insertAtFront = true; 1495 else { 1496 K k = p.key; 1497 if (first.hash < 0) { 1498 TreeBin<K,V> t = (TreeBin<K,V>)first; 1499 if (t.putTreeVal(h, k, p.val) == null) 1500 ++added; 1501 insertAtFront = false; 1502 } 1503 else { 1504 int binCount = 0; 1505 insertAtFront = true; 1506 Node<K,V> q; K qk; 1507 for (q = first; q != null; q = q.next) { 1508 if (q.hash == h && 1509 ((qk = q.key) != null && Objects.equals(k, qk))) { 1510 insertAtFront = false; 1511 break; 1512 } 1513 ++binCount; 1514 } 1515 if (insertAtFront && binCount >= TREEIFY_THRESHOLD) { 1516 insertAtFront = false; 1517 ++added; 1518 p.next = first; 1519 TreeNode<K,V> hd = null, tl = null; 1520 for (q = p; q != null; q = q.next) { 1521 TreeNode<K,V> t = new TreeNode<K,V> 1522 (q.hash, q.key, q.val, null, null); 1523 if ((t.prev = tl) == null) 1524 hd = t; 1525 else 1526 tl.next = t; 1527 tl = t; 1528 } 1529 setTabAt(tab, j, new TreeBin<K,V>(hd)); 1530 } 1531 } 1532 } 1533 if (insertAtFront) { 1534 ++added; 1535 p.next = first; 1536 setTabAt(tab, j, p); 1537 } 1538 p = next; 1539 } 1540 table = tab; 1541 sizeCtl = n - (n >>> 2); 1542 baseCount = added; 1543 } 1544 } 1545 1546 // ConcurrentMap methods 1547 1548 /** 1549 * {@inheritDoc ConcurrentMap} 1550 * 1551 * @return the previous value associated with the specified key, 1552 * or {@code null} if there was no mapping for the key 1553 * @throws NullPointerException if the specified key or value is null 1554 */ 1555 public V putIfAbsent(K key, V value) { 1556 return putVal(key, value, true); 1557 } 1558 1559 /** 1560 * {@inheritDoc ConcurrentMap} 1561 * 1562 * @throws NullPointerException if the specified key is null 1563 * @return {@inheritDoc ConcurrentMap} 1564 */ 1565 public boolean remove(Object key, Object value) { 1566 if (key == null) 1567 throw new NullPointerException(); 1568 return value != null && replaceNode(key, null, value) != null; 1569 } 1570 1571 /** 1572 * {@inheritDoc ConcurrentMap} 1573 * 1574 * @throws NullPointerException if any of the arguments are null 1575 * @return {@inheritDoc ConcurrentMap} 1576 */ 1577 public boolean replace(K key, V oldValue, V newValue) { 1578 if (key == null || oldValue == null || newValue == null) 1579 throw new NullPointerException(); 1580 return replaceNode(key, newValue, oldValue) != null; 1581 } 1582 1583 /** 1584 * {@inheritDoc ConcurrentMap} 1585 * 1586 * @return the previous value associated with the specified key, 1587 * or {@code null} if there was no mapping for the key 1588 * @throws NullPointerException if the specified key or value is null 1589 */ 1590 public V replace(K key, V value) { 1591 if (key == null || value == null) 1592 throw new NullPointerException(); 1593 return replaceNode(key, value, null); 1594 } 1595 1596 // Overrides of JDK8+ Map extension method defaults 1597 1598 /** 1599 * Returns the value to which the specified key is mapped, or the 1600 * given default value if this map contains no mapping for the 1601 * key. 1602 * 1603 * @param key the key whose associated value is to be returned 1604 * @param defaultValue the value to return if this map contains 1605 * no mapping for the given key 1606 * @return the mapping for the key, if present; else the default value 1607 * @throws NullPointerException if the specified key is null 1608 */ 1609 public V getOrDefault(Object key, V defaultValue) { 1610 V v; 1611 return (v = get(key)) == null ? defaultValue : v; 1612 } 1613 1614 public void forEach(BiConsumer<? super K, ? super V> action) { 1615 if (action == null) throw new NullPointerException(); 1616 Node<K,V>[] t; 1617 if ((t = table) != null) { 1618 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1619 for (Node<K,V> p; (p = it.advance()) != null; ) { 1620 action.accept(p.key, p.val); 1621 } 1622 } 1623 } 1624 1625 public void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) { 1626 if (function == null) throw new NullPointerException(); 1627 Node<K,V>[] t; 1628 if ((t = table) != null) { 1629 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1630 for (Node<K,V> p; (p = it.advance()) != null; ) { 1631 V oldValue = p.val; 1632 for (K key = p.key;;) { 1633 V newValue = function.apply(key, oldValue); 1634 if (newValue == null) 1635 throw new NullPointerException(); 1636 if (replaceNode(key, newValue, oldValue) != null || 1637 (oldValue = get(key)) == null) 1638 break; 1639 } 1640 } 1641 } 1642 } 1643 1644 /** 1645 * Helper method for EntrySetView.removeIf. 1646 */ 1647 boolean removeEntryIf(Predicate<? super Entry<K,V>> function) { 1648 if (function == null) throw new NullPointerException(); 1649 Node<K,V>[] t; 1650 boolean removed = false; 1651 if ((t = table) != null) { 1652 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1653 for (Node<K,V> p; (p = it.advance()) != null; ) { 1654 K k = p.key; 1655 V v = p.val; 1656 Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v); 1657 if (function.test(e) && replaceNode(k, null, v) != null) 1658 removed = true; 1659 } 1660 } 1661 return removed; 1662 } 1663 1664 /** 1665 * Helper method for ValuesView.removeIf. 1666 */ 1667 boolean removeValueIf(Predicate<? super V> function) { 1668 if (function == null) throw new NullPointerException(); 1669 Node<K,V>[] t; 1670 boolean removed = false; 1671 if ((t = table) != null) { 1672 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 1673 for (Node<K,V> p; (p = it.advance()) != null; ) { 1674 K k = p.key; 1675 V v = p.val; 1676 if (function.test(v) && replaceNode(k, null, v) != null) 1677 removed = true; 1678 } 1679 } 1680 return removed; 1681 } 1682 1683 /** 1684 * If the specified key is not already associated with a value, 1685 * attempts to compute its value using the given mapping function 1686 * and enters it into this map unless {@code null}. The entire 1687 * method invocation is performed atomically. The supplied 1688 * function is invoked exactly once per invocation of this method 1689 * if the key is absent, else not at all. Some attempted update 1690 * operations on this map by other threads may be blocked while 1691 * computation is in progress, so the computation should be short 1692 * and simple. 1693 * 1694 * <p>The mapping function must not modify this map during computation. 1695 * 1696 * @param key key with which the specified value is to be associated 1697 * @param mappingFunction the function to compute a value 1698 * @return the current (existing or computed) value associated with 1699 * the specified key, or null if the computed value is null 1700 * @throws NullPointerException if the specified key or mappingFunction 1701 * is null 1702 * @throws IllegalStateException if the computation detectably 1703 * attempts a recursive update to this map that would 1704 * otherwise never complete 1705 * @throws RuntimeException or Error if the mappingFunction does so, 1706 * in which case the mapping is left unestablished 1707 */ 1708 public V computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction) { 1709 if (key == null || mappingFunction == null) 1710 throw new NullPointerException(); 1711 int h = spread(key.hashCode()); 1712 V val = null; 1713 int binCount = 0; 1714 for (Node<K,V>[] tab = table;;) { 1715 Node<K,V> f; int n, i, fh; K fk; V fv; 1716 if (tab == null || (n = tab.length) == 0) 1717 tab = initTable(); 1718 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 1719 Node<K,V> r = new ReservationNode<K,V>(); 1720 synchronized (r) { 1721 if (casTabAt(tab, i, null, r)) { 1722 binCount = 1; 1723 Node<K,V> node = null; 1724 try { 1725 if ((val = mappingFunction.apply(key)) != null) 1726 node = new Node<K,V>(h, key, val); 1727 } finally { 1728 setTabAt(tab, i, node); 1729 } 1730 } 1731 } 1732 if (binCount != 0) 1733 break; 1734 } 1735 else if ((fh = f.hash) == MOVED) 1736 tab = helpTransfer(tab, f); 1737 else if (fh == h // check first node without acquiring lock 1738 && ((fk = f.key) != null && Objects.equals(key, fk)) 1739 && (fv = f.val) != null) 1740 return fv; 1741 else { 1742 boolean added = false; 1743 synchronized (f) { 1744 if (tabAt(tab, i) == f) { 1745 if (fh >= 0) { 1746 binCount = 1; 1747 for (Node<K,V> e = f;; ++binCount) { 1748 K ek; 1749 if (e.hash == h && 1750 ((ek = e.key) == key || 1751 (ek != null && key.equals(ek)))) { 1752 val = e.val; 1753 break; 1754 } 1755 Node<K,V> pred = e; 1756 if ((e = e.next) == null) { 1757 if ((val = mappingFunction.apply(key)) != null) { 1758 if (pred.next != null) 1759 throw new IllegalStateException("Recursive update"); 1760 added = true; 1761 pred.next = new Node<K,V>(h, key, val); 1762 } 1763 break; 1764 } 1765 } 1766 } 1767 else if (f instanceof TreeBin) { 1768 binCount = 2; 1769 TreeBin<K,V> t = (TreeBin<K,V>)f; 1770 TreeNode<K,V> r, p; 1771 if ((r = t.root) != null && 1772 (p = r.findTreeNode(h, key, null)) != null) 1773 val = p.val; 1774 else if ((val = mappingFunction.apply(key)) != null) { 1775 added = true; 1776 t.putTreeVal(h, key, val); 1777 } 1778 } 1779 else if (f instanceof ReservationNode) 1780 throw new IllegalStateException("Recursive update"); 1781 } 1782 } 1783 if (binCount != 0) { 1784 if (binCount >= TREEIFY_THRESHOLD) 1785 treeifyBin(tab, i); 1786 if (!added) 1787 return val; 1788 break; 1789 } 1790 } 1791 } 1792 if (val != null) 1793 addCount(1L, binCount); 1794 return val; 1795 } 1796 1797 /** 1798 * If the value for the specified key is present, attempts to 1799 * compute a new mapping given the key and its current mapped 1800 * value. The entire method invocation is performed atomically. 1801 * The supplied function is invoked exactly once per invocation of 1802 * this method if the key is present, else not at all. Some 1803 * attempted update operations on this map by other threads may be 1804 * blocked while computation is in progress, so the computation 1805 * should be short and simple. 1806 * 1807 * <p>The remapping function must not modify this map during computation. 1808 * 1809 * @param key key with which a value may be associated 1810 * @param remappingFunction the function to compute a value 1811 * @return the new value associated with the specified key, or null if none 1812 * @throws NullPointerException if the specified key or remappingFunction 1813 * is null 1814 * @throws IllegalStateException if the computation detectably 1815 * attempts a recursive update to this map that would 1816 * otherwise never complete 1817 * @throws RuntimeException or Error if the remappingFunction does so, 1818 * in which case the mapping is unchanged 1819 */ 1820 public V computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1821 if (key == null || remappingFunction == null) 1822 throw new NullPointerException(); 1823 int h = spread(key.hashCode()); 1824 V val = null; 1825 int delta = 0; 1826 int binCount = 0; 1827 for (Node<K,V>[] tab = table;;) { 1828 Node<K,V> f; int n, i, fh; 1829 if (tab == null || (n = tab.length) == 0) 1830 tab = initTable(); 1831 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) 1832 break; 1833 else if ((fh = f.hash) == MOVED) 1834 tab = helpTransfer(tab, f); 1835 else { 1836 synchronized (f) { 1837 if (tabAt(tab, i) == f) { 1838 if (fh >= 0) { 1839 binCount = 1; 1840 for (Node<K,V> e = f, pred = null;; ++binCount) { 1841 K ek; 1842 if (e.hash == h && 1843 ((ek = e.key) != null && Objects.equals(key, ek))) { 1844 val = remappingFunction.apply(key, e.val); 1845 if (val != null) 1846 e.val = val; 1847 else { 1848 delta = -1; 1849 Node<K,V> en = e.next; 1850 if (pred != null) 1851 pred.next = en; 1852 else 1853 setTabAt(tab, i, en); 1854 } 1855 break; 1856 } 1857 pred = e; 1858 if ((e = e.next) == null) 1859 break; 1860 } 1861 } 1862 else if (f instanceof TreeBin) { 1863 binCount = 2; 1864 TreeBin<K,V> t = (TreeBin<K,V>)f; 1865 TreeNode<K,V> r, p; 1866 if ((r = t.root) != null && 1867 (p = r.findTreeNode(h, key, null)) != null) { 1868 val = remappingFunction.apply(key, p.val); 1869 if (val != null) 1870 p.val = val; 1871 else { 1872 delta = -1; 1873 if (t.removeTreeNode(p)) 1874 setTabAt(tab, i, untreeify(t.first)); 1875 } 1876 } 1877 } 1878 else if (f instanceof ReservationNode) 1879 throw new IllegalStateException("Recursive update"); 1880 } 1881 } 1882 if (binCount != 0) 1883 break; 1884 } 1885 } 1886 if (delta != 0) 1887 addCount((long)delta, binCount); 1888 return val; 1889 } 1890 1891 /** 1892 * Attempts to compute a mapping for the specified key and its 1893 * current mapped value (or {@code null} if there is no current 1894 * mapping). The entire method invocation is performed atomically. 1895 * The supplied function is invoked exactly once per invocation of 1896 * this method. Some attempted update operations on this map by 1897 * other threads may be blocked while computation is in progress, 1898 * so the computation should be short and simple. 1899 * 1900 * <p>The remapping function must not modify this map during computation. 1901 * 1902 * @param key key with which the specified value is to be associated 1903 * @param remappingFunction the function to compute a value 1904 * @return the new value associated with the specified key, or null if none 1905 * @throws NullPointerException if the specified key or remappingFunction 1906 * is null 1907 * @throws IllegalStateException if the computation detectably 1908 * attempts a recursive update to this map that would 1909 * otherwise never complete 1910 * @throws RuntimeException or Error if the remappingFunction does so, 1911 * in which case the mapping is unchanged 1912 */ 1913 public V compute(K key, 1914 BiFunction<? super K, ? super V, ? extends V> remappingFunction) { 1915 if (key == null || remappingFunction == null) 1916 throw new NullPointerException(); 1917 int h = spread(key.hashCode()); 1918 V val = null; 1919 int delta = 0; 1920 int binCount = 0; 1921 for (Node<K,V>[] tab = table;;) { 1922 Node<K,V> f; int n, i, fh; 1923 if (tab == null || (n = tab.length) == 0) 1924 tab = initTable(); 1925 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 1926 Node<K,V> r = new ReservationNode<K,V>(); 1927 synchronized (r) { 1928 if (casTabAt(tab, i, null, r)) { 1929 binCount = 1; 1930 Node<K,V> node = null; 1931 try { 1932 if ((val = remappingFunction.apply(key, null)) != null) { 1933 delta = 1; 1934 node = new Node<K,V>(h, key, val); 1935 } 1936 } finally { 1937 setTabAt(tab, i, node); 1938 } 1939 } 1940 } 1941 if (binCount != 0) 1942 break; 1943 } 1944 else if ((fh = f.hash) == MOVED) 1945 tab = helpTransfer(tab, f); 1946 else { 1947 synchronized (f) { 1948 if (tabAt(tab, i) == f) { 1949 if (fh >= 0) { 1950 binCount = 1; 1951 for (Node<K,V> e = f, pred = null;; ++binCount) { 1952 K ek; 1953 if (e.hash == h && 1954 ((ek = e.key) != null && Objects.equals(key, ek))) { 1955 val = remappingFunction.apply(key, e.val); 1956 if (val != null) 1957 e.val = val; 1958 else { 1959 delta = -1; 1960 Node<K,V> en = e.next; 1961 if (pred != null) 1962 pred.next = en; 1963 else 1964 setTabAt(tab, i, en); 1965 } 1966 break; 1967 } 1968 pred = e; 1969 if ((e = e.next) == null) { 1970 val = remappingFunction.apply(key, null); 1971 if (val != null) { 1972 if (pred.next != null) 1973 throw new IllegalStateException("Recursive update"); 1974 delta = 1; 1975 pred.next = new Node<K,V>(h, key, val); 1976 } 1977 break; 1978 } 1979 } 1980 } 1981 else if (f instanceof TreeBin) { 1982 binCount = 1; 1983 TreeBin<K,V> t = (TreeBin<K,V>)f; 1984 TreeNode<K,V> r, p; 1985 if ((r = t.root) != null) 1986 p = r.findTreeNode(h, key, null); 1987 else 1988 p = null; 1989 V pv = (p == null) ? null : p.val; 1990 val = remappingFunction.apply(key, pv); 1991 if (val != null) { 1992 if (p != null) 1993 p.val = val; 1994 else { 1995 delta = 1; 1996 t.putTreeVal(h, key, val); 1997 } 1998 } 1999 else if (p != null) { 2000 delta = -1; 2001 if (t.removeTreeNode(p)) 2002 setTabAt(tab, i, untreeify(t.first)); 2003 } 2004 } 2005 else if (f instanceof ReservationNode) 2006 throw new IllegalStateException("Recursive update"); 2007 } 2008 } 2009 if (binCount != 0) { 2010 if (binCount >= TREEIFY_THRESHOLD) 2011 treeifyBin(tab, i); 2012 break; 2013 } 2014 } 2015 } 2016 if (delta != 0) 2017 addCount((long)delta, binCount); 2018 return val; 2019 } 2020 2021 /** 2022 * If the specified key is not already associated with a 2023 * (non-null) value, associates it with the given value. 2024 * Otherwise, replaces the value with the results of the given 2025 * remapping function, or removes if {@code null}. The entire 2026 * method invocation is performed atomically. Some attempted 2027 * update operations on this map by other threads may be blocked 2028 * while computation is in progress, so the computation should be 2029 * short and simple, and must not attempt to update any other 2030 * mappings of this Map. 2031 * 2032 * @param key key with which the specified value is to be associated 2033 * @param value the value to use if absent 2034 * @param remappingFunction the function to recompute a value if present 2035 * @return the new value associated with the specified key, or null if none 2036 * @throws NullPointerException if the specified key or the 2037 * remappingFunction is null 2038 * @throws RuntimeException or Error if the remappingFunction does so, 2039 * in which case the mapping is unchanged 2040 */ 2041 public V merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction) { 2042 if (key == null || value == null || remappingFunction == null) 2043 throw new NullPointerException(); 2044 int h = spread(key.hashCode()); 2045 V val = null; 2046 int delta = 0; 2047 int binCount = 0; 2048 for (Node<K,V>[] tab = table;;) { 2049 Node<K,V> f; int n, i, fh; 2050 if (tab == null || (n = tab.length) == 0) 2051 tab = initTable(); 2052 else if ((f = tabAt(tab, i = (n - 1) & h)) == null) { 2053 if (casTabAt(tab, i, null, new Node<K,V>(h, key, value))) { 2054 delta = 1; 2055 val = value; 2056 break; 2057 } 2058 } 2059 else if ((fh = f.hash) == MOVED) 2060 tab = helpTransfer(tab, f); 2061 else { 2062 synchronized (f) { 2063 if (tabAt(tab, i) == f) { 2064 if (fh >= 0) { 2065 binCount = 1; 2066 for (Node<K,V> e = f, pred = null;; ++binCount) { 2067 K ek; 2068 if (e.hash == h && 2069 ((ek = e.key) != null && Objects.equals(key, ek))) { 2070 val = remappingFunction.apply(e.val, value); 2071 if (val != null) 2072 e.val = val; 2073 else { 2074 delta = -1; 2075 Node<K,V> en = e.next; 2076 if (pred != null) 2077 pred.next = en; 2078 else 2079 setTabAt(tab, i, en); 2080 } 2081 break; 2082 } 2083 pred = e; 2084 if ((e = e.next) == null) { 2085 delta = 1; 2086 val = value; 2087 pred.next = new Node<K,V>(h, key, val); 2088 break; 2089 } 2090 } 2091 } 2092 else if (f instanceof TreeBin) { 2093 binCount = 2; 2094 TreeBin<K,V> t = (TreeBin<K,V>)f; 2095 TreeNode<K,V> r = t.root; 2096 TreeNode<K,V> p = (r == null) ? null : 2097 r.findTreeNode(h, key, null); 2098 val = (p == null) ? value : 2099 remappingFunction.apply(p.val, value); 2100 if (val != null) { 2101 if (p != null) 2102 p.val = val; 2103 else { 2104 delta = 1; 2105 t.putTreeVal(h, key, val); 2106 } 2107 } 2108 else if (p != null) { 2109 delta = -1; 2110 if (t.removeTreeNode(p)) 2111 setTabAt(tab, i, untreeify(t.first)); 2112 } 2113 } 2114 else if (f instanceof ReservationNode) 2115 throw new IllegalStateException("Recursive update"); 2116 } 2117 } 2118 if (binCount != 0) { 2119 if (binCount >= TREEIFY_THRESHOLD) 2120 treeifyBin(tab, i); 2121 break; 2122 } 2123 } 2124 } 2125 if (delta != 0) 2126 addCount((long)delta, binCount); 2127 return val; 2128 } 2129 2130 // Hashtable legacy methods 2131 2132 /** 2133 * Tests if some key maps into the specified value in this table. 2134 * 2135 * <p>Note that this method is identical in functionality to 2136 * {@link #containsValue(Object)}, and exists solely to ensure 2137 * full compatibility with class {@link java.util.Hashtable}, 2138 * which supported this method prior to introduction of the 2139 * Java Collections Framework. 2140 * 2141 * @param value a value to search for 2142 * @return {@code true} if and only if some key maps to the 2143 * {@code value} argument in this table as 2144 * determined by the {@code equals} method; 2145 * {@code false} otherwise 2146 * @throws NullPointerException if the specified value is null 2147 */ 2148 public boolean contains(Object value) { 2149 return containsValue(value); 2150 } 2151 2152 /** 2153 * Returns an enumeration of the keys in this table. 2154 * 2155 * @return an enumeration of the keys in this table 2156 * @see #keySet() 2157 */ 2158 public Enumeration<K> keys() { 2159 Node<K,V>[] t; 2160 int f = (t = table) == null ? 0 : t.length; 2161 return new KeyIterator<K,V>(t, f, 0, f, this); 2162 } 2163 2164 /** 2165 * Returns an enumeration of the values in this table. 2166 * 2167 * @return an enumeration of the values in this table 2168 * @see #values() 2169 */ 2170 public Enumeration<V> elements() { 2171 Node<K,V>[] t; 2172 int f = (t = table) == null ? 0 : t.length; 2173 return new ValueIterator<K,V>(t, f, 0, f, this); 2174 } 2175 2176 // ConcurrentHashMap-only methods 2177 2178 /** 2179 * Returns the number of mappings. This method should be used 2180 * instead of {@link #size} because a ConcurrentHashMap may 2181 * contain more mappings than can be represented as an int. The 2182 * value returned is an estimate; the actual count may differ if 2183 * there are concurrent insertions or removals. 2184 * 2185 * @return the number of mappings 2186 * @since 1.8 2187 */ 2188 public long mappingCount() { 2189 long n = sumCount(); 2190 return (n < 0L) ? 0L : n; // ignore transient negative values 2191 } 2192 2193 /** 2194 * Creates a new {@link Set} backed by a ConcurrentHashMap 2195 * from the given type to {@code Boolean.TRUE}. 2196 * 2197 * @param <K> the element type of the returned set 2198 * @return the new set 2199 * @since 1.8 2200 */ 2201 public static <K> KeySetView<K,Boolean> newKeySet() { 2202 return new KeySetView<K,Boolean> 2203 (new ConcurrentHashMap<K,Boolean>(), Boolean.TRUE); 2204 } 2205 2206 /** 2207 * Creates a new {@link Set} backed by a ConcurrentHashMap 2208 * from the given type to {@code Boolean.TRUE}. 2209 * 2210 * @param initialCapacity The implementation performs internal 2211 * sizing to accommodate this many elements. 2212 * @param <K> the element type of the returned set 2213 * @return the new set 2214 * @throws IllegalArgumentException if the initial capacity of 2215 * elements is negative 2216 * @since 1.8 2217 */ 2218 public static <K> KeySetView<K,Boolean> newKeySet(int initialCapacity) { 2219 return new KeySetView<K,Boolean> 2220 (new ConcurrentHashMap<K,Boolean>(initialCapacity), Boolean.TRUE); 2221 } 2222 2223 /** 2224 * Returns a {@link Set} view of the keys in this map, using the 2225 * given common mapped value for any additions (i.e., {@link 2226 * Collection#add} and {@link Collection#addAll(Collection)}). 2227 * This is of course only appropriate if it is acceptable to use 2228 * the same value for all additions from this view. 2229 * 2230 * @param mappedValue the mapped value to use for any additions 2231 * @return the set view 2232 * @throws NullPointerException if the mappedValue is null 2233 */ 2234 public KeySetView<K,V> keySet(V mappedValue) { 2235 if (mappedValue == null) 2236 throw new NullPointerException(); 2237 return new KeySetView<K,V>(this, mappedValue); 2238 } 2239 2240 /* ---------------- Special Nodes -------------- */ 2241 2242 /** 2243 * A node inserted at head of bins during transfer operations. 2244 */ 2245 static final class ForwardingNode<K,V> extends Node<K,V> { 2246 final Node<K,V>[] nextTable; 2247 ForwardingNode(Node<K,V>[] tab) { 2248 super(MOVED, null, null); 2249 this.nextTable = tab; 2250 } 2251 2252 Node<K,V> find(int h, Object k) { 2253 // loop to avoid arbitrarily deep recursion on forwarding nodes 2254 outer: for (Node<K,V>[] tab = nextTable;;) { 2255 Node<K,V> e; int n; 2256 if (k == null || tab == null || (n = tab.length) == 0 || 2257 (e = tabAt(tab, (n - 1) & h)) == null) 2258 return null; 2259 for (;;) { 2260 int eh; K ek; 2261 if ((eh = e.hash) == h && 2262 ((ek = e.key) != null && Objects.equals(k, ek))) 2263 return e; 2264 if (eh < 0) { 2265 if (e instanceof ForwardingNode) { 2266 tab = ((ForwardingNode<K,V>)e).nextTable; 2267 continue outer; 2268 } 2269 else 2270 return e.find(h, k); 2271 } 2272 if ((e = e.next) == null) 2273 return null; 2274 } 2275 } 2276 } 2277 } 2278 2279 /** 2280 * A place-holder node used in computeIfAbsent and compute. 2281 */ 2282 static final class ReservationNode<K,V> extends Node<K,V> { 2283 ReservationNode() { 2284 super(RESERVED, null, null); 2285 } 2286 2287 Node<K,V> find(int h, Object k) { 2288 return null; 2289 } 2290 } 2291 2292 /* ---------------- Table Initialization and Resizing -------------- */ 2293 2294 /** 2295 * Returns the stamp bits for resizing a table of size n. 2296 * Must be negative when shifted left by RESIZE_STAMP_SHIFT. 2297 */ 2298 static final int resizeStamp(int n) { 2299 return Integer.numberOfLeadingZeros(n) | (1 << (RESIZE_STAMP_BITS - 1)); 2300 } 2301 2302 /** 2303 * Initializes table, using the size recorded in sizeCtl. 2304 */ 2305 private final Node<K,V>[] initTable() { 2306 Node<K,V>[] tab; int sc; 2307 while ((tab = table) == null || tab.length == 0) { 2308 if ((sc = sizeCtl) < 0) 2309 Thread.yield(); // lost initialization race; just spin 2310 else if (U.compareAndSetInt(this, SIZECTL, sc, -1)) { 2311 try { 2312 if ((tab = table) == null || tab.length == 0) { 2313 int n = (sc > 0) ? sc : DEFAULT_CAPACITY; 2314 @SuppressWarnings("unchecked") 2315 Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n]; 2316 table = tab = nt; 2317 sc = n - (n >>> 2); 2318 } 2319 } finally { 2320 sizeCtl = sc; 2321 } 2322 break; 2323 } 2324 } 2325 return tab; 2326 } 2327 2328 /** 2329 * Adds to count, and if table is too small and not already 2330 * resizing, initiates transfer. If already resizing, helps 2331 * perform transfer if work is available. Rechecks occupancy 2332 * after a transfer to see if another resize is already needed 2333 * because resizings are lagging additions. 2334 * 2335 * @param x the count to add 2336 * @param check if <0, don't check resize, if <= 1 only check if uncontended 2337 */ 2338 private final void addCount(long x, int check) { 2339 CounterCell[] cs; long b, s; 2340 if ((cs = counterCells) != null || 2341 !U.compareAndSetLong(this, BASECOUNT, b = baseCount, s = b + x)) { 2342 CounterCell c; long v; int m; 2343 boolean uncontended = true; 2344 if (cs == null || (m = cs.length - 1) < 0 || 2345 (c = cs[ThreadLocalRandom.getProbe() & m]) == null || 2346 !(uncontended = 2347 U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x))) { 2348 fullAddCount(x, uncontended); 2349 return; 2350 } 2351 if (check <= 1) 2352 return; 2353 s = sumCount(); 2354 } 2355 if (check >= 0) { 2356 Node<K,V>[] tab, nt; int n, sc; 2357 while (s >= (long)(sc = sizeCtl) && (tab = table) != null && 2358 (n = tab.length) < MAXIMUM_CAPACITY) { 2359 int rs = resizeStamp(n) << RESIZE_STAMP_SHIFT; 2360 if (sc < 0) { 2361 if (sc == rs + MAX_RESIZERS || sc == rs + 1 || 2362 (nt = nextTable) == null || transferIndex <= 0) 2363 break; 2364 if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1)) 2365 transfer(tab, nt); 2366 } 2367 else if (U.compareAndSetInt(this, SIZECTL, sc, rs + 2)) 2368 transfer(tab, null); 2369 s = sumCount(); 2370 } 2371 } 2372 } 2373 2374 /** 2375 * Helps transfer if a resize is in progress. 2376 */ 2377 final Node<K,V>[] helpTransfer(Node<K,V>[] tab, Node<K,V> f) { 2378 Node<K,V>[] nextTab; int sc; 2379 if (tab != null && (f instanceof ForwardingNode) && 2380 (nextTab = ((ForwardingNode<K,V>)f).nextTable) != null) { 2381 int rs = resizeStamp(tab.length) << RESIZE_STAMP_SHIFT; 2382 while (nextTab == nextTable && table == tab && 2383 (sc = sizeCtl) < 0) { 2384 if (sc == rs + MAX_RESIZERS || sc == rs + 1 || 2385 transferIndex <= 0) 2386 break; 2387 if (U.compareAndSetInt(this, SIZECTL, sc, sc + 1)) { 2388 transfer(tab, nextTab); 2389 break; 2390 } 2391 } 2392 return nextTab; 2393 } 2394 return table; 2395 } 2396 2397 /** 2398 * Tries to presize table to accommodate the given number of elements. 2399 * 2400 * @param size number of elements (doesn't need to be perfectly accurate) 2401 */ 2402 private final void tryPresize(int size) { 2403 int c = (size >= (MAXIMUM_CAPACITY >>> 1)) ? MAXIMUM_CAPACITY : 2404 tableSizeFor(size + (size >>> 1) + 1); 2405 int sc; 2406 while ((sc = sizeCtl) >= 0) { 2407 Node<K,V>[] tab = table; int n; 2408 if (tab == null || (n = tab.length) == 0) { 2409 n = (sc > c) ? sc : c; 2410 if (U.compareAndSetInt(this, SIZECTL, sc, -1)) { 2411 try { 2412 if (table == tab) { 2413 @SuppressWarnings("unchecked") 2414 Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n]; 2415 table = nt; 2416 sc = n - (n >>> 2); 2417 } 2418 } finally { 2419 sizeCtl = sc; 2420 } 2421 } 2422 } 2423 else if (c <= sc || n >= MAXIMUM_CAPACITY) 2424 break; 2425 else if (tab == table) { 2426 int rs = resizeStamp(n); 2427 if (U.compareAndSetInt(this, SIZECTL, sc, 2428 (rs << RESIZE_STAMP_SHIFT) + 2)) 2429 transfer(tab, null); 2430 } 2431 } 2432 } 2433 2434 /** 2435 * Moves and/or copies the nodes in each bin to new table. See 2436 * above for explanation. 2437 */ 2438 private final void transfer(Node<K,V>[] tab, Node<K,V>[] nextTab) { 2439 int n = tab.length, stride; 2440 if ((stride = (NCPU > 1) ? (n >>> 3) / NCPU : n) < MIN_TRANSFER_STRIDE) 2441 stride = MIN_TRANSFER_STRIDE; // subdivide range 2442 if (nextTab == null) { // initiating 2443 try { 2444 @SuppressWarnings("unchecked") 2445 Node<K,V>[] nt = (Node<K,V>[])new Node<?,?>[n << 1]; 2446 nextTab = nt; 2447 } catch (Throwable ex) { // try to cope with OOME 2448 sizeCtl = Integer.MAX_VALUE; 2449 return; 2450 } 2451 nextTable = nextTab; 2452 transferIndex = n; 2453 } 2454 int nextn = nextTab.length; 2455 ForwardingNode<K,V> fwd = new ForwardingNode<K,V>(nextTab); 2456 boolean advance = true; 2457 boolean finishing = false; // to ensure sweep before committing nextTab 2458 for (int i = 0, bound = 0;;) { 2459 Node<K,V> f; int fh; 2460 while (advance) { 2461 int nextIndex, nextBound; 2462 if (--i >= bound || finishing) 2463 advance = false; 2464 else if ((nextIndex = transferIndex) <= 0) { 2465 i = -1; 2466 advance = false; 2467 } 2468 else if (U.compareAndSetInt 2469 (this, TRANSFERINDEX, nextIndex, 2470 nextBound = (nextIndex > stride ? 2471 nextIndex - stride : 0))) { 2472 bound = nextBound; 2473 i = nextIndex - 1; 2474 advance = false; 2475 } 2476 } 2477 if (i < 0 || i >= n || i + n >= nextn) { 2478 int sc; 2479 if (finishing) { 2480 nextTable = null; 2481 table = nextTab; 2482 sizeCtl = (n << 1) - (n >>> 1); 2483 return; 2484 } 2485 if (U.compareAndSetInt(this, SIZECTL, sc = sizeCtl, sc - 1)) { 2486 if ((sc - 2) != resizeStamp(n) << RESIZE_STAMP_SHIFT) 2487 return; 2488 finishing = advance = true; 2489 i = n; // recheck before commit 2490 } 2491 } 2492 else if ((f = tabAt(tab, i)) == null) 2493 advance = casTabAt(tab, i, null, fwd); 2494 else if ((fh = f.hash) == MOVED) 2495 advance = true; // already processed 2496 else { 2497 synchronized (f) { 2498 if (tabAt(tab, i) == f) { 2499 Node<K,V> ln, hn; 2500 if (fh >= 0) { 2501 int runBit = fh & n; 2502 Node<K,V> lastRun = f; 2503 for (Node<K,V> p = f.next; p != null; p = p.next) { 2504 int b = p.hash & n; 2505 if (b != runBit) { 2506 runBit = b; 2507 lastRun = p; 2508 } 2509 } 2510 if (runBit == 0) { 2511 ln = lastRun; 2512 hn = null; 2513 } 2514 else { 2515 hn = lastRun; 2516 ln = null; 2517 } 2518 for (Node<K,V> p = f; p != lastRun; p = p.next) { 2519 int ph = p.hash; K pk = p.key; V pv = p.val; 2520 if ((ph & n) == 0) 2521 ln = new Node<K,V>(ph, pk, pv, ln); 2522 else 2523 hn = new Node<K,V>(ph, pk, pv, hn); 2524 } 2525 setTabAt(nextTab, i, ln); 2526 setTabAt(nextTab, i + n, hn); 2527 setTabAt(tab, i, fwd); 2528 advance = true; 2529 } 2530 else if (f instanceof TreeBin) { 2531 TreeBin<K,V> t = (TreeBin<K,V>)f; 2532 TreeNode<K,V> lo = null, loTail = null; 2533 TreeNode<K,V> hi = null, hiTail = null; 2534 int lc = 0, hc = 0; 2535 for (Node<K,V> e = t.first; e != null; e = e.next) { 2536 int h = e.hash; 2537 TreeNode<K,V> p = new TreeNode<K,V> 2538 (h, e.key, e.val, null, null); 2539 if ((h & n) == 0) { 2540 if ((p.prev = loTail) == null) 2541 lo = p; 2542 else 2543 loTail.next = p; 2544 loTail = p; 2545 ++lc; 2546 } 2547 else { 2548 if ((p.prev = hiTail) == null) 2549 hi = p; 2550 else 2551 hiTail.next = p; 2552 hiTail = p; 2553 ++hc; 2554 } 2555 } 2556 ln = (lc <= UNTREEIFY_THRESHOLD) ? untreeify(lo) : 2557 (hc != 0) ? new TreeBin<K,V>(lo) : t; 2558 hn = (hc <= UNTREEIFY_THRESHOLD) ? untreeify(hi) : 2559 (lc != 0) ? new TreeBin<K,V>(hi) : t; 2560 setTabAt(nextTab, i, ln); 2561 setTabAt(nextTab, i + n, hn); 2562 setTabAt(tab, i, fwd); 2563 advance = true; 2564 } 2565 else if (f instanceof ReservationNode) 2566 throw new IllegalStateException("Recursive update"); 2567 } 2568 } 2569 } 2570 } 2571 } 2572 2573 /* ---------------- Counter support -------------- */ 2574 2575 /** 2576 * A padded cell for distributing counts. Adapted from LongAdder 2577 * and Striped64. See their internal docs for explanation. 2578 */ 2579 @jdk.internal.vm.annotation.Contended static final class CounterCell { 2580 volatile long value; 2581 CounterCell(long x) { value = x; } 2582 } 2583 2584 final long sumCount() { 2585 CounterCell[] cs = counterCells; 2586 long sum = baseCount; 2587 if (cs != null) { 2588 for (CounterCell c : cs) 2589 if (c != null) 2590 sum += c.value; 2591 } 2592 return sum; 2593 } 2594 2595 // See LongAdder version for explanation 2596 private final void fullAddCount(long x, boolean wasUncontended) { 2597 int h; 2598 if ((h = ThreadLocalRandom.getProbe()) == 0) { 2599 ThreadLocalRandom.localInit(); // force initialization 2600 h = ThreadLocalRandom.getProbe(); 2601 wasUncontended = true; 2602 } 2603 boolean collide = false; // True if last slot nonempty 2604 for (;;) { 2605 CounterCell[] cs; CounterCell c; int n; long v; 2606 if ((cs = counterCells) != null && (n = cs.length) > 0) { 2607 if ((c = cs[(n - 1) & h]) == null) { 2608 if (cellsBusy == 0) { // Try to attach new Cell 2609 CounterCell r = new CounterCell(x); // Optimistic create 2610 if (cellsBusy == 0 && 2611 U.compareAndSetInt(this, CELLSBUSY, 0, 1)) { 2612 boolean created = false; 2613 try { // Recheck under lock 2614 CounterCell[] rs; int m, j; 2615 if ((rs = counterCells) != null && 2616 (m = rs.length) > 0 && 2617 rs[j = (m - 1) & h] == null) { 2618 rs[j] = r; 2619 created = true; 2620 } 2621 } finally { 2622 cellsBusy = 0; 2623 } 2624 if (created) 2625 break; 2626 continue; // Slot is now non-empty 2627 } 2628 } 2629 collide = false; 2630 } 2631 else if (!wasUncontended) // CAS already known to fail 2632 wasUncontended = true; // Continue after rehash 2633 else if (U.compareAndSetLong(c, CELLVALUE, v = c.value, v + x)) 2634 break; 2635 else if (counterCells != cs || n >= NCPU) 2636 collide = false; // At max size or stale 2637 else if (!collide) 2638 collide = true; 2639 else if (cellsBusy == 0 && 2640 U.compareAndSetInt(this, CELLSBUSY, 0, 1)) { 2641 try { 2642 if (counterCells == cs) // Expand table unless stale 2643 counterCells = Arrays.copyOf(cs, n << 1); 2644 } finally { 2645 cellsBusy = 0; 2646 } 2647 collide = false; 2648 continue; // Retry with expanded table 2649 } 2650 h = ThreadLocalRandom.advanceProbe(h); 2651 } 2652 else if (cellsBusy == 0 && counterCells == cs && 2653 U.compareAndSetInt(this, CELLSBUSY, 0, 1)) { 2654 boolean init = false; 2655 try { // Initialize table 2656 if (counterCells == cs) { 2657 CounterCell[] rs = new CounterCell[2]; 2658 rs[h & 1] = new CounterCell(x); 2659 counterCells = rs; 2660 init = true; 2661 } 2662 } finally { 2663 cellsBusy = 0; 2664 } 2665 if (init) 2666 break; 2667 } 2668 else if (U.compareAndSetLong(this, BASECOUNT, v = baseCount, v + x)) 2669 break; // Fall back on using base 2670 } 2671 } 2672 2673 /* ---------------- Conversion from/to TreeBins -------------- */ 2674 2675 /** 2676 * Replaces all linked nodes in bin at given index unless table is 2677 * too small, in which case resizes instead. 2678 */ 2679 private final void treeifyBin(Node<K,V>[] tab, int index) { 2680 Node<K,V> b; int n; 2681 if (tab != null) { 2682 if ((n = tab.length) < MIN_TREEIFY_CAPACITY) 2683 tryPresize(n << 1); 2684 else if ((b = tabAt(tab, index)) != null && b.hash >= 0) { 2685 synchronized (b) { 2686 if (tabAt(tab, index) == b) { 2687 TreeNode<K,V> hd = null, tl = null; 2688 for (Node<K,V> e = b; e != null; e = e.next) { 2689 TreeNode<K,V> p = 2690 new TreeNode<K,V>(e.hash, e.key, e.val, 2691 null, null); 2692 if ((p.prev = tl) == null) 2693 hd = p; 2694 else 2695 tl.next = p; 2696 tl = p; 2697 } 2698 setTabAt(tab, index, new TreeBin<K,V>(hd)); 2699 } 2700 } 2701 } 2702 } 2703 } 2704 2705 /** 2706 * Returns a list of non-TreeNodes replacing those in given list. 2707 */ 2708 static <K,V> Node<K,V> untreeify(Node<K,V> b) { 2709 Node<K,V> hd = null, tl = null; 2710 for (Node<K,V> q = b; q != null; q = q.next) { 2711 Node<K,V> p = new Node<K,V>(q.hash, q.key, q.val); 2712 if (tl == null) 2713 hd = p; 2714 else 2715 tl.next = p; 2716 tl = p; 2717 } 2718 return hd; 2719 } 2720 2721 /* ---------------- TreeNodes -------------- */ 2722 2723 /** 2724 * Nodes for use in TreeBins. 2725 */ 2726 static final class TreeNode<K,V> extends Node<K,V> { 2727 TreeNode<K,V> parent; // red-black tree links 2728 TreeNode<K,V> left; 2729 TreeNode<K,V> right; 2730 TreeNode<K,V> prev; // needed to unlink next upon deletion 2731 boolean red; 2732 2733 TreeNode(int hash, K key, V val, Node<K,V> next, 2734 TreeNode<K,V> parent) { 2735 super(hash, key, val, next); 2736 this.parent = parent; 2737 } 2738 2739 Node<K,V> find(int h, Object k) { 2740 return findTreeNode(h, k, null); 2741 } 2742 2743 /** 2744 * Returns the TreeNode (or null if not found) for the given key 2745 * starting at given root. 2746 */ 2747 final TreeNode<K,V> findTreeNode(int h, Object k, Class<?> kc) { 2748 if (k != null) { 2749 TreeNode<K,V> p = this; 2750 do { 2751 int ph, dir; K pk; TreeNode<K,V> q; 2752 TreeNode<K,V> pl = p.left, pr = p.right; 2753 if ((ph = p.hash) > h) 2754 p = pl; 2755 else if (ph < h) 2756 p = pr; 2757 else if ((pk = p.key) != null && Objects.equals(k, pk)) 2758 return p; 2759 else if (pl == null) 2760 p = pr; 2761 else if (pr == null) 2762 p = pl; 2763 else if ((kc != null || 2764 (kc = comparableClassFor(k)) != null) && 2765 (dir = compareComparables(kc, k, pk)) != 0) 2766 p = (dir < 0) ? pl : pr; 2767 else if ((q = pr.findTreeNode(h, k, kc)) != null) 2768 return q; 2769 else 2770 p = pl; 2771 } while (p != null); 2772 } 2773 return null; 2774 } 2775 } 2776 2777 /* ---------------- TreeBins -------------- */ 2778 2779 /** 2780 * TreeNodes used at the heads of bins. TreeBins do not hold user 2781 * keys or values, but instead point to list of TreeNodes and 2782 * their root. They also maintain a parasitic read-write lock 2783 * forcing writers (who hold bin lock) to wait for readers (who do 2784 * not) to complete before tree restructuring operations. 2785 */ 2786 static final class TreeBin<K,V> extends Node<K,V> { 2787 TreeNode<K,V> root; 2788 volatile TreeNode<K,V> first; 2789 volatile Thread waiter; 2790 volatile int lockState; 2791 // values for lockState 2792 static final int WRITER = 1; // set while holding write lock 2793 static final int WAITER = 2; // set when waiting for write lock 2794 static final int READER = 4; // increment value for setting read lock 2795 2796 /** 2797 * Tie-breaking utility for ordering insertions when equal 2798 * hashCodes and non-comparable. We don't require a total 2799 * order, just a consistent insertion rule to maintain 2800 * equivalence across rebalancings. Tie-breaking further than 2801 * necessary simplifies testing a bit. 2802 */ 2803 static int tieBreakOrder(Object a, Object b) { 2804 int d; 2805 if (a == null || b == null || 2806 (d = a.getClass().getName(). 2807 compareTo(b.getClass().getName())) == 0) 2808 d = (System.identityHashCode(a) <= System.identityHashCode(b) ? 2809 -1 : 1); 2810 return d; 2811 } 2812 2813 /** 2814 * Creates bin with initial set of nodes headed by b. 2815 */ 2816 TreeBin(TreeNode<K,V> b) { 2817 super(TREEBIN, null, null); 2818 this.first = b; 2819 TreeNode<K,V> r = null; 2820 for (TreeNode<K,V> x = b, next; x != null; x = next) { 2821 next = (TreeNode<K,V>)x.next; 2822 x.left = x.right = null; 2823 if (r == null) { 2824 x.parent = null; 2825 x.red = false; 2826 r = x; 2827 } 2828 else { 2829 K k = x.key; 2830 int h = x.hash; 2831 Class<?> kc = null; 2832 for (TreeNode<K,V> p = r;;) { 2833 int dir, ph; 2834 K pk = p.key; 2835 if ((ph = p.hash) > h) 2836 dir = -1; 2837 else if (ph < h) 2838 dir = 1; 2839 else if ((kc == null && 2840 (kc = comparableClassFor(k)) == null) || 2841 (dir = compareComparables(kc, k, pk)) == 0) 2842 dir = tieBreakOrder(k, pk); 2843 TreeNode<K,V> xp = p; 2844 if ((p = (dir <= 0) ? p.left : p.right) == null) { 2845 x.parent = xp; 2846 if (dir <= 0) 2847 xp.left = x; 2848 else 2849 xp.right = x; 2850 r = balanceInsertion(r, x); 2851 break; 2852 } 2853 } 2854 } 2855 } 2856 this.root = r; 2857 assert checkInvariants(root); 2858 } 2859 2860 /** 2861 * Acquires write lock for tree restructuring. 2862 */ 2863 private final void lockRoot() { 2864 if (!U.compareAndSetInt(this, LOCKSTATE, 0, WRITER)) 2865 contendedLock(); // offload to separate method 2866 } 2867 2868 /** 2869 * Releases write lock for tree restructuring. 2870 */ 2871 private final void unlockRoot() { 2872 lockState = 0; 2873 } 2874 2875 /** 2876 * Possibly blocks awaiting root lock. 2877 */ 2878 private final void contendedLock() { 2879 Thread current = Thread.currentThread(), w; 2880 for (int s;;) { 2881 if (((s = lockState) & ~WAITER) == 0) { 2882 if (U.compareAndSetInt(this, LOCKSTATE, s, WRITER)) { 2883 if (waiter == current) 2884 U.compareAndSetReference(this, WAITERTHREAD, current, null); 2885 return; 2886 } 2887 } 2888 else if ((s & WAITER) == 0) 2889 U.compareAndSetInt(this, LOCKSTATE, s, s | WAITER); 2890 else if ((w = waiter) == null) 2891 U.compareAndSetReference(this, WAITERTHREAD, null, current); 2892 else if (w == current) 2893 LockSupport.park(this); 2894 } 2895 } 2896 2897 /** 2898 * Returns matching node or null if none. Tries to search 2899 * using tree comparisons from root, but continues linear 2900 * search when lock not available. 2901 */ 2902 final Node<K,V> find(int h, Object k) { 2903 if (k != null) { 2904 for (Node<K,V> e = first; e != null; ) { 2905 int s; K ek; 2906 if (((s = lockState) & (WAITER|WRITER)) != 0) { 2907 if (e.hash == h && 2908 ((ek = e.key) != null && Objects.equals(k, ek))) 2909 return e; 2910 e = e.next; 2911 } 2912 else if (U.compareAndSetInt(this, LOCKSTATE, s, 2913 s + READER)) { 2914 TreeNode<K,V> r, p; 2915 try { 2916 p = ((r = root) == null ? null : 2917 r.findTreeNode(h, k, null)); 2918 } finally { 2919 Thread w; 2920 if (U.getAndAddInt(this, LOCKSTATE, -READER) == 2921 (READER|WAITER) && (w = waiter) != null) 2922 LockSupport.unpark(w); 2923 } 2924 return p; 2925 } 2926 } 2927 } 2928 return null; 2929 } 2930 2931 /** 2932 * Finds or adds a node. 2933 * @return null if added 2934 */ 2935 final TreeNode<K,V> putTreeVal(int h, K k, V v) { 2936 Class<?> kc = null; 2937 boolean searched = false; 2938 for (TreeNode<K,V> p = root;;) { 2939 int dir, ph; K pk; 2940 if (p == null) { 2941 first = root = new TreeNode<K,V>(h, k, v, null, null); 2942 break; 2943 } 2944 else if ((ph = p.hash) > h) 2945 dir = -1; 2946 else if (ph < h) 2947 dir = 1; 2948 else if ((pk = p.key) != null && Objects.equals(k, pk)) 2949 return p; 2950 else if ((kc == null && 2951 (kc = comparableClassFor(k)) == null) || 2952 (dir = compareComparables(kc, k, pk)) == 0) { 2953 if (!searched) { 2954 TreeNode<K,V> q, ch; 2955 searched = true; 2956 if (((ch = p.left) != null && 2957 (q = ch.findTreeNode(h, k, kc)) != null) || 2958 ((ch = p.right) != null && 2959 (q = ch.findTreeNode(h, k, kc)) != null)) 2960 return q; 2961 } 2962 dir = tieBreakOrder(k, pk); 2963 } 2964 2965 TreeNode<K,V> xp = p; 2966 if ((p = (dir <= 0) ? p.left : p.right) == null) { 2967 TreeNode<K,V> x, f = first; 2968 first = x = new TreeNode<K,V>(h, k, v, f, xp); 2969 if (f != null) 2970 f.prev = x; 2971 if (dir <= 0) 2972 xp.left = x; 2973 else 2974 xp.right = x; 2975 if (!xp.red) 2976 x.red = true; 2977 else { 2978 lockRoot(); 2979 try { 2980 root = balanceInsertion(root, x); 2981 } finally { 2982 unlockRoot(); 2983 } 2984 } 2985 break; 2986 } 2987 } 2988 assert checkInvariants(root); 2989 return null; 2990 } 2991 2992 /** 2993 * Removes the given node, that must be present before this 2994 * call. This is messier than typical red-black deletion code 2995 * because we cannot swap the contents of an interior node 2996 * with a leaf successor that is pinned by "next" pointers 2997 * that are accessible independently of lock. So instead we 2998 * swap the tree linkages. 2999 * 3000 * @return true if now too small, so should be untreeified 3001 */ 3002 final boolean removeTreeNode(TreeNode<K,V> p) { 3003 TreeNode<K,V> next = (TreeNode<K,V>)p.next; 3004 TreeNode<K,V> pred = p.prev; // unlink traversal pointers 3005 TreeNode<K,V> r, rl; 3006 if (pred == null) 3007 first = next; 3008 else 3009 pred.next = next; 3010 if (next != null) 3011 next.prev = pred; 3012 if (first == null) { 3013 root = null; 3014 return true; 3015 } 3016 if ((r = root) == null || r.right == null || // too small 3017 (rl = r.left) == null || rl.left == null) 3018 return true; 3019 lockRoot(); 3020 try { 3021 TreeNode<K,V> replacement; 3022 TreeNode<K,V> pl = p.left; 3023 TreeNode<K,V> pr = p.right; 3024 if (pl != null && pr != null) { 3025 TreeNode<K,V> s = pr, sl; 3026 while ((sl = s.left) != null) // find successor 3027 s = sl; 3028 boolean c = s.red; s.red = p.red; p.red = c; // swap colors 3029 TreeNode<K,V> sr = s.right; 3030 TreeNode<K,V> pp = p.parent; 3031 if (s == pr) { // p was s's direct parent 3032 p.parent = s; 3033 s.right = p; 3034 } 3035 else { 3036 TreeNode<K,V> sp = s.parent; 3037 if ((p.parent = sp) != null) { 3038 if (s == sp.left) 3039 sp.left = p; 3040 else 3041 sp.right = p; 3042 } 3043 if ((s.right = pr) != null) 3044 pr.parent = s; 3045 } 3046 p.left = null; 3047 if ((p.right = sr) != null) 3048 sr.parent = p; 3049 if ((s.left = pl) != null) 3050 pl.parent = s; 3051 if ((s.parent = pp) == null) 3052 r = s; 3053 else if (p == pp.left) 3054 pp.left = s; 3055 else 3056 pp.right = s; 3057 if (sr != null) 3058 replacement = sr; 3059 else 3060 replacement = p; 3061 } 3062 else if (pl != null) 3063 replacement = pl; 3064 else if (pr != null) 3065 replacement = pr; 3066 else 3067 replacement = p; 3068 if (replacement != p) { 3069 TreeNode<K,V> pp = replacement.parent = p.parent; 3070 if (pp == null) 3071 r = replacement; 3072 else if (p == pp.left) 3073 pp.left = replacement; 3074 else 3075 pp.right = replacement; 3076 p.left = p.right = p.parent = null; 3077 } 3078 3079 root = (p.red) ? r : balanceDeletion(r, replacement); 3080 3081 if (p == replacement) { // detach pointers 3082 TreeNode<K,V> pp; 3083 if ((pp = p.parent) != null) { 3084 if (p == pp.left) 3085 pp.left = null; 3086 else if (p == pp.right) 3087 pp.right = null; 3088 p.parent = null; 3089 } 3090 } 3091 } finally { 3092 unlockRoot(); 3093 } 3094 assert checkInvariants(root); 3095 return false; 3096 } 3097 3098 /* ------------------------------------------------------------ */ 3099 // Red-black tree methods, all adapted from CLR 3100 3101 static <K,V> TreeNode<K,V> rotateLeft(TreeNode<K,V> root, 3102 TreeNode<K,V> p) { 3103 TreeNode<K,V> r, pp, rl; 3104 if (p != null && (r = p.right) != null) { 3105 if ((rl = p.right = r.left) != null) 3106 rl.parent = p; 3107 if ((pp = r.parent = p.parent) == null) 3108 (root = r).red = false; 3109 else if (pp.left == p) 3110 pp.left = r; 3111 else 3112 pp.right = r; 3113 r.left = p; 3114 p.parent = r; 3115 } 3116 return root; 3117 } 3118 3119 static <K,V> TreeNode<K,V> rotateRight(TreeNode<K,V> root, 3120 TreeNode<K,V> p) { 3121 TreeNode<K,V> l, pp, lr; 3122 if (p != null && (l = p.left) != null) { 3123 if ((lr = p.left = l.right) != null) 3124 lr.parent = p; 3125 if ((pp = l.parent = p.parent) == null) 3126 (root = l).red = false; 3127 else if (pp.right == p) 3128 pp.right = l; 3129 else 3130 pp.left = l; 3131 l.right = p; 3132 p.parent = l; 3133 } 3134 return root; 3135 } 3136 3137 static <K,V> TreeNode<K,V> balanceInsertion(TreeNode<K,V> root, 3138 TreeNode<K,V> x) { 3139 x.red = true; 3140 for (TreeNode<K,V> xp, xpp, xppl, xppr;;) { 3141 if ((xp = x.parent) == null) { 3142 x.red = false; 3143 return x; 3144 } 3145 else if (!xp.red || (xpp = xp.parent) == null) 3146 return root; 3147 if (xp == (xppl = xpp.left)) { 3148 if ((xppr = xpp.right) != null && xppr.red) { 3149 xppr.red = false; 3150 xp.red = false; 3151 xpp.red = true; 3152 x = xpp; 3153 } 3154 else { 3155 if (x == xp.right) { 3156 root = rotateLeft(root, x = xp); 3157 xpp = (xp = x.parent) == null ? null : xp.parent; 3158 } 3159 if (xp != null) { 3160 xp.red = false; 3161 if (xpp != null) { 3162 xpp.red = true; 3163 root = rotateRight(root, xpp); 3164 } 3165 } 3166 } 3167 } 3168 else { 3169 if (xppl != null && xppl.red) { 3170 xppl.red = false; 3171 xp.red = false; 3172 xpp.red = true; 3173 x = xpp; 3174 } 3175 else { 3176 if (x == xp.left) { 3177 root = rotateRight(root, x = xp); 3178 xpp = (xp = x.parent) == null ? null : xp.parent; 3179 } 3180 if (xp != null) { 3181 xp.red = false; 3182 if (xpp != null) { 3183 xpp.red = true; 3184 root = rotateLeft(root, xpp); 3185 } 3186 } 3187 } 3188 } 3189 } 3190 } 3191 3192 static <K,V> TreeNode<K,V> balanceDeletion(TreeNode<K,V> root, 3193 TreeNode<K,V> x) { 3194 for (TreeNode<K,V> xp, xpl, xpr;;) { 3195 if (x == null || x == root) 3196 return root; 3197 else if ((xp = x.parent) == null) { 3198 x.red = false; 3199 return x; 3200 } 3201 else if (x.red) { 3202 x.red = false; 3203 return root; 3204 } 3205 else if ((xpl = xp.left) == x) { 3206 if ((xpr = xp.right) != null && xpr.red) { 3207 xpr.red = false; 3208 xp.red = true; 3209 root = rotateLeft(root, xp); 3210 xpr = (xp = x.parent) == null ? null : xp.right; 3211 } 3212 if (xpr == null) 3213 x = xp; 3214 else { 3215 TreeNode<K,V> sl = xpr.left, sr = xpr.right; 3216 if ((sr == null || !sr.red) && 3217 (sl == null || !sl.red)) { 3218 xpr.red = true; 3219 x = xp; 3220 } 3221 else { 3222 if (sr == null || !sr.red) { 3223 if (sl != null) 3224 sl.red = false; 3225 xpr.red = true; 3226 root = rotateRight(root, xpr); 3227 xpr = (xp = x.parent) == null ? 3228 null : xp.right; 3229 } 3230 if (xpr != null) { 3231 xpr.red = (xp == null) ? false : xp.red; 3232 if ((sr = xpr.right) != null) 3233 sr.red = false; 3234 } 3235 if (xp != null) { 3236 xp.red = false; 3237 root = rotateLeft(root, xp); 3238 } 3239 x = root; 3240 } 3241 } 3242 } 3243 else { // symmetric 3244 if (xpl != null && xpl.red) { 3245 xpl.red = false; 3246 xp.red = true; 3247 root = rotateRight(root, xp); 3248 xpl = (xp = x.parent) == null ? null : xp.left; 3249 } 3250 if (xpl == null) 3251 x = xp; 3252 else { 3253 TreeNode<K,V> sl = xpl.left, sr = xpl.right; 3254 if ((sl == null || !sl.red) && 3255 (sr == null || !sr.red)) { 3256 xpl.red = true; 3257 x = xp; 3258 } 3259 else { 3260 if (sl == null || !sl.red) { 3261 if (sr != null) 3262 sr.red = false; 3263 xpl.red = true; 3264 root = rotateLeft(root, xpl); 3265 xpl = (xp = x.parent) == null ? 3266 null : xp.left; 3267 } 3268 if (xpl != null) { 3269 xpl.red = (xp == null) ? false : xp.red; 3270 if ((sl = xpl.left) != null) 3271 sl.red = false; 3272 } 3273 if (xp != null) { 3274 xp.red = false; 3275 root = rotateRight(root, xp); 3276 } 3277 x = root; 3278 } 3279 } 3280 } 3281 } 3282 } 3283 3284 /** 3285 * Checks invariants recursively for the tree of Nodes rooted at t. 3286 */ 3287 static <K,V> boolean checkInvariants(TreeNode<K,V> t) { 3288 TreeNode<K,V> tp = t.parent, tl = t.left, tr = t.right, 3289 tb = t.prev, tn = (TreeNode<K,V>)t.next; 3290 if (tb != null && tb.next != t) 3291 return false; 3292 if (tn != null && tn.prev != t) 3293 return false; 3294 if (tp != null && t != tp.left && t != tp.right) 3295 return false; 3296 if (tl != null && (tl.parent != t || tl.hash > t.hash)) 3297 return false; 3298 if (tr != null && (tr.parent != t || tr.hash < t.hash)) 3299 return false; 3300 if (t.red && tl != null && tl.red && tr != null && tr.red) 3301 return false; 3302 if (tl != null && !checkInvariants(tl)) 3303 return false; 3304 if (tr != null && !checkInvariants(tr)) 3305 return false; 3306 return true; 3307 } 3308 3309 private static final long LOCKSTATE 3310 = U.objectFieldOffset(TreeBin.class, "lockState"); 3311 private static final long WAITERTHREAD 3312 = U.objectFieldOffset(TreeBin.class, "waiter"); 3313 } 3314 3315 /* ----------------Table Traversal -------------- */ 3316 3317 /** 3318 * Records the table, its length, and current traversal index for a 3319 * traverser that must process a region of a forwarded table before 3320 * proceeding with current table. 3321 */ 3322 static final class TableStack<K,V> { 3323 int length; 3324 int index; 3325 Node<K,V>[] tab; 3326 TableStack<K,V> next; 3327 } 3328 3329 /** 3330 * Encapsulates traversal for methods such as containsValue; also 3331 * serves as a base class for other iterators and spliterators. 3332 * 3333 * Method advance visits once each still-valid node that was 3334 * reachable upon iterator construction. It might miss some that 3335 * were added to a bin after the bin was visited, which is OK wrt 3336 * consistency guarantees. Maintaining this property in the face 3337 * of possible ongoing resizes requires a fair amount of 3338 * bookkeeping state that is difficult to optimize away amidst 3339 * volatile accesses. Even so, traversal maintains reasonable 3340 * throughput. 3341 * 3342 * Normally, iteration proceeds bin-by-bin traversing lists. 3343 * However, if the table has been resized, then all future steps 3344 * must traverse both the bin at the current index as well as at 3345 * (index + baseSize); and so on for further resizings. To 3346 * paranoically cope with potential sharing by users of iterators 3347 * across threads, iteration terminates if a bounds checks fails 3348 * for a table read. 3349 */ 3350 static class Traverser<K,V> { 3351 Node<K,V>[] tab; // current table; updated if resized 3352 Node<K,V> next; // the next entry to use 3353 TableStack<K,V> stack, spare; // to save/restore on ForwardingNodes 3354 int index; // index of bin to use next 3355 int baseIndex; // current index of initial table 3356 int baseLimit; // index bound for initial table 3357 final int baseSize; // initial table size 3358 3359 Traverser(Node<K,V>[] tab, int size, int index, int limit) { 3360 this.tab = tab; 3361 this.baseSize = size; 3362 this.baseIndex = this.index = index; 3363 this.baseLimit = limit; 3364 this.next = null; 3365 } 3366 3367 /** 3368 * Advances if possible, returning next valid node, or null if none. 3369 */ 3370 final Node<K,V> advance() { 3371 Node<K,V> e; 3372 if ((e = next) != null) 3373 e = e.next; 3374 for (;;) { 3375 Node<K,V>[] t; int i, n; // must use locals in checks 3376 if (e != null) 3377 return next = e; 3378 if (baseIndex >= baseLimit || (t = tab) == null || 3379 (n = t.length) <= (i = index) || i < 0) 3380 return next = null; 3381 if ((e = tabAt(t, i)) != null && e.hash < 0) { 3382 if (e instanceof ForwardingNode) { 3383 tab = ((ForwardingNode<K,V>)e).nextTable; 3384 e = null; 3385 pushState(t, i, n); 3386 continue; 3387 } 3388 else if (e instanceof TreeBin) 3389 e = ((TreeBin<K,V>)e).first; 3390 else 3391 e = null; 3392 } 3393 if (stack != null) 3394 recoverState(n); 3395 else if ((index = i + baseSize) >= n) 3396 index = ++baseIndex; // visit upper slots if present 3397 } 3398 } 3399 3400 /** 3401 * Saves traversal state upon encountering a forwarding node. 3402 */ 3403 private void pushState(Node<K,V>[] t, int i, int n) { 3404 TableStack<K,V> s = spare; // reuse if possible 3405 if (s != null) 3406 spare = s.next; 3407 else 3408 s = new TableStack<K,V>(); 3409 s.tab = t; 3410 s.length = n; 3411 s.index = i; 3412 s.next = stack; 3413 stack = s; 3414 } 3415 3416 /** 3417 * Possibly pops traversal state. 3418 * 3419 * @param n length of current table 3420 */ 3421 private void recoverState(int n) { 3422 TableStack<K,V> s; int len; 3423 while ((s = stack) != null && (index += (len = s.length)) >= n) { 3424 n = len; 3425 index = s.index; 3426 tab = s.tab; 3427 s.tab = null; 3428 TableStack<K,V> next = s.next; 3429 s.next = spare; // save for reuse 3430 stack = next; 3431 spare = s; 3432 } 3433 if (s == null && (index += baseSize) >= n) 3434 index = ++baseIndex; 3435 } 3436 } 3437 3438 /** 3439 * Base of key, value, and entry Iterators. Adds fields to 3440 * Traverser to support iterator.remove. 3441 */ 3442 static class BaseIterator<K,V> extends Traverser<K,V> { 3443 final ConcurrentHashMap<K,V> map; 3444 Node<K,V> lastReturned; 3445 BaseIterator(Node<K,V>[] tab, int size, int index, int limit, 3446 ConcurrentHashMap<K,V> map) { 3447 super(tab, size, index, limit); 3448 this.map = map; 3449 advance(); 3450 } 3451 3452 public final boolean hasNext() { return next != null; } 3453 public final boolean hasMoreElements() { return next != null; } 3454 3455 public final void remove() { 3456 Node<K,V> p; 3457 if ((p = lastReturned) == null) 3458 throw new IllegalStateException(); 3459 lastReturned = null; 3460 map.replaceNode(p.key, null, null); 3461 } 3462 } 3463 3464 static final class KeyIterator<K,V> extends BaseIterator<K,V> 3465 implements Iterator<K>, Enumeration<K> { 3466 KeyIterator(Node<K,V>[] tab, int size, int index, int limit, 3467 ConcurrentHashMap<K,V> map) { 3468 super(tab, size, index, limit, map); 3469 } 3470 3471 public final K next() { 3472 Node<K,V> p; 3473 if ((p = next) == null) 3474 throw new NoSuchElementException(); 3475 K k = p.key; 3476 lastReturned = p; 3477 advance(); 3478 return k; 3479 } 3480 3481 public final K nextElement() { return next(); } 3482 } 3483 3484 static final class ValueIterator<K,V> extends BaseIterator<K,V> 3485 implements Iterator<V>, Enumeration<V> { 3486 ValueIterator(Node<K,V>[] tab, int size, int index, int limit, 3487 ConcurrentHashMap<K,V> map) { 3488 super(tab, size, index, limit, map); 3489 } 3490 3491 public final V next() { 3492 Node<K,V> p; 3493 if ((p = next) == null) 3494 throw new NoSuchElementException(); 3495 V v = p.val; 3496 lastReturned = p; 3497 advance(); 3498 return v; 3499 } 3500 3501 public final V nextElement() { return next(); } 3502 } 3503 3504 static final class EntryIterator<K,V> extends BaseIterator<K,V> 3505 implements Iterator<Map.Entry<K,V>> { 3506 EntryIterator(Node<K,V>[] tab, int size, int index, int limit, 3507 ConcurrentHashMap<K,V> map) { 3508 super(tab, size, index, limit, map); 3509 } 3510 3511 public final Map.Entry<K,V> next() { 3512 Node<K,V> p; 3513 if ((p = next) == null) 3514 throw new NoSuchElementException(); 3515 K k = p.key; 3516 V v = p.val; 3517 lastReturned = p; 3518 advance(); 3519 return new MapEntry<K,V>(k, v, map); 3520 } 3521 } 3522 3523 /** 3524 * Exported Entry for EntryIterator. 3525 */ 3526 static final class MapEntry<K,V> implements Map.Entry<K,V> { 3527 final K key; // non-null 3528 V val; // non-null 3529 final ConcurrentHashMap<K,V> map; 3530 MapEntry(K key, V val, ConcurrentHashMap<K,V> map) { 3531 this.key = key; 3532 this.val = val; 3533 this.map = map; 3534 } 3535 public K getKey() { return key; } 3536 public V getValue() { return val; } 3537 public int hashCode() { return key.hashCode() ^ val.hashCode(); } 3538 public String toString() { 3539 return Helpers.mapEntryToString(key, val); 3540 } 3541 3542 public boolean equals(Object o) { 3543 Object k, v; Map.Entry<?,?> e; 3544 return ((o instanceof Map.Entry) && 3545 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 3546 (v = e.getValue()) != null && 3547 Objects.equals(k, key) && 3548 Objects.equals(v, val)); 3549 } 3550 3551 /** 3552 * Sets our entry's value and writes through to the map. The 3553 * value to return is somewhat arbitrary here. Since we do not 3554 * necessarily track asynchronous changes, the most recent 3555 * "previous" value could be different from what we return (or 3556 * could even have been removed, in which case the put will 3557 * re-establish). We do not and cannot guarantee more. 3558 */ 3559 public V setValue(V value) { 3560 if (value == null) throw new NullPointerException(); 3561 V v = val; 3562 val = value; 3563 map.put(key, value); 3564 return v; 3565 } 3566 } 3567 3568 static final class KeySpliterator<K,V> extends Traverser<K,V> 3569 implements Spliterator<K> { 3570 long est; // size estimate 3571 KeySpliterator(Node<K,V>[] tab, int size, int index, int limit, 3572 long est) { 3573 super(tab, size, index, limit); 3574 this.est = est; 3575 } 3576 3577 public KeySpliterator<K,V> trySplit() { 3578 int i, f, h; 3579 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3580 new KeySpliterator<K,V>(tab, baseSize, baseLimit = h, 3581 f, est >>>= 1); 3582 } 3583 3584 public void forEachRemaining(Consumer<? super K> action) { 3585 if (action == null) throw new NullPointerException(); 3586 for (Node<K,V> p; (p = advance()) != null;) 3587 action.accept(p.key); 3588 } 3589 3590 public boolean tryAdvance(Consumer<? super K> action) { 3591 if (action == null) throw new NullPointerException(); 3592 Node<K,V> p; 3593 if ((p = advance()) == null) 3594 return false; 3595 action.accept(p.key); 3596 return true; 3597 } 3598 3599 public long estimateSize() { return est; } 3600 3601 public int characteristics() { 3602 return Spliterator.DISTINCT | Spliterator.CONCURRENT | 3603 Spliterator.NONNULL; 3604 } 3605 } 3606 3607 static final class ValueSpliterator<K,V> extends Traverser<K,V> 3608 implements Spliterator<V> { 3609 long est; // size estimate 3610 ValueSpliterator(Node<K,V>[] tab, int size, int index, int limit, 3611 long est) { 3612 super(tab, size, index, limit); 3613 this.est = est; 3614 } 3615 3616 public ValueSpliterator<K,V> trySplit() { 3617 int i, f, h; 3618 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3619 new ValueSpliterator<K,V>(tab, baseSize, baseLimit = h, 3620 f, est >>>= 1); 3621 } 3622 3623 public void forEachRemaining(Consumer<? super V> action) { 3624 if (action == null) throw new NullPointerException(); 3625 for (Node<K,V> p; (p = advance()) != null;) 3626 action.accept(p.val); 3627 } 3628 3629 public boolean tryAdvance(Consumer<? super V> action) { 3630 if (action == null) throw new NullPointerException(); 3631 Node<K,V> p; 3632 if ((p = advance()) == null) 3633 return false; 3634 action.accept(p.val); 3635 return true; 3636 } 3637 3638 public long estimateSize() { return est; } 3639 3640 public int characteristics() { 3641 return Spliterator.CONCURRENT | Spliterator.NONNULL; 3642 } 3643 } 3644 3645 static final class EntrySpliterator<K,V> extends Traverser<K,V> 3646 implements Spliterator<Map.Entry<K,V>> { 3647 final ConcurrentHashMap<K,V> map; // To export MapEntry 3648 long est; // size estimate 3649 EntrySpliterator(Node<K,V>[] tab, int size, int index, int limit, 3650 long est, ConcurrentHashMap<K,V> map) { 3651 super(tab, size, index, limit); 3652 this.map = map; 3653 this.est = est; 3654 } 3655 3656 public EntrySpliterator<K,V> trySplit() { 3657 int i, f, h; 3658 return (h = ((i = baseIndex) + (f = baseLimit)) >>> 1) <= i ? null : 3659 new EntrySpliterator<K,V>(tab, baseSize, baseLimit = h, 3660 f, est >>>= 1, map); 3661 } 3662 3663 public void forEachRemaining(Consumer<? super Map.Entry<K,V>> action) { 3664 if (action == null) throw new NullPointerException(); 3665 for (Node<K,V> p; (p = advance()) != null; ) 3666 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 3667 } 3668 3669 public boolean tryAdvance(Consumer<? super Map.Entry<K,V>> action) { 3670 if (action == null) throw new NullPointerException(); 3671 Node<K,V> p; 3672 if ((p = advance()) == null) 3673 return false; 3674 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 3675 return true; 3676 } 3677 3678 public long estimateSize() { return est; } 3679 3680 public int characteristics() { 3681 return Spliterator.DISTINCT | Spliterator.CONCURRENT | 3682 Spliterator.NONNULL; 3683 } 3684 } 3685 3686 // Parallel bulk operations 3687 3688 /** 3689 * Computes initial batch value for bulk tasks. The returned value 3690 * is approximately exp2 of the number of times (minus one) to 3691 * split task by two before executing leaf action. This value is 3692 * faster to compute and more convenient to use as a guide to 3693 * splitting than is the depth, since it is used while dividing by 3694 * two anyway. 3695 */ 3696 final int batchFor(long b) { 3697 long n; 3698 if (b == Long.MAX_VALUE || (n = sumCount()) <= 1L || n < b) 3699 return 0; 3700 int sp = ForkJoinPool.getCommonPoolParallelism() << 2; // slack of 4 3701 return (b <= 0L || (n /= b) >= sp) ? sp : (int)n; 3702 } 3703 3704 /** 3705 * Performs the given {@linkplain ##Bulk bulk} action for each (key, value). 3706 * 3707 * @param parallelismThreshold the (estimated) number of elements 3708 * needed for this operation to be executed in parallel 3709 * @param action the action 3710 * @since 1.8 3711 */ 3712 public void forEach(long parallelismThreshold, 3713 BiConsumer<? super K,? super V> action) { 3714 if (action == null) throw new NullPointerException(); 3715 new ForEachMappingTask<K,V> 3716 (null, batchFor(parallelismThreshold), 0, 0, table, 3717 action).invoke(); 3718 } 3719 3720 /** 3721 * Performs the given {@linkplain ##Bulk bulk} action for each non-null transformation 3722 * of each (key, value). 3723 * 3724 * @param parallelismThreshold the (estimated) number of elements 3725 * needed for this operation to be executed in parallel 3726 * @param transformer a function returning the transformation 3727 * for an element, or null if there is no transformation (in 3728 * which case the action is not applied) 3729 * @param action the action 3730 * @param <U> the return type of the transformer 3731 * @since 1.8 3732 */ 3733 public <U> void forEach(long parallelismThreshold, 3734 BiFunction<? super K, ? super V, ? extends U> transformer, 3735 Consumer<? super U> action) { 3736 if (transformer == null || action == null) 3737 throw new NullPointerException(); 3738 new ForEachTransformedMappingTask<K,V,U> 3739 (null, batchFor(parallelismThreshold), 0, 0, table, 3740 transformer, action).invoke(); 3741 } 3742 3743 /** 3744 * Returns a non-null result from applying the given {@linkplain ##Bulk bulk} search 3745 * function on each (key, value), or null if none. Upon 3746 * success, further element processing is suppressed and the 3747 * results of any other parallel invocations of the search 3748 * function are ignored. 3749 * 3750 * @param parallelismThreshold the (estimated) number of elements 3751 * needed for this operation to be executed in parallel 3752 * @param searchFunction a function returning a non-null 3753 * result on success, else null 3754 * @param <U> the return type of the search function 3755 * @return a non-null result from applying the given search 3756 * function on each (key, value), or null if none 3757 * @since 1.8 3758 */ 3759 public <U> U search(long parallelismThreshold, 3760 BiFunction<? super K, ? super V, ? extends U> searchFunction) { 3761 if (searchFunction == null) throw new NullPointerException(); 3762 return new SearchMappingsTask<K,V,U> 3763 (null, batchFor(parallelismThreshold), 0, 0, table, 3764 searchFunction, new AtomicReference<U>()).invoke(); 3765 } 3766 3767 /** 3768 * Returns the result of accumulating the given {@linkplain ##Bulk bulk} transformation 3769 * of all (key, value) pairs using the given reducer to 3770 * combine values, or null if none. 3771 * 3772 * @param parallelismThreshold the (estimated) number of elements 3773 * needed for this operation to be executed in parallel 3774 * @param transformer a function returning the transformation 3775 * for an element, or null if there is no transformation (in 3776 * which case it is not combined) 3777 * @param reducer a commutative associative combining function 3778 * @param <U> the return type of the transformer 3779 * @return the result of accumulating the given transformation 3780 * of all (key, value) pairs 3781 * @since 1.8 3782 */ 3783 public <U> U reduce(long parallelismThreshold, 3784 BiFunction<? super K, ? super V, ? extends U> transformer, 3785 BiFunction<? super U, ? super U, ? extends U> reducer) { 3786 if (transformer == null || reducer == null) 3787 throw new NullPointerException(); 3788 return new MapReduceMappingsTask<K,V,U> 3789 (null, batchFor(parallelismThreshold), 0, 0, table, 3790 null, transformer, reducer).invoke(); 3791 } 3792 3793 /** 3794 * Returns the result of accumulating the given {@linkplain ##Bulk bulk} transformation 3795 * of all (key, value) pairs using the given reducer to 3796 * combine values, and the given basis as an identity value. 3797 * 3798 * @param parallelismThreshold the (estimated) number of elements 3799 * needed for this operation to be executed in parallel 3800 * @param transformer a function returning the transformation 3801 * for an element 3802 * @param basis the identity (initial default value) for the reduction 3803 * @param reducer a commutative associative combining function 3804 * @return the result of accumulating the given transformation 3805 * of all (key, value) pairs 3806 * @since 1.8 3807 */ 3808 public double reduceToDouble(long parallelismThreshold, 3809 ToDoubleBiFunction<? super K, ? super V> transformer, 3810 double basis, 3811 DoubleBinaryOperator reducer) { 3812 if (transformer == null || reducer == null) 3813 throw new NullPointerException(); 3814 return new MapReduceMappingsToDoubleTask<K,V> 3815 (null, batchFor(parallelismThreshold), 0, 0, table, 3816 null, transformer, basis, reducer).invoke(); 3817 } 3818 3819 /** 3820 * Returns the result of accumulating the given {@linkplain ##Bulk bulk} transformation 3821 * of all (key, value) pairs using the given reducer to 3822 * combine values, and the given basis as an identity value. 3823 * 3824 * @param parallelismThreshold the (estimated) number of elements 3825 * needed for this operation to be executed in parallel 3826 * @param transformer a function returning the transformation 3827 * for an element 3828 * @param basis the identity (initial default value) for the reduction 3829 * @param reducer a commutative associative combining function 3830 * @return the result of accumulating the given transformation 3831 * of all (key, value) pairs 3832 * @since 1.8 3833 */ 3834 public long reduceToLong(long parallelismThreshold, 3835 ToLongBiFunction<? super K, ? super V> transformer, 3836 long basis, 3837 LongBinaryOperator reducer) { 3838 if (transformer == null || reducer == null) 3839 throw new NullPointerException(); 3840 return new MapReduceMappingsToLongTask<K,V> 3841 (null, batchFor(parallelismThreshold), 0, 0, table, 3842 null, transformer, basis, reducer).invoke(); 3843 } 3844 3845 /** 3846 * Returns the result of accumulating the given {@linkplain ##Bulk bulk} transformation 3847 * of all (key, value) pairs using the given reducer to 3848 * combine values, and the given basis as an identity value. 3849 * 3850 * @param parallelismThreshold the (estimated) number of elements 3851 * needed for this operation to be executed in parallel 3852 * @param transformer a function returning the transformation 3853 * for an element 3854 * @param basis the identity (initial default value) for the reduction 3855 * @param reducer a commutative associative combining function 3856 * @return the result of accumulating the given transformation 3857 * of all (key, value) pairs 3858 * @since 1.8 3859 */ 3860 public int reduceToInt(long parallelismThreshold, 3861 ToIntBiFunction<? super K, ? super V> transformer, 3862 int basis, 3863 IntBinaryOperator reducer) { 3864 if (transformer == null || reducer == null) 3865 throw new NullPointerException(); 3866 return new MapReduceMappingsToIntTask<K,V> 3867 (null, batchFor(parallelismThreshold), 0, 0, table, 3868 null, transformer, basis, reducer).invoke(); 3869 } 3870 3871 /** 3872 * Performs the given {@linkplain ##Bulk bulk} action for each key. 3873 * 3874 * @param parallelismThreshold the (estimated) number of elements 3875 * needed for this operation to be executed in parallel 3876 * @param action the action 3877 * @since 1.8 3878 */ 3879 public void forEachKey(long parallelismThreshold, 3880 Consumer<? super K> action) { 3881 if (action == null) throw new NullPointerException(); 3882 new ForEachKeyTask<K,V> 3883 (null, batchFor(parallelismThreshold), 0, 0, table, 3884 action).invoke(); 3885 } 3886 3887 /** 3888 * Performs the given {@linkplain ##Bulk bulk} action for each non-null transformation 3889 * of each key. 3890 * 3891 * @param parallelismThreshold the (estimated) number of elements 3892 * needed for this operation to be executed in parallel 3893 * @param transformer a function returning the transformation 3894 * for an element, or null if there is no transformation (in 3895 * which case the action is not applied) 3896 * @param action the action 3897 * @param <U> the return type of the transformer 3898 * @since 1.8 3899 */ 3900 public <U> void forEachKey(long parallelismThreshold, 3901 Function<? super K, ? extends U> transformer, 3902 Consumer<? super U> action) { 3903 if (transformer == null || action == null) 3904 throw new NullPointerException(); 3905 new ForEachTransformedKeyTask<K,V,U> 3906 (null, batchFor(parallelismThreshold), 0, 0, table, 3907 transformer, action).invoke(); 3908 } 3909 3910 /** 3911 * Returns a non-null result from applying the given {@linkplain ##Bulk bulk} search 3912 * function on each key, or null if none. Upon success, 3913 * further element processing is suppressed and the results of 3914 * any other parallel invocations of the search function are 3915 * ignored. 3916 * 3917 * @param parallelismThreshold the (estimated) number of elements 3918 * needed for this operation to be executed in parallel 3919 * @param searchFunction a function returning a non-null 3920 * result on success, else null 3921 * @param <U> the return type of the search function 3922 * @return a non-null result from applying the given search 3923 * function on each key, or null if none 3924 * @since 1.8 3925 */ 3926 public <U> U searchKeys(long parallelismThreshold, 3927 Function<? super K, ? extends U> searchFunction) { 3928 if (searchFunction == null) throw new NullPointerException(); 3929 return new SearchKeysTask<K,V,U> 3930 (null, batchFor(parallelismThreshold), 0, 0, table, 3931 searchFunction, new AtomicReference<U>()).invoke(); 3932 } 3933 3934 /** 3935 * Returns the result of {@linkplain ##Bulk bulk} accumulating all keys using the given 3936 * reducer to combine values, or null if none. 3937 * 3938 * @param parallelismThreshold the (estimated) number of elements 3939 * needed for this operation to be executed in parallel 3940 * @param reducer a commutative associative combining function 3941 * @return the result of accumulating all keys using the given 3942 * reducer to combine values, or null if none 3943 * @since 1.8 3944 */ 3945 public K reduceKeys(long parallelismThreshold, 3946 BiFunction<? super K, ? super K, ? extends K> reducer) { 3947 if (reducer == null) throw new NullPointerException(); 3948 return new ReduceKeysTask<K,V> 3949 (null, batchFor(parallelismThreshold), 0, 0, table, 3950 null, reducer).invoke(); 3951 } 3952 3953 /** 3954 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 3955 * of all keys using the given reducer to combine values, or 3956 * null if none. 3957 * 3958 * @param parallelismThreshold the (estimated) number of elements 3959 * needed for this operation to be executed in parallel 3960 * @param transformer a function returning the transformation 3961 * for an element, or null if there is no transformation (in 3962 * which case it is not combined) 3963 * @param reducer a commutative associative combining function 3964 * @param <U> the return type of the transformer 3965 * @return the result of accumulating the given transformation 3966 * of all keys 3967 * @since 1.8 3968 */ 3969 public <U> U reduceKeys(long parallelismThreshold, 3970 Function<? super K, ? extends U> transformer, 3971 BiFunction<? super U, ? super U, ? extends U> reducer) { 3972 if (transformer == null || reducer == null) 3973 throw new NullPointerException(); 3974 return new MapReduceKeysTask<K,V,U> 3975 (null, batchFor(parallelismThreshold), 0, 0, table, 3976 null, transformer, reducer).invoke(); 3977 } 3978 3979 /** 3980 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 3981 * of all keys using the given reducer to combine values, and 3982 * the given basis as an identity value. 3983 * 3984 * @param parallelismThreshold the (estimated) number of elements 3985 * needed for this operation to be executed in parallel 3986 * @param transformer a function returning the transformation 3987 * for an element 3988 * @param basis the identity (initial default value) for the reduction 3989 * @param reducer a commutative associative combining function 3990 * @return the result of accumulating the given transformation 3991 * of all keys 3992 * @since 1.8 3993 */ 3994 public double reduceKeysToDouble(long parallelismThreshold, 3995 ToDoubleFunction<? super K> transformer, 3996 double basis, 3997 DoubleBinaryOperator reducer) { 3998 if (transformer == null || reducer == null) 3999 throw new NullPointerException(); 4000 return new MapReduceKeysToDoubleTask<K,V> 4001 (null, batchFor(parallelismThreshold), 0, 0, table, 4002 null, transformer, basis, reducer).invoke(); 4003 } 4004 4005 /** 4006 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4007 * of all keys using the given reducer to combine values, and 4008 * the given basis as an identity value. 4009 * 4010 * @param parallelismThreshold the (estimated) number of elements 4011 * needed for this operation to be executed in parallel 4012 * @param transformer a function returning the transformation 4013 * for an element 4014 * @param basis the identity (initial default value) for the reduction 4015 * @param reducer a commutative associative combining function 4016 * @return the result of accumulating the given transformation 4017 * of all keys 4018 * @since 1.8 4019 */ 4020 public long reduceKeysToLong(long parallelismThreshold, 4021 ToLongFunction<? super K> transformer, 4022 long basis, 4023 LongBinaryOperator reducer) { 4024 if (transformer == null || reducer == null) 4025 throw new NullPointerException(); 4026 return new MapReduceKeysToLongTask<K,V> 4027 (null, batchFor(parallelismThreshold), 0, 0, table, 4028 null, transformer, basis, reducer).invoke(); 4029 } 4030 4031 /** 4032 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4033 * of all keys using the given reducer to combine values, and 4034 * the given basis as an identity value. 4035 * 4036 * @param parallelismThreshold the (estimated) number of elements 4037 * needed for this operation to be executed in parallel 4038 * @param transformer a function returning the transformation 4039 * for an element 4040 * @param basis the identity (initial default value) for the reduction 4041 * @param reducer a commutative associative combining function 4042 * @return the result of accumulating the given transformation 4043 * of all keys 4044 * @since 1.8 4045 */ 4046 public int reduceKeysToInt(long parallelismThreshold, 4047 ToIntFunction<? super K> transformer, 4048 int basis, 4049 IntBinaryOperator reducer) { 4050 if (transformer == null || reducer == null) 4051 throw new NullPointerException(); 4052 return new MapReduceKeysToIntTask<K,V> 4053 (null, batchFor(parallelismThreshold), 0, 0, table, 4054 null, transformer, basis, reducer).invoke(); 4055 } 4056 4057 /** 4058 * Performs the given {@linkplain ##Bulk bulk} action for each value. 4059 * 4060 * @param parallelismThreshold the (estimated) number of elements 4061 * needed for this operation to be executed in parallel 4062 * @param action the action 4063 * @since 1.8 4064 */ 4065 public void forEachValue(long parallelismThreshold, 4066 Consumer<? super V> action) { 4067 if (action == null) 4068 throw new NullPointerException(); 4069 new ForEachValueTask<K,V> 4070 (null, batchFor(parallelismThreshold), 0, 0, table, 4071 action).invoke(); 4072 } 4073 4074 /** 4075 * Performs the given {@linkplain ##Bulk bulk} action for each non-null transformation 4076 * of each value. 4077 * 4078 * @param parallelismThreshold the (estimated) number of elements 4079 * needed for this operation to be executed in parallel 4080 * @param transformer a function returning the transformation 4081 * for an element, or null if there is no transformation (in 4082 * which case the action is not applied) 4083 * @param action the action 4084 * @param <U> the return type of the transformer 4085 * @since 1.8 4086 */ 4087 public <U> void forEachValue(long parallelismThreshold, 4088 Function<? super V, ? extends U> transformer, 4089 Consumer<? super U> action) { 4090 if (transformer == null || action == null) 4091 throw new NullPointerException(); 4092 new ForEachTransformedValueTask<K,V,U> 4093 (null, batchFor(parallelismThreshold), 0, 0, table, 4094 transformer, action).invoke(); 4095 } 4096 4097 /** 4098 * Returns a non-null result from {@linkplain ##Bulk bulk} applying the given search 4099 * function on each value, or null if none. Upon success, 4100 * further element processing is suppressed and the results of 4101 * any other parallel invocations of the search function are 4102 * ignored. 4103 * 4104 * @param parallelismThreshold the (estimated) number of elements 4105 * needed for this operation to be executed in parallel 4106 * @param searchFunction a function returning a non-null 4107 * result on success, else null 4108 * @param <U> the return type of the search function 4109 * @return a non-null result from applying the given search 4110 * function on each value, or null if none 4111 * @since 1.8 4112 */ 4113 public <U> U searchValues(long parallelismThreshold, 4114 Function<? super V, ? extends U> searchFunction) { 4115 if (searchFunction == null) throw new NullPointerException(); 4116 return new SearchValuesTask<K,V,U> 4117 (null, batchFor(parallelismThreshold), 0, 0, table, 4118 searchFunction, new AtomicReference<U>()).invoke(); 4119 } 4120 4121 /** 4122 * Returns the result of {@linkplain ##Bulk bulk} accumulating all values using the 4123 * given reducer to combine values, or null if none. 4124 * 4125 * @param parallelismThreshold the (estimated) number of elements 4126 * needed for this operation to be executed in parallel 4127 * @param reducer a commutative associative combining function 4128 * @return the result of accumulating all values 4129 * @since 1.8 4130 */ 4131 public V reduceValues(long parallelismThreshold, 4132 BiFunction<? super V, ? super V, ? extends V> reducer) { 4133 if (reducer == null) throw new NullPointerException(); 4134 return new ReduceValuesTask<K,V> 4135 (null, batchFor(parallelismThreshold), 0, 0, table, 4136 null, reducer).invoke(); 4137 } 4138 4139 /** 4140 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4141 * of all values using the given reducer to combine values, or 4142 * null if none. 4143 * 4144 * @param parallelismThreshold the (estimated) number of elements 4145 * needed for this operation to be executed in parallel 4146 * @param transformer a function returning the transformation 4147 * for an element, or null if there is no transformation (in 4148 * which case it is not combined) 4149 * @param reducer a commutative associative combining function 4150 * @param <U> the return type of the transformer 4151 * @return the result of accumulating the given transformation 4152 * of all values 4153 * @since 1.8 4154 */ 4155 public <U> U reduceValues(long parallelismThreshold, 4156 Function<? super V, ? extends U> transformer, 4157 BiFunction<? super U, ? super U, ? extends U> reducer) { 4158 if (transformer == null || reducer == null) 4159 throw new NullPointerException(); 4160 return new MapReduceValuesTask<K,V,U> 4161 (null, batchFor(parallelismThreshold), 0, 0, table, 4162 null, transformer, reducer).invoke(); 4163 } 4164 4165 /** 4166 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4167 * of all values using the given reducer to combine values, 4168 * and the given basis as an identity value. 4169 * 4170 * @param parallelismThreshold the (estimated) number of elements 4171 * needed for this operation to be executed in parallel 4172 * @param transformer a function returning the transformation 4173 * for an element 4174 * @param basis the identity (initial default value) for the reduction 4175 * @param reducer a commutative associative combining function 4176 * @return the result of accumulating the given transformation 4177 * of all values 4178 * @since 1.8 4179 */ 4180 public double reduceValuesToDouble(long parallelismThreshold, 4181 ToDoubleFunction<? super V> transformer, 4182 double basis, 4183 DoubleBinaryOperator reducer) { 4184 if (transformer == null || reducer == null) 4185 throw new NullPointerException(); 4186 return new MapReduceValuesToDoubleTask<K,V> 4187 (null, batchFor(parallelismThreshold), 0, 0, table, 4188 null, transformer, basis, reducer).invoke(); 4189 } 4190 4191 /** 4192 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4193 * of all values using the given reducer to combine values, 4194 * and the given basis as an identity value. 4195 * 4196 * @param parallelismThreshold the (estimated) number of elements 4197 * needed for this operation to be executed in parallel 4198 * @param transformer a function returning the transformation 4199 * for an element 4200 * @param basis the identity (initial default value) for the reduction 4201 * @param reducer a commutative associative combining function 4202 * @return the result of accumulating the given transformation 4203 * of all values 4204 * @since 1.8 4205 */ 4206 public long reduceValuesToLong(long parallelismThreshold, 4207 ToLongFunction<? super V> transformer, 4208 long basis, 4209 LongBinaryOperator reducer) { 4210 if (transformer == null || reducer == null) 4211 throw new NullPointerException(); 4212 return new MapReduceValuesToLongTask<K,V> 4213 (null, batchFor(parallelismThreshold), 0, 0, table, 4214 null, transformer, basis, reducer).invoke(); 4215 } 4216 4217 /** 4218 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4219 * of all values using the given reducer to combine values, 4220 * and the given basis as an identity value. 4221 * 4222 * @param parallelismThreshold the (estimated) number of elements 4223 * needed for this operation to be executed in parallel 4224 * @param transformer a function returning the transformation 4225 * for an element 4226 * @param basis the identity (initial default value) for the reduction 4227 * @param reducer a commutative associative combining function 4228 * @return the result of accumulating the given transformation 4229 * of all values 4230 * @since 1.8 4231 */ 4232 public int reduceValuesToInt(long parallelismThreshold, 4233 ToIntFunction<? super V> transformer, 4234 int basis, 4235 IntBinaryOperator reducer) { 4236 if (transformer == null || reducer == null) 4237 throw new NullPointerException(); 4238 return new MapReduceValuesToIntTask<K,V> 4239 (null, batchFor(parallelismThreshold), 0, 0, table, 4240 null, transformer, basis, reducer).invoke(); 4241 } 4242 4243 /** 4244 * Performs the given {@linkplain ##Bulk bulk} action for each entry. 4245 * 4246 * @param parallelismThreshold the (estimated) number of elements 4247 * needed for this operation to be executed in parallel 4248 * @param action the action 4249 * @since 1.8 4250 */ 4251 public void forEachEntry(long parallelismThreshold, 4252 Consumer<? super Map.Entry<K,V>> action) { 4253 if (action == null) throw new NullPointerException(); 4254 new ForEachEntryTask<K,V>(null, batchFor(parallelismThreshold), 0, 0, table, 4255 action).invoke(); 4256 } 4257 4258 /** 4259 * Performs the given {@linkplain ##Bulk bulk} action for each non-null transformation 4260 * of each entry. 4261 * 4262 * @param parallelismThreshold the (estimated) number of elements 4263 * needed for this operation to be executed in parallel 4264 * @param transformer a function returning the transformation 4265 * for an element, or null if there is no transformation (in 4266 * which case the action is not applied) 4267 * @param action the action 4268 * @param <U> the return type of the transformer 4269 * @since 1.8 4270 */ 4271 public <U> void forEachEntry(long parallelismThreshold, 4272 Function<Map.Entry<K,V>, ? extends U> transformer, 4273 Consumer<? super U> action) { 4274 if (transformer == null || action == null) 4275 throw new NullPointerException(); 4276 new ForEachTransformedEntryTask<K,V,U> 4277 (null, batchFor(parallelismThreshold), 0, 0, table, 4278 transformer, action).invoke(); 4279 } 4280 4281 /** 4282 * Returns a non-null result from {@linkplain ##Bulk bulk} applying the given search 4283 * function on each entry, or null if none. Upon success, 4284 * further element processing is suppressed and the results of 4285 * any other parallel invocations of the search function are 4286 * ignored. 4287 * 4288 * @param parallelismThreshold the (estimated) number of elements 4289 * needed for this operation to be executed in parallel 4290 * @param searchFunction a function returning a non-null 4291 * result on success, else null 4292 * @param <U> the return type of the search function 4293 * @return a non-null result from applying the given search 4294 * function on each entry, or null if none 4295 * @since 1.8 4296 */ 4297 public <U> U searchEntries(long parallelismThreshold, 4298 Function<Map.Entry<K,V>, ? extends U> searchFunction) { 4299 if (searchFunction == null) throw new NullPointerException(); 4300 return new SearchEntriesTask<K,V,U> 4301 (null, batchFor(parallelismThreshold), 0, 0, table, 4302 searchFunction, new AtomicReference<U>()).invoke(); 4303 } 4304 4305 /** 4306 * Returns the result of {@linkplain ##Bulk bulk} accumulating all entries using the 4307 * given reducer to combine values, or null if none. 4308 * 4309 * @param parallelismThreshold the (estimated) number of elements 4310 * needed for this operation to be executed in parallel 4311 * @param reducer a commutative associative combining function 4312 * @return the result of accumulating all entries 4313 * @since 1.8 4314 */ 4315 public Map.Entry<K,V> reduceEntries(long parallelismThreshold, 4316 BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { 4317 if (reducer == null) throw new NullPointerException(); 4318 return new ReduceEntriesTask<K,V> 4319 (null, batchFor(parallelismThreshold), 0, 0, table, 4320 null, reducer).invoke(); 4321 } 4322 4323 /** 4324 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4325 * of all entries using the given reducer to combine values, 4326 * or null if none. 4327 * 4328 * @param parallelismThreshold the (estimated) number of elements 4329 * needed for this operation to be executed in parallel 4330 * @param transformer a function returning the transformation 4331 * for an element, or null if there is no transformation (in 4332 * which case it is not combined) 4333 * @param reducer a commutative associative combining function 4334 * @param <U> the return type of the transformer 4335 * @return the result of accumulating the given transformation 4336 * of all entries 4337 * @since 1.8 4338 */ 4339 public <U> U reduceEntries(long parallelismThreshold, 4340 Function<Map.Entry<K,V>, ? extends U> transformer, 4341 BiFunction<? super U, ? super U, ? extends U> reducer) { 4342 if (transformer == null || reducer == null) 4343 throw new NullPointerException(); 4344 return new MapReduceEntriesTask<K,V,U> 4345 (null, batchFor(parallelismThreshold), 0, 0, table, 4346 null, transformer, reducer).invoke(); 4347 } 4348 4349 /** 4350 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4351 * of all entries using the given reducer to combine values, 4352 * and the given basis as an identity value. 4353 * 4354 * @param parallelismThreshold the (estimated) number of elements 4355 * needed for this operation to be executed in parallel 4356 * @param transformer a function returning the transformation 4357 * for an element 4358 * @param basis the identity (initial default value) for the reduction 4359 * @param reducer a commutative associative combining function 4360 * @return the result of accumulating the given transformation 4361 * of all entries 4362 * @since 1.8 4363 */ 4364 public double reduceEntriesToDouble(long parallelismThreshold, 4365 ToDoubleFunction<Map.Entry<K,V>> transformer, 4366 double basis, 4367 DoubleBinaryOperator reducer) { 4368 if (transformer == null || reducer == null) 4369 throw new NullPointerException(); 4370 return new MapReduceEntriesToDoubleTask<K,V> 4371 (null, batchFor(parallelismThreshold), 0, 0, table, 4372 null, transformer, basis, reducer).invoke(); 4373 } 4374 4375 /** 4376 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4377 * of all entries using the given reducer to combine values, 4378 * and the given basis as an identity value. 4379 * 4380 * @param parallelismThreshold the (estimated) number of elements 4381 * needed for this operation to be executed in parallel 4382 * @param transformer a function returning the transformation 4383 * for an element 4384 * @param basis the identity (initial default value) for the reduction 4385 * @param reducer a commutative associative combining function 4386 * @return the result of accumulating the given transformation 4387 * of all entries 4388 * @since 1.8 4389 */ 4390 public long reduceEntriesToLong(long parallelismThreshold, 4391 ToLongFunction<Map.Entry<K,V>> transformer, 4392 long basis, 4393 LongBinaryOperator reducer) { 4394 if (transformer == null || reducer == null) 4395 throw new NullPointerException(); 4396 return new MapReduceEntriesToLongTask<K,V> 4397 (null, batchFor(parallelismThreshold), 0, 0, table, 4398 null, transformer, basis, reducer).invoke(); 4399 } 4400 4401 /** 4402 * Returns the result of {@linkplain ##Bulk bulk} accumulating the given transformation 4403 * of all entries using the given reducer to combine values, 4404 * and the given basis as an identity value. 4405 * 4406 * @param parallelismThreshold the (estimated) number of elements 4407 * needed for this operation to be executed in parallel 4408 * @param transformer a function returning the transformation 4409 * for an element 4410 * @param basis the identity (initial default value) for the reduction 4411 * @param reducer a commutative associative combining function 4412 * @return the result of accumulating the given transformation 4413 * of all entries 4414 * @since 1.8 4415 */ 4416 public int reduceEntriesToInt(long parallelismThreshold, 4417 ToIntFunction<Map.Entry<K,V>> transformer, 4418 int basis, 4419 IntBinaryOperator reducer) { 4420 if (transformer == null || reducer == null) 4421 throw new NullPointerException(); 4422 return new MapReduceEntriesToIntTask<K,V> 4423 (null, batchFor(parallelismThreshold), 0, 0, table, 4424 null, transformer, basis, reducer).invoke(); 4425 } 4426 4427 4428 /* ----------------Views -------------- */ 4429 4430 /** 4431 * Base class for views. 4432 */ 4433 abstract static sealed class CollectionView<K,V,E> 4434 implements Collection<E>, java.io.Serializable permits EntrySetView, KeySetView, ValuesView { 4435 private static final long serialVersionUID = 7249069246763182397L; 4436 final ConcurrentHashMap<K,V> map; 4437 CollectionView(ConcurrentHashMap<K,V> map) { this.map = map; } 4438 4439 /** 4440 * Returns the map backing this view. 4441 * 4442 * @return the map backing this view 4443 */ 4444 public ConcurrentHashMap<K,V> getMap() { return map; } 4445 4446 /** 4447 * Removes all of the elements from this view, by removing all 4448 * the mappings from the map backing this view. 4449 */ 4450 public final void clear() { map.clear(); } 4451 public final int size() { return map.size(); } 4452 public final boolean isEmpty() { return map.isEmpty(); } 4453 4454 // implementations below rely on concrete classes supplying these 4455 // abstract methods 4456 /** 4457 * Returns an iterator over the elements in this collection. 4458 * 4459 * <p>The returned iterator is 4460 * <a href="package-summary.html#Weakly"><i>weakly consistent</i></a>. 4461 * 4462 * @return an iterator over the elements in this collection 4463 */ 4464 public abstract Iterator<E> iterator(); 4465 public abstract boolean contains(Object o); 4466 public abstract boolean remove(Object o); 4467 4468 private static final String OOME_MSG = "Required array size too large"; 4469 4470 public final Object[] toArray() { 4471 long sz = map.mappingCount(); 4472 if (sz > MAX_ARRAY_SIZE) 4473 throw new OutOfMemoryError(OOME_MSG); 4474 int n = (int)sz; 4475 Object[] r = new Object[n]; 4476 int i = 0; 4477 for (E e : this) { 4478 if (i == n) { 4479 if (n >= MAX_ARRAY_SIZE) 4480 throw new OutOfMemoryError(OOME_MSG); 4481 if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) 4482 n = MAX_ARRAY_SIZE; 4483 else 4484 n += (n >>> 1) + 1; 4485 r = Arrays.copyOf(r, n); 4486 } 4487 r[i++] = e; 4488 } 4489 return (i == n) ? r : Arrays.copyOf(r, i); 4490 } 4491 4492 @SuppressWarnings("unchecked") 4493 public final <T> T[] toArray(T[] a) { 4494 long sz = map.mappingCount(); 4495 if (sz > MAX_ARRAY_SIZE) 4496 throw new OutOfMemoryError(OOME_MSG); 4497 int m = (int)sz; 4498 T[] r = (a.length >= m) ? a : 4499 (T[])java.lang.reflect.Array 4500 .newInstance(a.getClass().getComponentType(), m); 4501 int n = r.length; 4502 int i = 0; 4503 for (E e : this) { 4504 if (i == n) { 4505 if (n >= MAX_ARRAY_SIZE) 4506 throw new OutOfMemoryError(OOME_MSG); 4507 if (n >= MAX_ARRAY_SIZE - (MAX_ARRAY_SIZE >>> 1) - 1) 4508 n = MAX_ARRAY_SIZE; 4509 else 4510 n += (n >>> 1) + 1; 4511 r = Arrays.copyOf(r, n); 4512 } 4513 r[i++] = (T)e; 4514 } 4515 if (a == r && i < n) { 4516 r[i] = null; // null-terminate 4517 return r; 4518 } 4519 return (i == n) ? r : Arrays.copyOf(r, i); 4520 } 4521 4522 /** 4523 * Returns a string representation of this collection. 4524 * The string representation consists of the string representations 4525 * of the collection's elements in the order they are returned by 4526 * its iterator, enclosed in square brackets ({@code "[]"}). 4527 * Adjacent elements are separated by the characters {@code ", "} 4528 * (comma and space). Elements are converted to strings as by 4529 * {@link String#valueOf(Object)}. 4530 * 4531 * @return a string representation of this collection 4532 */ 4533 public final String toString() { 4534 StringBuilder sb = new StringBuilder(); 4535 sb.append('['); 4536 Iterator<E> it = iterator(); 4537 if (it.hasNext()) { 4538 for (;;) { 4539 Object e = it.next(); 4540 sb.append(e == this ? "(this Collection)" : e); 4541 if (!it.hasNext()) 4542 break; 4543 sb.append(',').append(' '); 4544 } 4545 } 4546 return sb.append(']').toString(); 4547 } 4548 4549 public final boolean containsAll(Collection<?> c) { 4550 if (c != this) { 4551 for (Object e : c) { 4552 if (e == null || !contains(e)) 4553 return false; 4554 } 4555 } 4556 return true; 4557 } 4558 4559 public boolean removeAll(Collection<?> c) { 4560 if (c == null) throw new NullPointerException(); 4561 boolean modified = false; 4562 // Use (c instanceof Set) as a hint that lookup in c is as 4563 // efficient as this view 4564 Node<K,V>[] t; 4565 if ((t = map.table) == null) { 4566 return false; 4567 } else if (c instanceof Set<?> && c.size() > t.length) { 4568 for (Iterator<?> it = iterator(); it.hasNext(); ) { 4569 if (c.contains(it.next())) { 4570 it.remove(); 4571 modified = true; 4572 } 4573 } 4574 } else { 4575 for (Object e : c) 4576 modified |= remove(e); 4577 } 4578 return modified; 4579 } 4580 4581 public final boolean retainAll(Collection<?> c) { 4582 if (c == null) throw new NullPointerException(); 4583 boolean modified = false; 4584 for (Iterator<E> it = iterator(); it.hasNext();) { 4585 if (!c.contains(it.next())) { 4586 it.remove(); 4587 modified = true; 4588 } 4589 } 4590 return modified; 4591 } 4592 4593 } 4594 4595 /** 4596 * A view of a ConcurrentHashMap as a {@link Set} of keys, in 4597 * which additions may optionally be enabled by mapping to a 4598 * common value. This class cannot be directly instantiated. 4599 * See {@link #keySet() keySet()}, 4600 * {@link #keySet(Object) keySet(V)}, 4601 * {@link #newKeySet() newKeySet()}, 4602 * {@link #newKeySet(int) newKeySet(int)}. 4603 * 4604 * @param <K> the type of keys 4605 * @param <V> the type of values in the backing map 4606 * 4607 * @since 1.8 4608 */ 4609 public static final class KeySetView<K,V> extends CollectionView<K,V,K> 4610 implements Set<K>, java.io.Serializable { 4611 private static final long serialVersionUID = 7249069246763182397L; 4612 /** @serial */ 4613 @SuppressWarnings("serial") // Conditionally serializable 4614 private final V value; 4615 KeySetView(ConcurrentHashMap<K,V> map, V value) { // non-public 4616 super(map); 4617 this.value = value; 4618 } 4619 4620 /** 4621 * Returns the default mapped value for additions, 4622 * or {@code null} if additions are not supported. 4623 * 4624 * @return the default mapped value for additions, or {@code null} 4625 * if not supported 4626 */ 4627 public V getMappedValue() { return value; } 4628 4629 /** 4630 * {@inheritDoc} 4631 * @throws NullPointerException if the specified key is null 4632 */ 4633 public boolean contains(Object o) { return map.containsKey(o); } 4634 4635 /** 4636 * Removes the key from this map view, by removing the key (and its 4637 * corresponding value) from the backing map. This method does 4638 * nothing if the key is not in the map. 4639 * 4640 * @param o the key to be removed from the backing map 4641 * @return {@code true} if the backing map contained the specified key 4642 * @throws NullPointerException if the specified key is null 4643 */ 4644 public boolean remove(Object o) { return map.remove(o) != null; } 4645 4646 /** 4647 * @return an iterator over the keys of the backing map 4648 */ 4649 public Iterator<K> iterator() { 4650 Node<K,V>[] t; 4651 ConcurrentHashMap<K,V> m = map; 4652 int f = (t = m.table) == null ? 0 : t.length; 4653 return new KeyIterator<K,V>(t, f, 0, f, m); 4654 } 4655 4656 /** 4657 * Adds the specified key to this set view by mapping the key to 4658 * the default mapped value in the backing map, if defined. 4659 * 4660 * @param e key to be added 4661 * @return {@code true} if this set changed as a result of the call 4662 * @throws NullPointerException if the specified key is null 4663 * @throws UnsupportedOperationException if no default mapped value 4664 * for additions was provided 4665 */ 4666 public boolean add(K e) { 4667 V v; 4668 if ((v = value) == null) 4669 throw new UnsupportedOperationException(); 4670 return map.putVal(e, v, true) == null; 4671 } 4672 4673 /** 4674 * Adds all of the elements in the specified collection to this set, 4675 * as if by calling {@link #add} on each one. 4676 * 4677 * @param c the elements to be inserted into this set 4678 * @return {@code true} if this set changed as a result of the call 4679 * @throws NullPointerException if the collection or any of its 4680 * elements are {@code null} 4681 * @throws UnsupportedOperationException if no default mapped value 4682 * for additions was provided 4683 */ 4684 public boolean addAll(Collection<? extends K> c) { 4685 boolean added = false; 4686 V v; 4687 if ((v = value) == null) 4688 throw new UnsupportedOperationException(); 4689 for (K e : c) { 4690 if (map.putVal(e, v, true) == null) 4691 added = true; 4692 } 4693 return added; 4694 } 4695 4696 public int hashCode() { 4697 int h = 0; 4698 for (K e : this) 4699 h += e.hashCode(); 4700 return h; 4701 } 4702 4703 public boolean equals(Object o) { 4704 Set<?> c; 4705 return ((o instanceof Set) && 4706 ((c = (Set<?>)o) == this || 4707 (containsAll(c) && c.containsAll(this)))); 4708 } 4709 4710 public Spliterator<K> spliterator() { 4711 Node<K,V>[] t; 4712 ConcurrentHashMap<K,V> m = map; 4713 long n = m.sumCount(); 4714 int f = (t = m.table) == null ? 0 : t.length; 4715 return new KeySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); 4716 } 4717 4718 public void forEach(Consumer<? super K> action) { 4719 if (action == null) throw new NullPointerException(); 4720 Node<K,V>[] t; 4721 if ((t = map.table) != null) { 4722 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4723 for (Node<K,V> p; (p = it.advance()) != null; ) 4724 action.accept(p.key); 4725 } 4726 } 4727 } 4728 4729 /** 4730 * A view of a ConcurrentHashMap as a {@link Collection} of 4731 * values, in which additions are disabled. This class cannot be 4732 * directly instantiated. See {@link #values()}. 4733 */ 4734 static final class ValuesView<K,V> extends CollectionView<K,V,V> 4735 implements Collection<V>, java.io.Serializable { 4736 private static final long serialVersionUID = 2249069246763182397L; 4737 ValuesView(ConcurrentHashMap<K,V> map) { super(map); } 4738 public final boolean contains(Object o) { 4739 return map.containsValue(o); 4740 } 4741 4742 public final boolean remove(Object o) { 4743 if (o != null) { 4744 for (Iterator<V> it = iterator(); it.hasNext();) { 4745 if (o.equals(it.next())) { 4746 it.remove(); 4747 return true; 4748 } 4749 } 4750 } 4751 return false; 4752 } 4753 4754 public final Iterator<V> iterator() { 4755 ConcurrentHashMap<K,V> m = map; 4756 Node<K,V>[] t; 4757 int f = (t = m.table) == null ? 0 : t.length; 4758 return new ValueIterator<K,V>(t, f, 0, f, m); 4759 } 4760 4761 public final boolean add(V e) { 4762 throw new UnsupportedOperationException(); 4763 } 4764 public final boolean addAll(Collection<? extends V> c) { 4765 throw new UnsupportedOperationException(); 4766 } 4767 4768 @Override public boolean removeAll(Collection<?> c) { 4769 if (c == null) throw new NullPointerException(); 4770 boolean modified = false; 4771 for (Iterator<V> it = iterator(); it.hasNext();) { 4772 if (c.contains(it.next())) { 4773 it.remove(); 4774 modified = true; 4775 } 4776 } 4777 return modified; 4778 } 4779 4780 public boolean removeIf(Predicate<? super V> filter) { 4781 return map.removeValueIf(filter); 4782 } 4783 4784 public Spliterator<V> spliterator() { 4785 Node<K,V>[] t; 4786 ConcurrentHashMap<K,V> m = map; 4787 long n = m.sumCount(); 4788 int f = (t = m.table) == null ? 0 : t.length; 4789 return new ValueSpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n); 4790 } 4791 4792 public void forEach(Consumer<? super V> action) { 4793 if (action == null) throw new NullPointerException(); 4794 Node<K,V>[] t; 4795 if ((t = map.table) != null) { 4796 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4797 for (Node<K,V> p; (p = it.advance()) != null; ) 4798 action.accept(p.val); 4799 } 4800 } 4801 } 4802 4803 /** 4804 * A view of a ConcurrentHashMap as a {@link Set} of (key, value) 4805 * entries. This class cannot be directly instantiated. See 4806 * {@link #entrySet()}. 4807 */ 4808 static final class EntrySetView<K,V> extends CollectionView<K,V,Map.Entry<K,V>> 4809 implements Set<Map.Entry<K,V>>, java.io.Serializable { 4810 private static final long serialVersionUID = 2249069246763182397L; 4811 EntrySetView(ConcurrentHashMap<K,V> map) { super(map); } 4812 4813 public boolean contains(Object o) { 4814 Object k, v, r; Map.Entry<?,?> e; 4815 return ((o instanceof Map.Entry) && 4816 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 4817 (r = map.get(k)) != null && 4818 (v = e.getValue()) != null && 4819 (v == r || v.equals(r))); 4820 } 4821 4822 public boolean remove(Object o) { 4823 Object k, v; Map.Entry<?,?> e; 4824 return ((o instanceof Map.Entry) && 4825 (k = (e = (Map.Entry<?,?>)o).getKey()) != null && 4826 (v = e.getValue()) != null && 4827 map.remove(k, v)); 4828 } 4829 4830 /** 4831 * @return an iterator over the entries of the backing map 4832 */ 4833 public Iterator<Map.Entry<K,V>> iterator() { 4834 ConcurrentHashMap<K,V> m = map; 4835 Node<K,V>[] t; 4836 int f = (t = m.table) == null ? 0 : t.length; 4837 return new EntryIterator<K,V>(t, f, 0, f, m); 4838 } 4839 4840 public boolean add(Entry<K,V> e) { 4841 return map.putVal(e.getKey(), e.getValue(), false) == null; 4842 } 4843 4844 public boolean addAll(Collection<? extends Entry<K,V>> c) { 4845 boolean added = false; 4846 for (Entry<K,V> e : c) { 4847 if (add(e)) 4848 added = true; 4849 } 4850 return added; 4851 } 4852 4853 public boolean removeIf(Predicate<? super Entry<K,V>> filter) { 4854 return map.removeEntryIf(filter); 4855 } 4856 4857 public final int hashCode() { 4858 int h = 0; 4859 Node<K,V>[] t; 4860 if ((t = map.table) != null) { 4861 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4862 for (Node<K,V> p; (p = it.advance()) != null; ) { 4863 h += p.hashCode(); 4864 } 4865 } 4866 return h; 4867 } 4868 4869 public final boolean equals(Object o) { 4870 Set<?> c; 4871 return ((o instanceof Set) && 4872 ((c = (Set<?>)o) == this || 4873 (containsAll(c) && c.containsAll(this)))); 4874 } 4875 4876 public Spliterator<Map.Entry<K,V>> spliterator() { 4877 Node<K,V>[] t; 4878 ConcurrentHashMap<K,V> m = map; 4879 long n = m.sumCount(); 4880 int f = (t = m.table) == null ? 0 : t.length; 4881 return new EntrySpliterator<K,V>(t, f, 0, f, n < 0L ? 0L : n, m); 4882 } 4883 4884 public void forEach(Consumer<? super Map.Entry<K,V>> action) { 4885 if (action == null) throw new NullPointerException(); 4886 Node<K,V>[] t; 4887 if ((t = map.table) != null) { 4888 Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length); 4889 for (Node<K,V> p; (p = it.advance()) != null; ) 4890 action.accept(new MapEntry<K,V>(p.key, p.val, map)); 4891 } 4892 } 4893 4894 } 4895 4896 // ------------------------------------------------------- 4897 4898 /** 4899 * Base class for bulk tasks. Repeats some fields and code from 4900 * class Traverser, because we need to subclass CountedCompleter. 4901 */ 4902 @SuppressWarnings("serial") 4903 abstract static class BulkTask<K,V,R> extends CountedCompleter<R> { 4904 Node<K,V>[] tab; // same as Traverser 4905 Node<K,V> next; 4906 TableStack<K,V> stack, spare; 4907 int index; 4908 int baseIndex; 4909 int baseLimit; 4910 final int baseSize; 4911 int batch; // split control 4912 4913 BulkTask(BulkTask<K,V,?> par, int b, int i, int f, Node<K,V>[] t) { 4914 super(par); 4915 this.batch = b; 4916 this.index = this.baseIndex = i; 4917 if ((this.tab = t) == null) 4918 this.baseSize = this.baseLimit = 0; 4919 else if (par == null) 4920 this.baseSize = this.baseLimit = t.length; 4921 else { 4922 this.baseLimit = f; 4923 this.baseSize = par.baseSize; 4924 } 4925 } 4926 4927 /** 4928 * Same as Traverser version. 4929 */ 4930 final Node<K,V> advance() { 4931 Node<K,V> e; 4932 if ((e = next) != null) 4933 e = e.next; 4934 for (;;) { 4935 Node<K,V>[] t; int i, n; 4936 if (e != null) 4937 return next = e; 4938 if (baseIndex >= baseLimit || (t = tab) == null || 4939 (n = t.length) <= (i = index) || i < 0) 4940 return next = null; 4941 if ((e = tabAt(t, i)) != null && e.hash < 0) { 4942 if (e instanceof ForwardingNode) { 4943 tab = ((ForwardingNode<K,V>)e).nextTable; 4944 e = null; 4945 pushState(t, i, n); 4946 continue; 4947 } 4948 else if (e instanceof TreeBin) 4949 e = ((TreeBin<K,V>)e).first; 4950 else 4951 e = null; 4952 } 4953 if (stack != null) 4954 recoverState(n); 4955 else if ((index = i + baseSize) >= n) 4956 index = ++baseIndex; 4957 } 4958 } 4959 4960 private void pushState(Node<K,V>[] t, int i, int n) { 4961 TableStack<K,V> s = spare; 4962 if (s != null) 4963 spare = s.next; 4964 else 4965 s = new TableStack<K,V>(); 4966 s.tab = t; 4967 s.length = n; 4968 s.index = i; 4969 s.next = stack; 4970 stack = s; 4971 } 4972 4973 private void recoverState(int n) { 4974 TableStack<K,V> s; int len; 4975 while ((s = stack) != null && (index += (len = s.length)) >= n) { 4976 n = len; 4977 index = s.index; 4978 tab = s.tab; 4979 s.tab = null; 4980 TableStack<K,V> next = s.next; 4981 s.next = spare; // save for reuse 4982 stack = next; 4983 spare = s; 4984 } 4985 if (s == null && (index += baseSize) >= n) 4986 index = ++baseIndex; 4987 } 4988 } 4989 4990 /* 4991 * Task classes. Coded in a regular but ugly format/style to 4992 * simplify checks that each variant differs in the right way from 4993 * others. The null screenings exist because compilers cannot tell 4994 * that we've already null-checked task arguments, so we force 4995 * simplest hoisted bypass to help avoid convoluted traps. 4996 */ 4997 @SuppressWarnings("serial") 4998 static final class ForEachKeyTask<K,V> 4999 extends BulkTask<K,V,Void> { 5000 final Consumer<? super K> action; 5001 ForEachKeyTask 5002 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5003 Consumer<? super K> action) { 5004 super(p, b, i, f, t); 5005 this.action = action; 5006 } 5007 public final void compute() { 5008 final Consumer<? super K> action; 5009 if ((action = this.action) != null) { 5010 for (int i = baseIndex, f, h; batch > 0 && 5011 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5012 addToPendingCount(1); 5013 new ForEachKeyTask<K,V> 5014 (this, batch >>>= 1, baseLimit = h, f, tab, 5015 action).fork(); 5016 } 5017 for (Node<K,V> p; (p = advance()) != null;) 5018 action.accept(p.key); 5019 propagateCompletion(); 5020 } 5021 } 5022 } 5023 5024 @SuppressWarnings("serial") 5025 static final class ForEachValueTask<K,V> 5026 extends BulkTask<K,V,Void> { 5027 final Consumer<? super V> action; 5028 ForEachValueTask 5029 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5030 Consumer<? super V> action) { 5031 super(p, b, i, f, t); 5032 this.action = action; 5033 } 5034 public final void compute() { 5035 final Consumer<? super V> action; 5036 if ((action = this.action) != null) { 5037 for (int i = baseIndex, f, h; batch > 0 && 5038 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5039 addToPendingCount(1); 5040 new ForEachValueTask<K,V> 5041 (this, batch >>>= 1, baseLimit = h, f, tab, 5042 action).fork(); 5043 } 5044 for (Node<K,V> p; (p = advance()) != null;) 5045 action.accept(p.val); 5046 propagateCompletion(); 5047 } 5048 } 5049 } 5050 5051 @SuppressWarnings("serial") 5052 static final class ForEachEntryTask<K,V> 5053 extends BulkTask<K,V,Void> { 5054 final Consumer<? super Entry<K,V>> action; 5055 ForEachEntryTask 5056 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5057 Consumer<? super Entry<K,V>> action) { 5058 super(p, b, i, f, t); 5059 this.action = action; 5060 } 5061 public final void compute() { 5062 final Consumer<? super Entry<K,V>> action; 5063 if ((action = this.action) != null) { 5064 for (int i = baseIndex, f, h; batch > 0 && 5065 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5066 addToPendingCount(1); 5067 new ForEachEntryTask<K,V> 5068 (this, batch >>>= 1, baseLimit = h, f, tab, 5069 action).fork(); 5070 } 5071 for (Node<K,V> p; (p = advance()) != null; ) 5072 action.accept(p); 5073 propagateCompletion(); 5074 } 5075 } 5076 } 5077 5078 @SuppressWarnings("serial") 5079 static final class ForEachMappingTask<K,V> 5080 extends BulkTask<K,V,Void> { 5081 final BiConsumer<? super K, ? super V> action; 5082 ForEachMappingTask 5083 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5084 BiConsumer<? super K,? super V> action) { 5085 super(p, b, i, f, t); 5086 this.action = action; 5087 } 5088 public final void compute() { 5089 final BiConsumer<? super K, ? super V> action; 5090 if ((action = this.action) != null) { 5091 for (int i = baseIndex, f, h; batch > 0 && 5092 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5093 addToPendingCount(1); 5094 new ForEachMappingTask<K,V> 5095 (this, batch >>>= 1, baseLimit = h, f, tab, 5096 action).fork(); 5097 } 5098 for (Node<K,V> p; (p = advance()) != null; ) 5099 action.accept(p.key, p.val); 5100 propagateCompletion(); 5101 } 5102 } 5103 } 5104 5105 @SuppressWarnings("serial") 5106 static final class ForEachTransformedKeyTask<K,V,U> 5107 extends BulkTask<K,V,Void> { 5108 final Function<? super K, ? extends U> transformer; 5109 final Consumer<? super U> action; 5110 ForEachTransformedKeyTask 5111 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5112 Function<? super K, ? extends U> transformer, Consumer<? super U> action) { 5113 super(p, b, i, f, t); 5114 this.transformer = transformer; this.action = action; 5115 } 5116 public final void compute() { 5117 final Function<? super K, ? extends U> transformer; 5118 final Consumer<? super U> action; 5119 if ((transformer = this.transformer) != null && 5120 (action = this.action) != null) { 5121 for (int i = baseIndex, f, h; batch > 0 && 5122 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5123 addToPendingCount(1); 5124 new ForEachTransformedKeyTask<K,V,U> 5125 (this, batch >>>= 1, baseLimit = h, f, tab, 5126 transformer, action).fork(); 5127 } 5128 for (Node<K,V> p; (p = advance()) != null; ) { 5129 U u; 5130 if ((u = transformer.apply(p.key)) != null) 5131 action.accept(u); 5132 } 5133 propagateCompletion(); 5134 } 5135 } 5136 } 5137 5138 @SuppressWarnings("serial") 5139 static final class ForEachTransformedValueTask<K,V,U> 5140 extends BulkTask<K,V,Void> { 5141 final Function<? super V, ? extends U> transformer; 5142 final Consumer<? super U> action; 5143 ForEachTransformedValueTask 5144 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5145 Function<? super V, ? extends U> transformer, Consumer<? super U> action) { 5146 super(p, b, i, f, t); 5147 this.transformer = transformer; this.action = action; 5148 } 5149 public final void compute() { 5150 final Function<? super V, ? extends U> transformer; 5151 final Consumer<? super U> action; 5152 if ((transformer = this.transformer) != null && 5153 (action = this.action) != null) { 5154 for (int i = baseIndex, f, h; batch > 0 && 5155 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5156 addToPendingCount(1); 5157 new ForEachTransformedValueTask<K,V,U> 5158 (this, batch >>>= 1, baseLimit = h, f, tab, 5159 transformer, action).fork(); 5160 } 5161 for (Node<K,V> p; (p = advance()) != null; ) { 5162 U u; 5163 if ((u = transformer.apply(p.val)) != null) 5164 action.accept(u); 5165 } 5166 propagateCompletion(); 5167 } 5168 } 5169 } 5170 5171 @SuppressWarnings("serial") 5172 static final class ForEachTransformedEntryTask<K,V,U> 5173 extends BulkTask<K,V,Void> { 5174 final Function<Map.Entry<K,V>, ? extends U> transformer; 5175 final Consumer<? super U> action; 5176 ForEachTransformedEntryTask 5177 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5178 Function<Map.Entry<K,V>, ? extends U> transformer, Consumer<? super U> action) { 5179 super(p, b, i, f, t); 5180 this.transformer = transformer; this.action = action; 5181 } 5182 public final void compute() { 5183 final Function<Map.Entry<K,V>, ? extends U> transformer; 5184 final Consumer<? super U> action; 5185 if ((transformer = this.transformer) != null && 5186 (action = this.action) != null) { 5187 for (int i = baseIndex, f, h; batch > 0 && 5188 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5189 addToPendingCount(1); 5190 new ForEachTransformedEntryTask<K,V,U> 5191 (this, batch >>>= 1, baseLimit = h, f, tab, 5192 transformer, action).fork(); 5193 } 5194 for (Node<K,V> p; (p = advance()) != null; ) { 5195 U u; 5196 if ((u = transformer.apply(p)) != null) 5197 action.accept(u); 5198 } 5199 propagateCompletion(); 5200 } 5201 } 5202 } 5203 5204 @SuppressWarnings("serial") 5205 static final class ForEachTransformedMappingTask<K,V,U> 5206 extends BulkTask<K,V,Void> { 5207 final BiFunction<? super K, ? super V, ? extends U> transformer; 5208 final Consumer<? super U> action; 5209 ForEachTransformedMappingTask 5210 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5211 BiFunction<? super K, ? super V, ? extends U> transformer, 5212 Consumer<? super U> action) { 5213 super(p, b, i, f, t); 5214 this.transformer = transformer; this.action = action; 5215 } 5216 public final void compute() { 5217 final BiFunction<? super K, ? super V, ? extends U> transformer; 5218 final Consumer<? super U> action; 5219 if ((transformer = this.transformer) != null && 5220 (action = this.action) != null) { 5221 for (int i = baseIndex, f, h; batch > 0 && 5222 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5223 addToPendingCount(1); 5224 new ForEachTransformedMappingTask<K,V,U> 5225 (this, batch >>>= 1, baseLimit = h, f, tab, 5226 transformer, action).fork(); 5227 } 5228 for (Node<K,V> p; (p = advance()) != null; ) { 5229 U u; 5230 if ((u = transformer.apply(p.key, p.val)) != null) 5231 action.accept(u); 5232 } 5233 propagateCompletion(); 5234 } 5235 } 5236 } 5237 5238 @SuppressWarnings("serial") 5239 static final class SearchKeysTask<K,V,U> 5240 extends BulkTask<K,V,U> { 5241 final Function<? super K, ? extends U> searchFunction; 5242 final AtomicReference<U> result; 5243 SearchKeysTask 5244 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5245 Function<? super K, ? extends U> searchFunction, 5246 AtomicReference<U> result) { 5247 super(p, b, i, f, t); 5248 this.searchFunction = searchFunction; this.result = result; 5249 } 5250 public final U getRawResult() { return result.get(); } 5251 public final void compute() { 5252 final Function<? super K, ? extends U> searchFunction; 5253 final AtomicReference<U> result; 5254 if ((searchFunction = this.searchFunction) != null && 5255 (result = this.result) != null) { 5256 for (int i = baseIndex, f, h; batch > 0 && 5257 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5258 if (result.get() != null) 5259 return; 5260 addToPendingCount(1); 5261 new SearchKeysTask<K,V,U> 5262 (this, batch >>>= 1, baseLimit = h, f, tab, 5263 searchFunction, result).fork(); 5264 } 5265 while (result.get() == null) { 5266 U u; 5267 Node<K,V> p; 5268 if ((p = advance()) == null) { 5269 propagateCompletion(); 5270 break; 5271 } 5272 if ((u = searchFunction.apply(p.key)) != null) { 5273 if (result.compareAndSet(null, u)) 5274 quietlyCompleteRoot(); 5275 break; 5276 } 5277 } 5278 } 5279 } 5280 } 5281 5282 @SuppressWarnings("serial") 5283 static final class SearchValuesTask<K,V,U> 5284 extends BulkTask<K,V,U> { 5285 final Function<? super V, ? extends U> searchFunction; 5286 final AtomicReference<U> result; 5287 SearchValuesTask 5288 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5289 Function<? super V, ? extends U> searchFunction, 5290 AtomicReference<U> result) { 5291 super(p, b, i, f, t); 5292 this.searchFunction = searchFunction; this.result = result; 5293 } 5294 public final U getRawResult() { return result.get(); } 5295 public final void compute() { 5296 final Function<? super V, ? extends U> searchFunction; 5297 final AtomicReference<U> result; 5298 if ((searchFunction = this.searchFunction) != null && 5299 (result = this.result) != null) { 5300 for (int i = baseIndex, f, h; batch > 0 && 5301 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5302 if (result.get() != null) 5303 return; 5304 addToPendingCount(1); 5305 new SearchValuesTask<K,V,U> 5306 (this, batch >>>= 1, baseLimit = h, f, tab, 5307 searchFunction, result).fork(); 5308 } 5309 while (result.get() == null) { 5310 U u; 5311 Node<K,V> p; 5312 if ((p = advance()) == null) { 5313 propagateCompletion(); 5314 break; 5315 } 5316 if ((u = searchFunction.apply(p.val)) != null) { 5317 if (result.compareAndSet(null, u)) 5318 quietlyCompleteRoot(); 5319 break; 5320 } 5321 } 5322 } 5323 } 5324 } 5325 5326 @SuppressWarnings("serial") 5327 static final class SearchEntriesTask<K,V,U> 5328 extends BulkTask<K,V,U> { 5329 final Function<Entry<K,V>, ? extends U> searchFunction; 5330 final AtomicReference<U> result; 5331 SearchEntriesTask 5332 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5333 Function<Entry<K,V>, ? extends U> searchFunction, 5334 AtomicReference<U> result) { 5335 super(p, b, i, f, t); 5336 this.searchFunction = searchFunction; this.result = result; 5337 } 5338 public final U getRawResult() { return result.get(); } 5339 public final void compute() { 5340 final Function<Entry<K,V>, ? extends U> searchFunction; 5341 final AtomicReference<U> result; 5342 if ((searchFunction = this.searchFunction) != null && 5343 (result = this.result) != null) { 5344 for (int i = baseIndex, f, h; batch > 0 && 5345 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5346 if (result.get() != null) 5347 return; 5348 addToPendingCount(1); 5349 new SearchEntriesTask<K,V,U> 5350 (this, batch >>>= 1, baseLimit = h, f, tab, 5351 searchFunction, result).fork(); 5352 } 5353 while (result.get() == null) { 5354 U u; 5355 Node<K,V> p; 5356 if ((p = advance()) == null) { 5357 propagateCompletion(); 5358 break; 5359 } 5360 if ((u = searchFunction.apply(p)) != null) { 5361 if (result.compareAndSet(null, u)) 5362 quietlyCompleteRoot(); 5363 return; 5364 } 5365 } 5366 } 5367 } 5368 } 5369 5370 @SuppressWarnings("serial") 5371 static final class SearchMappingsTask<K,V,U> 5372 extends BulkTask<K,V,U> { 5373 final BiFunction<? super K, ? super V, ? extends U> searchFunction; 5374 final AtomicReference<U> result; 5375 SearchMappingsTask 5376 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5377 BiFunction<? super K, ? super V, ? extends U> searchFunction, 5378 AtomicReference<U> result) { 5379 super(p, b, i, f, t); 5380 this.searchFunction = searchFunction; this.result = result; 5381 } 5382 public final U getRawResult() { return result.get(); } 5383 public final void compute() { 5384 final BiFunction<? super K, ? super V, ? extends U> searchFunction; 5385 final AtomicReference<U> result; 5386 if ((searchFunction = this.searchFunction) != null && 5387 (result = this.result) != null) { 5388 for (int i = baseIndex, f, h; batch > 0 && 5389 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5390 if (result.get() != null) 5391 return; 5392 addToPendingCount(1); 5393 new SearchMappingsTask<K,V,U> 5394 (this, batch >>>= 1, baseLimit = h, f, tab, 5395 searchFunction, result).fork(); 5396 } 5397 while (result.get() == null) { 5398 U u; 5399 Node<K,V> p; 5400 if ((p = advance()) == null) { 5401 propagateCompletion(); 5402 break; 5403 } 5404 if ((u = searchFunction.apply(p.key, p.val)) != null) { 5405 if (result.compareAndSet(null, u)) 5406 quietlyCompleteRoot(); 5407 break; 5408 } 5409 } 5410 } 5411 } 5412 } 5413 5414 @SuppressWarnings("serial") 5415 static final class ReduceKeysTask<K,V> 5416 extends BulkTask<K,V,K> { 5417 final BiFunction<? super K, ? super K, ? extends K> reducer; 5418 K result; 5419 ReduceKeysTask<K,V> rights, nextRight; 5420 ReduceKeysTask 5421 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5422 ReduceKeysTask<K,V> nextRight, 5423 BiFunction<? super K, ? super K, ? extends K> reducer) { 5424 super(p, b, i, f, t); this.nextRight = nextRight; 5425 this.reducer = reducer; 5426 } 5427 public final K getRawResult() { return result; } 5428 public final void compute() { 5429 final BiFunction<? super K, ? super K, ? extends K> reducer; 5430 if ((reducer = this.reducer) != null) { 5431 for (int i = baseIndex, f, h; batch > 0 && 5432 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5433 addToPendingCount(1); 5434 (rights = new ReduceKeysTask<K,V> 5435 (this, batch >>>= 1, baseLimit = h, f, tab, 5436 rights, reducer)).fork(); 5437 } 5438 K r = null; 5439 for (Node<K,V> p; (p = advance()) != null; ) { 5440 K u = p.key; 5441 r = (r == null) ? u : u == null ? r : reducer.apply(r, u); 5442 } 5443 result = r; 5444 CountedCompleter<?> c; 5445 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5446 @SuppressWarnings("unchecked") 5447 ReduceKeysTask<K,V> 5448 t = (ReduceKeysTask<K,V>)c, 5449 s = t.rights; 5450 while (s != null) { 5451 K tr, sr; 5452 if ((sr = s.result) != null) 5453 t.result = (((tr = t.result) == null) ? sr : 5454 reducer.apply(tr, sr)); 5455 s = t.rights = s.nextRight; 5456 } 5457 } 5458 } 5459 } 5460 } 5461 5462 @SuppressWarnings("serial") 5463 static final class ReduceValuesTask<K,V> 5464 extends BulkTask<K,V,V> { 5465 final BiFunction<? super V, ? super V, ? extends V> reducer; 5466 V result; 5467 ReduceValuesTask<K,V> rights, nextRight; 5468 ReduceValuesTask 5469 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5470 ReduceValuesTask<K,V> nextRight, 5471 BiFunction<? super V, ? super V, ? extends V> reducer) { 5472 super(p, b, i, f, t); this.nextRight = nextRight; 5473 this.reducer = reducer; 5474 } 5475 public final V getRawResult() { return result; } 5476 public final void compute() { 5477 final BiFunction<? super V, ? super V, ? extends V> reducer; 5478 if ((reducer = this.reducer) != null) { 5479 for (int i = baseIndex, f, h; batch > 0 && 5480 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5481 addToPendingCount(1); 5482 (rights = new ReduceValuesTask<K,V> 5483 (this, batch >>>= 1, baseLimit = h, f, tab, 5484 rights, reducer)).fork(); 5485 } 5486 V r = null; 5487 for (Node<K,V> p; (p = advance()) != null; ) { 5488 V v = p.val; 5489 r = (r == null) ? v : reducer.apply(r, v); 5490 } 5491 result = r; 5492 CountedCompleter<?> c; 5493 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5494 @SuppressWarnings("unchecked") 5495 ReduceValuesTask<K,V> 5496 t = (ReduceValuesTask<K,V>)c, 5497 s = t.rights; 5498 while (s != null) { 5499 V tr, sr; 5500 if ((sr = s.result) != null) 5501 t.result = (((tr = t.result) == null) ? sr : 5502 reducer.apply(tr, sr)); 5503 s = t.rights = s.nextRight; 5504 } 5505 } 5506 } 5507 } 5508 } 5509 5510 @SuppressWarnings("serial") 5511 static final class ReduceEntriesTask<K,V> 5512 extends BulkTask<K,V,Map.Entry<K,V>> { 5513 final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; 5514 Map.Entry<K,V> result; 5515 ReduceEntriesTask<K,V> rights, nextRight; 5516 ReduceEntriesTask 5517 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5518 ReduceEntriesTask<K,V> nextRight, 5519 BiFunction<Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer) { 5520 super(p, b, i, f, t); this.nextRight = nextRight; 5521 this.reducer = reducer; 5522 } 5523 public final Map.Entry<K,V> getRawResult() { return result; } 5524 public final void compute() { 5525 final BiFunction<Map.Entry<K,V>, Map.Entry<K,V>, ? extends Map.Entry<K,V>> reducer; 5526 if ((reducer = this.reducer) != null) { 5527 for (int i = baseIndex, f, h; batch > 0 && 5528 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5529 addToPendingCount(1); 5530 (rights = new ReduceEntriesTask<K,V> 5531 (this, batch >>>= 1, baseLimit = h, f, tab, 5532 rights, reducer)).fork(); 5533 } 5534 Map.Entry<K,V> r = null; 5535 for (Node<K,V> p; (p = advance()) != null; ) 5536 r = (r == null) ? p : reducer.apply(r, p); 5537 result = r; 5538 CountedCompleter<?> c; 5539 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5540 @SuppressWarnings("unchecked") 5541 ReduceEntriesTask<K,V> 5542 t = (ReduceEntriesTask<K,V>)c, 5543 s = t.rights; 5544 while (s != null) { 5545 Map.Entry<K,V> tr, sr; 5546 if ((sr = s.result) != null) 5547 t.result = (((tr = t.result) == null) ? sr : 5548 reducer.apply(tr, sr)); 5549 s = t.rights = s.nextRight; 5550 } 5551 } 5552 } 5553 } 5554 } 5555 5556 @SuppressWarnings("serial") 5557 static final class MapReduceKeysTask<K,V,U> 5558 extends BulkTask<K,V,U> { 5559 final Function<? super K, ? extends U> transformer; 5560 final BiFunction<? super U, ? super U, ? extends U> reducer; 5561 U result; 5562 MapReduceKeysTask<K,V,U> rights, nextRight; 5563 MapReduceKeysTask 5564 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5565 MapReduceKeysTask<K,V,U> nextRight, 5566 Function<? super K, ? extends U> transformer, 5567 BiFunction<? super U, ? super U, ? extends U> reducer) { 5568 super(p, b, i, f, t); this.nextRight = nextRight; 5569 this.transformer = transformer; 5570 this.reducer = reducer; 5571 } 5572 public final U getRawResult() { return result; } 5573 public final void compute() { 5574 final Function<? super K, ? extends U> transformer; 5575 final BiFunction<? super U, ? super U, ? extends U> reducer; 5576 if ((transformer = this.transformer) != null && 5577 (reducer = this.reducer) != null) { 5578 for (int i = baseIndex, f, h; batch > 0 && 5579 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5580 addToPendingCount(1); 5581 (rights = new MapReduceKeysTask<K,V,U> 5582 (this, batch >>>= 1, baseLimit = h, f, tab, 5583 rights, transformer, reducer)).fork(); 5584 } 5585 U r = null; 5586 for (Node<K,V> p; (p = advance()) != null; ) { 5587 U u; 5588 if ((u = transformer.apply(p.key)) != null) 5589 r = (r == null) ? u : reducer.apply(r, u); 5590 } 5591 result = r; 5592 CountedCompleter<?> c; 5593 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5594 @SuppressWarnings("unchecked") 5595 MapReduceKeysTask<K,V,U> 5596 t = (MapReduceKeysTask<K,V,U>)c, 5597 s = t.rights; 5598 while (s != null) { 5599 U tr, sr; 5600 if ((sr = s.result) != null) 5601 t.result = (((tr = t.result) == null) ? sr : 5602 reducer.apply(tr, sr)); 5603 s = t.rights = s.nextRight; 5604 } 5605 } 5606 } 5607 } 5608 } 5609 5610 @SuppressWarnings("serial") 5611 static final class MapReduceValuesTask<K,V,U> 5612 extends BulkTask<K,V,U> { 5613 final Function<? super V, ? extends U> transformer; 5614 final BiFunction<? super U, ? super U, ? extends U> reducer; 5615 U result; 5616 MapReduceValuesTask<K,V,U> rights, nextRight; 5617 MapReduceValuesTask 5618 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5619 MapReduceValuesTask<K,V,U> nextRight, 5620 Function<? super V, ? extends U> transformer, 5621 BiFunction<? super U, ? super U, ? extends U> reducer) { 5622 super(p, b, i, f, t); this.nextRight = nextRight; 5623 this.transformer = transformer; 5624 this.reducer = reducer; 5625 } 5626 public final U getRawResult() { return result; } 5627 public final void compute() { 5628 final Function<? super V, ? extends U> transformer; 5629 final BiFunction<? super U, ? super U, ? extends U> reducer; 5630 if ((transformer = this.transformer) != null && 5631 (reducer = this.reducer) != null) { 5632 for (int i = baseIndex, f, h; batch > 0 && 5633 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5634 addToPendingCount(1); 5635 (rights = new MapReduceValuesTask<K,V,U> 5636 (this, batch >>>= 1, baseLimit = h, f, tab, 5637 rights, transformer, reducer)).fork(); 5638 } 5639 U r = null; 5640 for (Node<K,V> p; (p = advance()) != null; ) { 5641 U u; 5642 if ((u = transformer.apply(p.val)) != null) 5643 r = (r == null) ? u : reducer.apply(r, u); 5644 } 5645 result = r; 5646 CountedCompleter<?> c; 5647 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5648 @SuppressWarnings("unchecked") 5649 MapReduceValuesTask<K,V,U> 5650 t = (MapReduceValuesTask<K,V,U>)c, 5651 s = t.rights; 5652 while (s != null) { 5653 U tr, sr; 5654 if ((sr = s.result) != null) 5655 t.result = (((tr = t.result) == null) ? sr : 5656 reducer.apply(tr, sr)); 5657 s = t.rights = s.nextRight; 5658 } 5659 } 5660 } 5661 } 5662 } 5663 5664 @SuppressWarnings("serial") 5665 static final class MapReduceEntriesTask<K,V,U> 5666 extends BulkTask<K,V,U> { 5667 final Function<Map.Entry<K,V>, ? extends U> transformer; 5668 final BiFunction<? super U, ? super U, ? extends U> reducer; 5669 U result; 5670 MapReduceEntriesTask<K,V,U> rights, nextRight; 5671 MapReduceEntriesTask 5672 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5673 MapReduceEntriesTask<K,V,U> nextRight, 5674 Function<Map.Entry<K,V>, ? extends U> transformer, 5675 BiFunction<? super U, ? super U, ? extends U> reducer) { 5676 super(p, b, i, f, t); this.nextRight = nextRight; 5677 this.transformer = transformer; 5678 this.reducer = reducer; 5679 } 5680 public final U getRawResult() { return result; } 5681 public final void compute() { 5682 final Function<Map.Entry<K,V>, ? extends U> transformer; 5683 final BiFunction<? super U, ? super U, ? extends U> reducer; 5684 if ((transformer = this.transformer) != null && 5685 (reducer = this.reducer) != null) { 5686 for (int i = baseIndex, f, h; batch > 0 && 5687 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5688 addToPendingCount(1); 5689 (rights = new MapReduceEntriesTask<K,V,U> 5690 (this, batch >>>= 1, baseLimit = h, f, tab, 5691 rights, transformer, reducer)).fork(); 5692 } 5693 U r = null; 5694 for (Node<K,V> p; (p = advance()) != null; ) { 5695 U u; 5696 if ((u = transformer.apply(p)) != null) 5697 r = (r == null) ? u : reducer.apply(r, u); 5698 } 5699 result = r; 5700 CountedCompleter<?> c; 5701 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5702 @SuppressWarnings("unchecked") 5703 MapReduceEntriesTask<K,V,U> 5704 t = (MapReduceEntriesTask<K,V,U>)c, 5705 s = t.rights; 5706 while (s != null) { 5707 U tr, sr; 5708 if ((sr = s.result) != null) 5709 t.result = (((tr = t.result) == null) ? sr : 5710 reducer.apply(tr, sr)); 5711 s = t.rights = s.nextRight; 5712 } 5713 } 5714 } 5715 } 5716 } 5717 5718 @SuppressWarnings("serial") 5719 static final class MapReduceMappingsTask<K,V,U> 5720 extends BulkTask<K,V,U> { 5721 final BiFunction<? super K, ? super V, ? extends U> transformer; 5722 final BiFunction<? super U, ? super U, ? extends U> reducer; 5723 U result; 5724 MapReduceMappingsTask<K,V,U> rights, nextRight; 5725 MapReduceMappingsTask 5726 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5727 MapReduceMappingsTask<K,V,U> nextRight, 5728 BiFunction<? super K, ? super V, ? extends U> transformer, 5729 BiFunction<? super U, ? super U, ? extends U> reducer) { 5730 super(p, b, i, f, t); this.nextRight = nextRight; 5731 this.transformer = transformer; 5732 this.reducer = reducer; 5733 } 5734 public final U getRawResult() { return result; } 5735 public final void compute() { 5736 final BiFunction<? super K, ? super V, ? extends U> transformer; 5737 final BiFunction<? super U, ? super U, ? extends U> reducer; 5738 if ((transformer = this.transformer) != null && 5739 (reducer = this.reducer) != null) { 5740 for (int i = baseIndex, f, h; batch > 0 && 5741 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5742 addToPendingCount(1); 5743 (rights = new MapReduceMappingsTask<K,V,U> 5744 (this, batch >>>= 1, baseLimit = h, f, tab, 5745 rights, transformer, reducer)).fork(); 5746 } 5747 U r = null; 5748 for (Node<K,V> p; (p = advance()) != null; ) { 5749 U u; 5750 if ((u = transformer.apply(p.key, p.val)) != null) 5751 r = (r == null) ? u : reducer.apply(r, u); 5752 } 5753 result = r; 5754 CountedCompleter<?> c; 5755 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5756 @SuppressWarnings("unchecked") 5757 MapReduceMappingsTask<K,V,U> 5758 t = (MapReduceMappingsTask<K,V,U>)c, 5759 s = t.rights; 5760 while (s != null) { 5761 U tr, sr; 5762 if ((sr = s.result) != null) 5763 t.result = (((tr = t.result) == null) ? sr : 5764 reducer.apply(tr, sr)); 5765 s = t.rights = s.nextRight; 5766 } 5767 } 5768 } 5769 } 5770 } 5771 5772 @SuppressWarnings("serial") 5773 static final class MapReduceKeysToDoubleTask<K,V> 5774 extends BulkTask<K,V,Double> { 5775 final ToDoubleFunction<? super K> transformer; 5776 final DoubleBinaryOperator reducer; 5777 final double basis; 5778 double result; 5779 MapReduceKeysToDoubleTask<K,V> rights, nextRight; 5780 MapReduceKeysToDoubleTask 5781 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5782 MapReduceKeysToDoubleTask<K,V> nextRight, 5783 ToDoubleFunction<? super K> transformer, 5784 double basis, 5785 DoubleBinaryOperator reducer) { 5786 super(p, b, i, f, t); this.nextRight = nextRight; 5787 this.transformer = transformer; 5788 this.basis = basis; this.reducer = reducer; 5789 } 5790 public final Double getRawResult() { return result; } 5791 public final void compute() { 5792 final ToDoubleFunction<? super K> transformer; 5793 final DoubleBinaryOperator reducer; 5794 if ((transformer = this.transformer) != null && 5795 (reducer = this.reducer) != null) { 5796 double r = this.basis; 5797 for (int i = baseIndex, f, h; batch > 0 && 5798 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5799 addToPendingCount(1); 5800 (rights = new MapReduceKeysToDoubleTask<K,V> 5801 (this, batch >>>= 1, baseLimit = h, f, tab, 5802 rights, transformer, r, reducer)).fork(); 5803 } 5804 for (Node<K,V> p; (p = advance()) != null; ) 5805 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key)); 5806 result = r; 5807 CountedCompleter<?> c; 5808 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5809 @SuppressWarnings("unchecked") 5810 MapReduceKeysToDoubleTask<K,V> 5811 t = (MapReduceKeysToDoubleTask<K,V>)c, 5812 s = t.rights; 5813 while (s != null) { 5814 t.result = reducer.applyAsDouble(t.result, s.result); 5815 s = t.rights = s.nextRight; 5816 } 5817 } 5818 } 5819 } 5820 } 5821 5822 @SuppressWarnings("serial") 5823 static final class MapReduceValuesToDoubleTask<K,V> 5824 extends BulkTask<K,V,Double> { 5825 final ToDoubleFunction<? super V> transformer; 5826 final DoubleBinaryOperator reducer; 5827 final double basis; 5828 double result; 5829 MapReduceValuesToDoubleTask<K,V> rights, nextRight; 5830 MapReduceValuesToDoubleTask 5831 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5832 MapReduceValuesToDoubleTask<K,V> nextRight, 5833 ToDoubleFunction<? super V> transformer, 5834 double basis, 5835 DoubleBinaryOperator reducer) { 5836 super(p, b, i, f, t); this.nextRight = nextRight; 5837 this.transformer = transformer; 5838 this.basis = basis; this.reducer = reducer; 5839 } 5840 public final Double getRawResult() { return result; } 5841 public final void compute() { 5842 final ToDoubleFunction<? super V> transformer; 5843 final DoubleBinaryOperator reducer; 5844 if ((transformer = this.transformer) != null && 5845 (reducer = this.reducer) != null) { 5846 double r = this.basis; 5847 for (int i = baseIndex, f, h; batch > 0 && 5848 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5849 addToPendingCount(1); 5850 (rights = new MapReduceValuesToDoubleTask<K,V> 5851 (this, batch >>>= 1, baseLimit = h, f, tab, 5852 rights, transformer, r, reducer)).fork(); 5853 } 5854 for (Node<K,V> p; (p = advance()) != null; ) 5855 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.val)); 5856 result = r; 5857 CountedCompleter<?> c; 5858 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5859 @SuppressWarnings("unchecked") 5860 MapReduceValuesToDoubleTask<K,V> 5861 t = (MapReduceValuesToDoubleTask<K,V>)c, 5862 s = t.rights; 5863 while (s != null) { 5864 t.result = reducer.applyAsDouble(t.result, s.result); 5865 s = t.rights = s.nextRight; 5866 } 5867 } 5868 } 5869 } 5870 } 5871 5872 @SuppressWarnings("serial") 5873 static final class MapReduceEntriesToDoubleTask<K,V> 5874 extends BulkTask<K,V,Double> { 5875 final ToDoubleFunction<Map.Entry<K,V>> transformer; 5876 final DoubleBinaryOperator reducer; 5877 final double basis; 5878 double result; 5879 MapReduceEntriesToDoubleTask<K,V> rights, nextRight; 5880 MapReduceEntriesToDoubleTask 5881 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5882 MapReduceEntriesToDoubleTask<K,V> nextRight, 5883 ToDoubleFunction<Map.Entry<K,V>> transformer, 5884 double basis, 5885 DoubleBinaryOperator reducer) { 5886 super(p, b, i, f, t); this.nextRight = nextRight; 5887 this.transformer = transformer; 5888 this.basis = basis; this.reducer = reducer; 5889 } 5890 public final Double getRawResult() { return result; } 5891 public final void compute() { 5892 final ToDoubleFunction<Map.Entry<K,V>> transformer; 5893 final DoubleBinaryOperator reducer; 5894 if ((transformer = this.transformer) != null && 5895 (reducer = this.reducer) != null) { 5896 double r = this.basis; 5897 for (int i = baseIndex, f, h; batch > 0 && 5898 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5899 addToPendingCount(1); 5900 (rights = new MapReduceEntriesToDoubleTask<K,V> 5901 (this, batch >>>= 1, baseLimit = h, f, tab, 5902 rights, transformer, r, reducer)).fork(); 5903 } 5904 for (Node<K,V> p; (p = advance()) != null; ) 5905 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p)); 5906 result = r; 5907 CountedCompleter<?> c; 5908 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5909 @SuppressWarnings("unchecked") 5910 MapReduceEntriesToDoubleTask<K,V> 5911 t = (MapReduceEntriesToDoubleTask<K,V>)c, 5912 s = t.rights; 5913 while (s != null) { 5914 t.result = reducer.applyAsDouble(t.result, s.result); 5915 s = t.rights = s.nextRight; 5916 } 5917 } 5918 } 5919 } 5920 } 5921 5922 @SuppressWarnings("serial") 5923 static final class MapReduceMappingsToDoubleTask<K,V> 5924 extends BulkTask<K,V,Double> { 5925 final ToDoubleBiFunction<? super K, ? super V> transformer; 5926 final DoubleBinaryOperator reducer; 5927 final double basis; 5928 double result; 5929 MapReduceMappingsToDoubleTask<K,V> rights, nextRight; 5930 MapReduceMappingsToDoubleTask 5931 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5932 MapReduceMappingsToDoubleTask<K,V> nextRight, 5933 ToDoubleBiFunction<? super K, ? super V> transformer, 5934 double basis, 5935 DoubleBinaryOperator reducer) { 5936 super(p, b, i, f, t); this.nextRight = nextRight; 5937 this.transformer = transformer; 5938 this.basis = basis; this.reducer = reducer; 5939 } 5940 public final Double getRawResult() { return result; } 5941 public final void compute() { 5942 final ToDoubleBiFunction<? super K, ? super V> transformer; 5943 final DoubleBinaryOperator reducer; 5944 if ((transformer = this.transformer) != null && 5945 (reducer = this.reducer) != null) { 5946 double r = this.basis; 5947 for (int i = baseIndex, f, h; batch > 0 && 5948 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5949 addToPendingCount(1); 5950 (rights = new MapReduceMappingsToDoubleTask<K,V> 5951 (this, batch >>>= 1, baseLimit = h, f, tab, 5952 rights, transformer, r, reducer)).fork(); 5953 } 5954 for (Node<K,V> p; (p = advance()) != null; ) 5955 r = reducer.applyAsDouble(r, transformer.applyAsDouble(p.key, p.val)); 5956 result = r; 5957 CountedCompleter<?> c; 5958 for (c = firstComplete(); c != null; c = c.nextComplete()) { 5959 @SuppressWarnings("unchecked") 5960 MapReduceMappingsToDoubleTask<K,V> 5961 t = (MapReduceMappingsToDoubleTask<K,V>)c, 5962 s = t.rights; 5963 while (s != null) { 5964 t.result = reducer.applyAsDouble(t.result, s.result); 5965 s = t.rights = s.nextRight; 5966 } 5967 } 5968 } 5969 } 5970 } 5971 5972 @SuppressWarnings("serial") 5973 static final class MapReduceKeysToLongTask<K,V> 5974 extends BulkTask<K,V,Long> { 5975 final ToLongFunction<? super K> transformer; 5976 final LongBinaryOperator reducer; 5977 final long basis; 5978 long result; 5979 MapReduceKeysToLongTask<K,V> rights, nextRight; 5980 MapReduceKeysToLongTask 5981 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 5982 MapReduceKeysToLongTask<K,V> nextRight, 5983 ToLongFunction<? super K> transformer, 5984 long basis, 5985 LongBinaryOperator reducer) { 5986 super(p, b, i, f, t); this.nextRight = nextRight; 5987 this.transformer = transformer; 5988 this.basis = basis; this.reducer = reducer; 5989 } 5990 public final Long getRawResult() { return result; } 5991 public final void compute() { 5992 final ToLongFunction<? super K> transformer; 5993 final LongBinaryOperator reducer; 5994 if ((transformer = this.transformer) != null && 5995 (reducer = this.reducer) != null) { 5996 long r = this.basis; 5997 for (int i = baseIndex, f, h; batch > 0 && 5998 (h = ((f = baseLimit) + i) >>> 1) > i;) { 5999 addToPendingCount(1); 6000 (rights = new MapReduceKeysToLongTask<K,V> 6001 (this, batch >>>= 1, baseLimit = h, f, tab, 6002 rights, transformer, r, reducer)).fork(); 6003 } 6004 for (Node<K,V> p; (p = advance()) != null; ) 6005 r = reducer.applyAsLong(r, transformer.applyAsLong(p.key)); 6006 result = r; 6007 CountedCompleter<?> c; 6008 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6009 @SuppressWarnings("unchecked") 6010 MapReduceKeysToLongTask<K,V> 6011 t = (MapReduceKeysToLongTask<K,V>)c, 6012 s = t.rights; 6013 while (s != null) { 6014 t.result = reducer.applyAsLong(t.result, s.result); 6015 s = t.rights = s.nextRight; 6016 } 6017 } 6018 } 6019 } 6020 } 6021 6022 @SuppressWarnings("serial") 6023 static final class MapReduceValuesToLongTask<K,V> 6024 extends BulkTask<K,V,Long> { 6025 final ToLongFunction<? super V> transformer; 6026 final LongBinaryOperator reducer; 6027 final long basis; 6028 long result; 6029 MapReduceValuesToLongTask<K,V> rights, nextRight; 6030 MapReduceValuesToLongTask 6031 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6032 MapReduceValuesToLongTask<K,V> nextRight, 6033 ToLongFunction<? super V> transformer, 6034 long basis, 6035 LongBinaryOperator reducer) { 6036 super(p, b, i, f, t); this.nextRight = nextRight; 6037 this.transformer = transformer; 6038 this.basis = basis; this.reducer = reducer; 6039 } 6040 public final Long getRawResult() { return result; } 6041 public final void compute() { 6042 final ToLongFunction<? super V> transformer; 6043 final LongBinaryOperator reducer; 6044 if ((transformer = this.transformer) != null && 6045 (reducer = this.reducer) != null) { 6046 long r = this.basis; 6047 for (int i = baseIndex, f, h; batch > 0 && 6048 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6049 addToPendingCount(1); 6050 (rights = new MapReduceValuesToLongTask<K,V> 6051 (this, batch >>>= 1, baseLimit = h, f, tab, 6052 rights, transformer, r, reducer)).fork(); 6053 } 6054 for (Node<K,V> p; (p = advance()) != null; ) 6055 r = reducer.applyAsLong(r, transformer.applyAsLong(p.val)); 6056 result = r; 6057 CountedCompleter<?> c; 6058 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6059 @SuppressWarnings("unchecked") 6060 MapReduceValuesToLongTask<K,V> 6061 t = (MapReduceValuesToLongTask<K,V>)c, 6062 s = t.rights; 6063 while (s != null) { 6064 t.result = reducer.applyAsLong(t.result, s.result); 6065 s = t.rights = s.nextRight; 6066 } 6067 } 6068 } 6069 } 6070 } 6071 6072 @SuppressWarnings("serial") 6073 static final class MapReduceEntriesToLongTask<K,V> 6074 extends BulkTask<K,V,Long> { 6075 final ToLongFunction<Map.Entry<K,V>> transformer; 6076 final LongBinaryOperator reducer; 6077 final long basis; 6078 long result; 6079 MapReduceEntriesToLongTask<K,V> rights, nextRight; 6080 MapReduceEntriesToLongTask 6081 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6082 MapReduceEntriesToLongTask<K,V> nextRight, 6083 ToLongFunction<Map.Entry<K,V>> transformer, 6084 long basis, 6085 LongBinaryOperator reducer) { 6086 super(p, b, i, f, t); this.nextRight = nextRight; 6087 this.transformer = transformer; 6088 this.basis = basis; this.reducer = reducer; 6089 } 6090 public final Long getRawResult() { return result; } 6091 public final void compute() { 6092 final ToLongFunction<Map.Entry<K,V>> transformer; 6093 final LongBinaryOperator reducer; 6094 if ((transformer = this.transformer) != null && 6095 (reducer = this.reducer) != null) { 6096 long r = this.basis; 6097 for (int i = baseIndex, f, h; batch > 0 && 6098 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6099 addToPendingCount(1); 6100 (rights = new MapReduceEntriesToLongTask<K,V> 6101 (this, batch >>>= 1, baseLimit = h, f, tab, 6102 rights, transformer, r, reducer)).fork(); 6103 } 6104 for (Node<K,V> p; (p = advance()) != null; ) 6105 r = reducer.applyAsLong(r, transformer.applyAsLong(p)); 6106 result = r; 6107 CountedCompleter<?> c; 6108 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6109 @SuppressWarnings("unchecked") 6110 MapReduceEntriesToLongTask<K,V> 6111 t = (MapReduceEntriesToLongTask<K,V>)c, 6112 s = t.rights; 6113 while (s != null) { 6114 t.result = reducer.applyAsLong(t.result, s.result); 6115 s = t.rights = s.nextRight; 6116 } 6117 } 6118 } 6119 } 6120 } 6121 6122 @SuppressWarnings("serial") 6123 static final class MapReduceMappingsToLongTask<K,V> 6124 extends BulkTask<K,V,Long> { 6125 final ToLongBiFunction<? super K, ? super V> transformer; 6126 final LongBinaryOperator reducer; 6127 final long basis; 6128 long result; 6129 MapReduceMappingsToLongTask<K,V> rights, nextRight; 6130 MapReduceMappingsToLongTask 6131 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6132 MapReduceMappingsToLongTask<K,V> nextRight, 6133 ToLongBiFunction<? super K, ? super V> transformer, 6134 long basis, 6135 LongBinaryOperator reducer) { 6136 super(p, b, i, f, t); this.nextRight = nextRight; 6137 this.transformer = transformer; 6138 this.basis = basis; this.reducer = reducer; 6139 } 6140 public final Long getRawResult() { return result; } 6141 public final void compute() { 6142 final ToLongBiFunction<? super K, ? super V> transformer; 6143 final LongBinaryOperator reducer; 6144 if ((transformer = this.transformer) != null && 6145 (reducer = this.reducer) != null) { 6146 long r = this.basis; 6147 for (int i = baseIndex, f, h; batch > 0 && 6148 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6149 addToPendingCount(1); 6150 (rights = new MapReduceMappingsToLongTask<K,V> 6151 (this, batch >>>= 1, baseLimit = h, f, tab, 6152 rights, transformer, r, reducer)).fork(); 6153 } 6154 for (Node<K,V> p; (p = advance()) != null; ) 6155 r = reducer.applyAsLong(r, transformer.applyAsLong(p.key, p.val)); 6156 result = r; 6157 CountedCompleter<?> c; 6158 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6159 @SuppressWarnings("unchecked") 6160 MapReduceMappingsToLongTask<K,V> 6161 t = (MapReduceMappingsToLongTask<K,V>)c, 6162 s = t.rights; 6163 while (s != null) { 6164 t.result = reducer.applyAsLong(t.result, s.result); 6165 s = t.rights = s.nextRight; 6166 } 6167 } 6168 } 6169 } 6170 } 6171 6172 @SuppressWarnings("serial") 6173 static final class MapReduceKeysToIntTask<K,V> 6174 extends BulkTask<K,V,Integer> { 6175 final ToIntFunction<? super K> transformer; 6176 final IntBinaryOperator reducer; 6177 final int basis; 6178 int result; 6179 MapReduceKeysToIntTask<K,V> rights, nextRight; 6180 MapReduceKeysToIntTask 6181 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6182 MapReduceKeysToIntTask<K,V> nextRight, 6183 ToIntFunction<? super K> transformer, 6184 int basis, 6185 IntBinaryOperator reducer) { 6186 super(p, b, i, f, t); this.nextRight = nextRight; 6187 this.transformer = transformer; 6188 this.basis = basis; this.reducer = reducer; 6189 } 6190 public final Integer getRawResult() { return result; } 6191 public final void compute() { 6192 final ToIntFunction<? super K> transformer; 6193 final IntBinaryOperator reducer; 6194 if ((transformer = this.transformer) != null && 6195 (reducer = this.reducer) != null) { 6196 int r = this.basis; 6197 for (int i = baseIndex, f, h; batch > 0 && 6198 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6199 addToPendingCount(1); 6200 (rights = new MapReduceKeysToIntTask<K,V> 6201 (this, batch >>>= 1, baseLimit = h, f, tab, 6202 rights, transformer, r, reducer)).fork(); 6203 } 6204 for (Node<K,V> p; (p = advance()) != null; ) 6205 r = reducer.applyAsInt(r, transformer.applyAsInt(p.key)); 6206 result = r; 6207 CountedCompleter<?> c; 6208 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6209 @SuppressWarnings("unchecked") 6210 MapReduceKeysToIntTask<K,V> 6211 t = (MapReduceKeysToIntTask<K,V>)c, 6212 s = t.rights; 6213 while (s != null) { 6214 t.result = reducer.applyAsInt(t.result, s.result); 6215 s = t.rights = s.nextRight; 6216 } 6217 } 6218 } 6219 } 6220 } 6221 6222 @SuppressWarnings("serial") 6223 static final class MapReduceValuesToIntTask<K,V> 6224 extends BulkTask<K,V,Integer> { 6225 final ToIntFunction<? super V> transformer; 6226 final IntBinaryOperator reducer; 6227 final int basis; 6228 int result; 6229 MapReduceValuesToIntTask<K,V> rights, nextRight; 6230 MapReduceValuesToIntTask 6231 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6232 MapReduceValuesToIntTask<K,V> nextRight, 6233 ToIntFunction<? super V> transformer, 6234 int basis, 6235 IntBinaryOperator reducer) { 6236 super(p, b, i, f, t); this.nextRight = nextRight; 6237 this.transformer = transformer; 6238 this.basis = basis; this.reducer = reducer; 6239 } 6240 public final Integer getRawResult() { return result; } 6241 public final void compute() { 6242 final ToIntFunction<? super V> transformer; 6243 final IntBinaryOperator reducer; 6244 if ((transformer = this.transformer) != null && 6245 (reducer = this.reducer) != null) { 6246 int r = this.basis; 6247 for (int i = baseIndex, f, h; batch > 0 && 6248 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6249 addToPendingCount(1); 6250 (rights = new MapReduceValuesToIntTask<K,V> 6251 (this, batch >>>= 1, baseLimit = h, f, tab, 6252 rights, transformer, r, reducer)).fork(); 6253 } 6254 for (Node<K,V> p; (p = advance()) != null; ) 6255 r = reducer.applyAsInt(r, transformer.applyAsInt(p.val)); 6256 result = r; 6257 CountedCompleter<?> c; 6258 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6259 @SuppressWarnings("unchecked") 6260 MapReduceValuesToIntTask<K,V> 6261 t = (MapReduceValuesToIntTask<K,V>)c, 6262 s = t.rights; 6263 while (s != null) { 6264 t.result = reducer.applyAsInt(t.result, s.result); 6265 s = t.rights = s.nextRight; 6266 } 6267 } 6268 } 6269 } 6270 } 6271 6272 @SuppressWarnings("serial") 6273 static final class MapReduceEntriesToIntTask<K,V> 6274 extends BulkTask<K,V,Integer> { 6275 final ToIntFunction<Map.Entry<K,V>> transformer; 6276 final IntBinaryOperator reducer; 6277 final int basis; 6278 int result; 6279 MapReduceEntriesToIntTask<K,V> rights, nextRight; 6280 MapReduceEntriesToIntTask 6281 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6282 MapReduceEntriesToIntTask<K,V> nextRight, 6283 ToIntFunction<Map.Entry<K,V>> transformer, 6284 int basis, 6285 IntBinaryOperator reducer) { 6286 super(p, b, i, f, t); this.nextRight = nextRight; 6287 this.transformer = transformer; 6288 this.basis = basis; this.reducer = reducer; 6289 } 6290 public final Integer getRawResult() { return result; } 6291 public final void compute() { 6292 final ToIntFunction<Map.Entry<K,V>> transformer; 6293 final IntBinaryOperator reducer; 6294 if ((transformer = this.transformer) != null && 6295 (reducer = this.reducer) != null) { 6296 int r = this.basis; 6297 for (int i = baseIndex, f, h; batch > 0 && 6298 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6299 addToPendingCount(1); 6300 (rights = new MapReduceEntriesToIntTask<K,V> 6301 (this, batch >>>= 1, baseLimit = h, f, tab, 6302 rights, transformer, r, reducer)).fork(); 6303 } 6304 for (Node<K,V> p; (p = advance()) != null; ) 6305 r = reducer.applyAsInt(r, transformer.applyAsInt(p)); 6306 result = r; 6307 CountedCompleter<?> c; 6308 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6309 @SuppressWarnings("unchecked") 6310 MapReduceEntriesToIntTask<K,V> 6311 t = (MapReduceEntriesToIntTask<K,V>)c, 6312 s = t.rights; 6313 while (s != null) { 6314 t.result = reducer.applyAsInt(t.result, s.result); 6315 s = t.rights = s.nextRight; 6316 } 6317 } 6318 } 6319 } 6320 } 6321 6322 @SuppressWarnings("serial") 6323 static final class MapReduceMappingsToIntTask<K,V> 6324 extends BulkTask<K,V,Integer> { 6325 final ToIntBiFunction<? super K, ? super V> transformer; 6326 final IntBinaryOperator reducer; 6327 final int basis; 6328 int result; 6329 MapReduceMappingsToIntTask<K,V> rights, nextRight; 6330 MapReduceMappingsToIntTask 6331 (BulkTask<K,V,?> p, int b, int i, int f, Node<K,V>[] t, 6332 MapReduceMappingsToIntTask<K,V> nextRight, 6333 ToIntBiFunction<? super K, ? super V> transformer, 6334 int basis, 6335 IntBinaryOperator reducer) { 6336 super(p, b, i, f, t); this.nextRight = nextRight; 6337 this.transformer = transformer; 6338 this.basis = basis; this.reducer = reducer; 6339 } 6340 public final Integer getRawResult() { return result; } 6341 public final void compute() { 6342 final ToIntBiFunction<? super K, ? super V> transformer; 6343 final IntBinaryOperator reducer; 6344 if ((transformer = this.transformer) != null && 6345 (reducer = this.reducer) != null) { 6346 int r = this.basis; 6347 for (int i = baseIndex, f, h; batch > 0 && 6348 (h = ((f = baseLimit) + i) >>> 1) > i;) { 6349 addToPendingCount(1); 6350 (rights = new MapReduceMappingsToIntTask<K,V> 6351 (this, batch >>>= 1, baseLimit = h, f, tab, 6352 rights, transformer, r, reducer)).fork(); 6353 } 6354 for (Node<K,V> p; (p = advance()) != null; ) 6355 r = reducer.applyAsInt(r, transformer.applyAsInt(p.key, p.val)); 6356 result = r; 6357 CountedCompleter<?> c; 6358 for (c = firstComplete(); c != null; c = c.nextComplete()) { 6359 @SuppressWarnings("unchecked") 6360 MapReduceMappingsToIntTask<K,V> 6361 t = (MapReduceMappingsToIntTask<K,V>)c, 6362 s = t.rights; 6363 while (s != null) { 6364 t.result = reducer.applyAsInt(t.result, s.result); 6365 s = t.rights = s.nextRight; 6366 } 6367 } 6368 } 6369 } 6370 } 6371 6372 // Unsafe mechanics 6373 private static final Unsafe U = Unsafe.getUnsafe(); 6374 private static final long SIZECTL 6375 = U.objectFieldOffset(ConcurrentHashMap.class, "sizeCtl"); 6376 private static final long TRANSFERINDEX 6377 = U.objectFieldOffset(ConcurrentHashMap.class, "transferIndex"); 6378 private static final long BASECOUNT 6379 = U.objectFieldOffset(ConcurrentHashMap.class, "baseCount"); 6380 private static final long CELLSBUSY 6381 = U.objectFieldOffset(ConcurrentHashMap.class, "cellsBusy"); 6382 private static final long CELLVALUE 6383 = U.objectFieldOffset(CounterCell.class, "value"); 6384 private static final long ABASE = U.arrayBaseOffset(Node[].class); 6385 private static final int ASHIFT; 6386 6387 static { 6388 int scale = U.arrayIndexScale(Node[].class); 6389 if ((scale & (scale - 1)) != 0) 6390 throw new ExceptionInInitializerError("array index scale not a power of two"); 6391 ASHIFT = 31 - Integer.numberOfLeadingZeros(scale); 6392 6393 // Reduce the risk of rare disastrous classloading in first call to 6394 // LockSupport.park: https://bugs.openjdk.org/browse/JDK-8074773 6395 Class<?> ensureLoaded = LockSupport.class; 6396 6397 // Eager class load observed to help JIT during startup 6398 ensureLoaded = ReservationNode.class; 6399 } 6400 }