1 /*
2 * Copyright (c) 2021, 2026, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.reflect;
27
28 import jdk.internal.javac.PreviewFeature;
29 import jdk.internal.reflect.AccessFlagSet;
30
31 import java.lang.classfile.ClassFile;
32 import java.lang.classfile.ClassModel;
33 import java.lang.classfile.FieldModel;
34 import java.lang.classfile.MethodModel;
35 import java.lang.classfile.attribute.InnerClassInfo;
36 import java.lang.classfile.attribute.MethodParameterInfo;
37 import java.lang.classfile.attribute.ModuleAttribute;
38 import java.lang.classfile.attribute.ModuleExportInfo;
39 import java.lang.classfile.attribute.ModuleOpenInfo;
40 import java.lang.classfile.attribute.ModuleRequireInfo;
41 import java.lang.module.ModuleDescriptor;
42 import java.util.List;
43 import java.util.Map;
44 import java.util.Objects;
45 import java.util.Set;
46
47 import static java.lang.classfile.ClassFile.*;
48 import static java.lang.reflect.ClassFileFormatVersion.*;
49
50 /**
51 * Represents a JVM access or module-related flag on a runtime member,
52 * such as a {@linkplain Class class}, {@linkplain Field field}, or
53 * {@linkplain Executable method}.
54 *
55 * <P>JVM access and module-related flags are related to, but distinct
56 * from Java language {@linkplain Modifier modifiers}. Some modifiers
57 * and access flags have a one-to-one correspondence, such as {@code
58 * public}. In other cases, some language-level modifiers do
59 * <em>not</em> have an access flag, such as {@code sealed} (JVMS
60 * {@jvms 4.7.31}) and some access flags have no corresponding
61 * modifier, such as {@linkplain #SYNTHETIC synthetic}.
62 *
63 * <p>The values for the constants representing the access and module
64 * flags are taken from sections of <cite>The Java Virtual Machine
65 * Specification</cite> including {@jvms 4.1} (class access and
66 * property modifiers), {@jvms 4.5} (field access and property flags),
67 * {@jvms 4.6} (method access and property flags), {@jvms 4.7.6}
68 * (nested class access and property flags), {@jvms 4.7.24} (method
69 * parameters), and {@jvms 4.7.25} (module flags and requires,
70 * exports, and opens flags).
71 *
72 * <p>The {@linkplain #mask() mask} values for the different access
73 * flags are <em>not</em> distinct. Flags are defined for different
74 * kinds of JVM structures and the same bit position has different
75 * meanings in different contexts. For example, {@code 0x0000_0040}
76 * indicates a {@link #VOLATILE volatile} field but a {@linkplain
77 * #BRIDGE bridge method}; {@code 0x0000_0080} indicates a {@link
78 * #TRANSIENT transient} field but a {@linkplain #VARARGS variable
79 * arity (varargs)} method.
80 *
81 * @implSpec
82 * The access flag constants are ordered by non-decreasing mask
83 * value; that is the mask value of a constant is greater than or
84 * equal to the mask value of an immediate neighbor to its (syntactic)
85 * left. If new constants are added, this property will be
86 * maintained. That implies new constants will not necessarily be
87 * added at the end of the existing list.
88 *
89 * @apiNote
90 * The JVM class file format has a {@linkplain ClassFileFormatVersion new version} defined for each new
91 * {@linkplain Runtime.Version#feature() feature release}. A new class
92 * file version may define new access flags or retire old ones. {@code
93 * AccessFlag} is intended to model the set of access flags across
94 * class file format versions. The range of versions an access flag is
95 * recognized is not explicitly indicated in this API. See the current
96 * <cite>The Java Virtual Machine Specification</cite> for
97 * details. Unless otherwise indicated, access flags can be assumed to
98 * be recognized in the {@linkplain Runtime#version() current
99 * version}.
100 *
101 * @see java.lang.reflect.Modifier
102 * @see java.lang.module.ModuleDescriptor.Modifier
103 * @see java.lang.module.ModuleDescriptor.Requires.Modifier
104 * @see java.lang.module.ModuleDescriptor.Exports.Modifier
105 * @see java.lang.module.ModuleDescriptor.Opens.Modifier
106 * @see java.compiler/javax.lang.model.element.Modifier
107 * @since 20
108 */
109 @SuppressWarnings("doclint:reference") // cross-module link
110 public enum AccessFlag {
111 /**
112 * The access flag {@code ACC_PUBLIC}, corresponding to the source
113 * modifier {@link Modifier#PUBLIC public}, with a mask value of
114 * <code>{@value "0x%04x" Modifier#PUBLIC}</code>.
115 */
116 PUBLIC(Modifier.PUBLIC, true,
117 Location.SET_CLASS_FIELD_METHOD_INNER_CLASS,
118 List.of(Map.entry(RELEASE_0, Location.SET_CLASS_FIELD_METHOD))),
119
120 /**
121 * The access flag {@code ACC_PRIVATE}, corresponding to the
122 * source modifier {@link Modifier#PRIVATE private}, with a mask
123 * value of <code>{@value "0x%04x" Modifier#PRIVATE}</code>.
124 */
125 PRIVATE(Modifier.PRIVATE, true, Location.SET_FIELD_METHOD_INNER_CLASS,
126 List.of(Map.entry(RELEASE_0, Location.SET_FIELD_METHOD))),
127
128 /**
129 * The access flag {@code ACC_PROTECTED}, corresponding to the
130 * source modifier {@link Modifier#PROTECTED protected}, with a mask
131 * value of <code>{@value "0x%04x" Modifier#PROTECTED}</code>.
132 */
133 PROTECTED(Modifier.PROTECTED, true, Location.SET_FIELD_METHOD_INNER_CLASS,
134 List.of(Map.entry(RELEASE_0, Location.SET_FIELD_METHOD))),
135
136 /**
137 * The access flag {@code ACC_STATIC}, corresponding to the source
138 * modifier {@link Modifier#STATIC static}, with a mask value of
139 * <code>{@value "0x%04x" Modifier#STATIC}</code>.
140 */
141 STATIC(Modifier.STATIC, true, Location.SET_FIELD_METHOD_INNER_CLASS,
142 List.of(Map.entry(RELEASE_0, Location.SET_FIELD_METHOD))),
143
144 /**
145 * The access flag {@code ACC_FINAL}, corresponding to the source
146 * modifier {@link Modifier#FINAL final}, with a mask
147 * value of <code>{@value "0x%04x" Modifier#FINAL}</code>.
148 */
149 FINAL(Modifier.FINAL, true,
150 Location.SET_FINAL_8,
151 List.of(Map.entry(RELEASE_7, Location.SET_CLASS_FIELD_METHOD_INNER_CLASS),
152 Map.entry(RELEASE_0, Location.SET_CLASS_FIELD_METHOD))),
153
154 /**
155 * The access flag {@code ACC_SUPER} with a mask value of {@code
156 * 0x0020}.
157 *
158 * @apiNote
159 * In Java SE 8 and above, the JVM treats the {@code ACC_SUPER}
160 * flag as set in every class file (JVMS {@jvms 4.1}).
161 * If preview feature is enabled,
162 * the {@code 0x0020} access flag bit is {@linkplain #IDENTITY IDENTITY access flag}.
163 */
164 SUPER(0x0000_0020, false,
165 Location.SET_CLASS,
166 List.of()),
167
168 /**
169 * The access flag {@code ACC_IDENTITY} with a mask value of
170 * <code>{@value "0x%04x" ClassFile#ACC_IDENTITY}</code>.
171 *
172 * @jvms value-objects-4.1 Class access and property modifiers
173 * @since Valhalla
174 */
175 @PreviewFeature(feature = PreviewFeature.Feature.VALUE_OBJECTS, reflective=true)
176 IDENTITY(ACC_IDENTITY, false,
177 Location.EMPTY_SET,
178 List.of()),
179
180 /**
181 * The module flag {@code ACC_OPEN} with a mask value of {@code
182 * 0x0020}.
183 * @see java.lang.module.ModuleDescriptor#isOpen
184 */
185 OPEN(0x0000_0020, false, Location.SET_MODULE,
186 List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
187
188 /**
189 * The module requires flag {@code ACC_TRANSITIVE} with a mask
190 * value of {@code 0x0020}.
191 * @see java.lang.module.ModuleDescriptor.Requires.Modifier#TRANSITIVE
192 */
193 TRANSITIVE(0x0000_0020, false, Location.SET_MODULE_REQUIRES,
194 List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
195
196 /**
197 * The access flag {@code ACC_SYNCHRONIZED}, corresponding to the
198 * source modifier {@link Modifier#SYNCHRONIZED synchronized}, with
199 * a mask value of <code>{@value "0x%04x" Modifier#SYNCHRONIZED}</code>.
200 */
201 SYNCHRONIZED(Modifier.SYNCHRONIZED, true, Location.SET_METHOD, List.of()),
202
203 /**
204 * The module requires flag {@code ACC_STATIC_PHASE} with a mask
205 * value of {@code 0x0040}.
206 * @see java.lang.module.ModuleDescriptor.Requires.Modifier#STATIC
207 */
208 STATIC_PHASE(0x0000_0040, false, Location.SET_MODULE_REQUIRES,
209 List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
210
211 /**
212 * The access flag {@code ACC_VOLATILE}, corresponding to the
213 * source modifier {@link Modifier#VOLATILE volatile}, with a mask
214 * value of <code>{@value "0x%04x" Modifier#VOLATILE}</code>.
215 */
216 VOLATILE(Modifier.VOLATILE, true, Location.SET_FIELD, List.of()),
217
218 /**
219 * The access flag {@code ACC_BRIDGE} with a mask value of
220 * <code>{@value "0x%04x" Modifier#BRIDGE}</code>
221 * @see Method#isBridge()
222 */
223 BRIDGE(Modifier.BRIDGE, false, Location.SET_METHOD,
224 List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
225
226 /**
227 * The access flag {@code ACC_TRANSIENT}, corresponding to the
228 * source modifier {@link Modifier#TRANSIENT transient}, with a
229 * mask value of <code>{@value "0x%04x" Modifier#TRANSIENT}</code>.
230 */
231 TRANSIENT(Modifier.TRANSIENT, true, Location.SET_FIELD, List.of()),
232
233 /**
234 * The access flag {@code ACC_VARARGS} with a mask value of
235 * <code>{@value "0x%04x" Modifier#VARARGS}</code>.
236 * @see Executable#isVarArgs()
237 */
238 VARARGS(Modifier.VARARGS, false, Location.SET_METHOD,
239 List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
240
241 /**
242 * The access flag {@code ACC_NATIVE}, corresponding to the source
243 * modifier {@link Modifier#NATIVE native}, with a mask value of
244 * <code>{@value "0x%04x" Modifier#NATIVE}</code>.
245 */
246 NATIVE(Modifier.NATIVE, true, Location.SET_METHOD, List.of()),
247
248 /**
249 * The access flag {@code ACC_INTERFACE} with a mask value of
250 * {@code 0x0200}.
251 * @see Class#isInterface()
252 */
253 INTERFACE(Modifier.INTERFACE, false, Location.SET_CLASS_INNER_CLASS,
254 List.of(Map.entry(RELEASE_0, Location.SET_CLASS))),
255
256 /**
257 * The access flag {@code ACC_ABSTRACT}, corresponding to the
258 * source modifier {@link Modifier#ABSTRACT abstract}, with a mask
259 * value of <code>{@value "0x%04x" Modifier#ABSTRACT}</code>.
260 */
261 ABSTRACT(Modifier.ABSTRACT, true,
262 Location.SET_CLASS_METHOD_INNER_CLASS,
263 List.of(Map.entry(RELEASE_0, Location.SET_CLASS_METHOD))),
264
265 /**
266 * The access flag {@code ACC_STRICT}, corresponding to the source
267 * modifier {@link Modifier#STRICT strictfp}, with a mask value of
268 * <code>{@value "0x%04x" Modifier#STRICT}</code>.
269 *
270 * @apiNote
271 * The {@code ACC_STRICT} access flag is defined for class file
272 * major versions 46 through 60, inclusive (JVMS {@jvms 4.6}),
273 * corresponding to Java SE 1.2 through 16.
274 */
275 STRICT(Modifier.STRICT, true, Location.EMPTY_SET,
276 List.of(Map.entry(RELEASE_16, Location.SET_METHOD),
277 Map.entry(RELEASE_1, Location.EMPTY_SET))),
278
279 /**
280 * The access flag {@code ACC_STRICT_INIT}, with a mask value of
281 * <code>{@value "0x%04x" ClassFile#ACC_STRICT_INIT}</code>.
282 *
283 * @jvms strict-fields-4.5 Field access and property flags
284 * @since Valhalla
285 */
286 @PreviewFeature(feature = PreviewFeature.Feature.STRICT_FIELDS, reflective=true)
287 STRICT_INIT(ACC_STRICT_INIT, false,
288 Location.EMPTY_SET,
289 List.of()),
290
291 /**
292 * The access flag {@code ACC_SYNTHETIC} with a mask value of
293 * <code>{@value "0x%04x" Modifier#SYNTHETIC}</code>.
294 * @see Class#isSynthetic()
295 * @see Executable#isSynthetic()
296 * @see java.lang.module.ModuleDescriptor.Modifier#SYNTHETIC
297 */
298 SYNTHETIC(Modifier.SYNTHETIC, false, Location.SET_SYNTHETIC_9,
299 List.of(Map.entry(RELEASE_8, Location.SET_SYNTHETIC_8),
300 Map.entry(RELEASE_7, Location.SET_SYNTHETIC_5),
301 Map.entry(RELEASE_4, Location.EMPTY_SET))),
302
303 /**
304 * The access flag {@code ACC_ANNOTATION} with a mask value of
305 * <code>{@value "0x%04x" Modifier#ANNOTATION}</code>.
306 * @see Class#isAnnotation()
307 */
308 ANNOTATION(Modifier.ANNOTATION, false, Location.SET_CLASS_INNER_CLASS,
309 List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
310
311 /**
312 * The access flag {@code ACC_ENUM} with a mask value of
313 * <code>{@value "0x%04x" Modifier#ENUM}</code>.
314 * @see Class#isEnum()
315 */
316 ENUM(Modifier.ENUM, false, Location.SET_CLASS_FIELD_INNER_CLASS,
317 List.of(Map.entry(RELEASE_4, Location.EMPTY_SET))),
318
319 /**
320 * The access flag {@code ACC_MANDATED} with a mask value of
321 * <code>{@value "0x%04x" Modifier#MANDATED}</code>.
322 */
323 MANDATED(Modifier.MANDATED, false, Location.SET_MANDATED_9,
324 List.of(Map.entry(RELEASE_8, Location.SET_METHOD_PARAM),
325 Map.entry(RELEASE_7, Location.EMPTY_SET))),
326
327 /**
328 * The access flag {@code ACC_MODULE} with a mask value of {@code
329 * 0x8000}.
330 */
331 MODULE(0x0000_8000, false, Location.SET_CLASS,
332 List.of(Map.entry(RELEASE_8, Location.EMPTY_SET))),
333 ;
334
335 // May want to override toString for a different enum constant ->
336 // name mapping.
337
338 private final int mask;
339 private final boolean sourceModifier;
340
341 // immutable
342 private final Set<Location> locations;
343 // historical locations up to a given version; immutable
344 private final List<Map.Entry<ClassFileFormatVersion, Set<Location>>> historicalLocations;
345
346 private AccessFlag(int mask,
347 boolean sourceModifier,
348 Set<Location> locations,
349 List<Map.Entry<ClassFileFormatVersion, Set<Location>>> historicalLocations) {
350 this.mask = mask;
351 this.sourceModifier = sourceModifier;
352 this.locations = locations;
353 this.historicalLocations = Location.ensureHistoryOrdered(historicalLocations);
354 }
355
356 /**
357 * {@return the corresponding mask for the access flag} The mask has
358 * exactly one bit set and is in the range of {@code char}.
359 */
360 public int mask() {
361 return mask;
362 }
363
364 /**
365 * {@return whether or not this flag has a directly corresponding
366 * modifier in the Java programming language}
367 */
368 public boolean sourceModifier() {
369 return sourceModifier;
370 }
371
372 /**
373 * {@return locations this flag can be applied to in the current class file
374 * format version}
375 * <p>
376 * This method returns an empty set if this flag is not defined in
377 * the current class file format version.
378 */
379 public Set<Location> locations() {
380 return locations(latest());
381 }
382
383 /**
384 * {@return locations this flag can be applied to in the given class file
385 * format version}
386 * <p>
387 * This method returns an empty set if this flag is not defined in
388 * the given {@code cffv}.
389 *
390 * @param cffv the class file format version to use
391 * @throws NullPointerException if the parameter is {@code null}
392 */
393 public Set<Location> locations(ClassFileFormatVersion cffv) {
394 return Location.findInHistory(locations, historicalLocations, cffv);
395 }
396
397 /**
398 * {@return an unmodifiable set of access flags for the given mask value
399 * appropriate for the location in the current class file format version}
400 *
401 * @param mask bit mask of access flags
402 * @param location context to interpret mask value
403 * @throws IllegalArgumentException if the mask contains bit
404 * positions not defined for the location in the current class file format
405 * @throws NullPointerException if {@code location} is {@code null}
406 */
407 public static Set<AccessFlag> maskToAccessFlags(int mask, Location location) {
408 return maskToAccessFlags(mask, location, latest());
409 }
410
411 /**
412 * {@return an unmodifiable set of access flags for the given mask value
413 * appropriate for the location in the given class file format version}
414 *
415 * @param mask bit mask of access flags
416 * @param location context to interpret mask value
417 * @param cffv the class file format to interpret mask value
418 * @throws IllegalArgumentException if the mask contains bit
419 * positions not defined for the location in the given class file format
420 * @throws NullPointerException if {@code location} or {@code cffv} is {@code null}
421 * @since 25
422 */
423 public static Set<AccessFlag> maskToAccessFlags(int mask, Location location, ClassFileFormatVersion cffv) {
424 var definition = AccessFlagSet.findDefinition(location, cffv); // null checks location
425 int unmatchedMask = mask & (~location.flagsMask(cffv));
426 if (unmatchedMask != 0) {
427 throw new IllegalArgumentException("Unmatched bit position 0x" +
428 Integer.toHexString(unmatchedMask) +
429 " for location " + location +
430 " for class file format " + cffv);
431 }
432 return AccessFlagSet.ofValidated(definition, mask);
433 }
434
435 /**
436 * A location within a {@code class} file where flags can be applied.
437 * <p>
438 * Note that since these locations represent {@code class} file structures
439 * rather than language structures, many language structures, such
440 * as constructors and interfaces, are <em>not</em> present.
441 * @since 20
442 */
443 public enum Location {
444 /**
445 * Class location.
446 *
447 * @see Class#accessFlags()
448 * @see ClassModel#flags()
449 * @see Modifier#classModifiers()
450 * @see Modifier#interfaceModifiers()
451 * @jvms 4.1 The {@code ClassFile} Structure
452 */
453 CLASS(ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
454 ACC_INTERFACE | ACC_ABSTRACT |
455 ACC_SYNTHETIC | ACC_ANNOTATION |
456 ACC_ENUM | ACC_MODULE,
457 List.of(Map.entry(RELEASE_8, // no module
458 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
459 ACC_INTERFACE | ACC_ABSTRACT |
460 ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM),
461 Map.entry(RELEASE_4, // no synthetic, annotation, enum
462 ACC_PUBLIC | ACC_FINAL | ACC_SUPER |
463 ACC_INTERFACE | ACC_ABSTRACT))),
464
465 /**
466 * Field location.
467 *
468 * @see Field#accessFlags()
469 * @see FieldModel#flags()
470 * @see Modifier#fieldModifiers()
471 * @jvms 4.5 Fields
472 */
473 FIELD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
474 ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
475 ACC_TRANSIENT | ACC_SYNTHETIC | ACC_ENUM,
476 List.of(Map.entry(RELEASE_4, // no synthetic, enum
477 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
478 ACC_STATIC | ACC_FINAL | ACC_VOLATILE |
479 ACC_TRANSIENT))),
480
481 /**
482 * Method location.
483 *
484 * @see Executable#accessFlags()
485 * @see MethodModel#flags()
486 * @see Modifier#methodModifiers()
487 * @see Modifier#constructorModifiers()
488 * @jvms 4.6 Methods
489 */
490 METHOD(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
491 ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
492 ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
493 ACC_ABSTRACT | ACC_SYNTHETIC,
494 List.of(Map.entry(RELEASE_16, // had strict
495 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
496 ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
497 ACC_BRIDGE | ACC_VARARGS | ACC_NATIVE |
498 ACC_ABSTRACT | ACC_STRICT | ACC_SYNTHETIC),
499 Map.entry(RELEASE_4, // no bridge, varargs, synthetic
500 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
501 ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
502 ACC_NATIVE | ACC_ABSTRACT | ACC_STRICT),
503 Map.entry(RELEASE_1, // no strict
504 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
505 ACC_STATIC | ACC_FINAL | ACC_SYNCHRONIZED |
506 ACC_NATIVE | ACC_ABSTRACT))),
507
508 /**
509 * Inner class location.
510 *
511 * @see Class#accessFlags()
512 * @see InnerClassInfo#flags()
513 * @see Modifier#classModifiers()
514 * @see Modifier#interfaceModifiers()
515 * @jvms 4.7.6 The {@code InnerClasses} Attribute
516 */
517 INNER_CLASS(ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
518 ACC_STATIC | ACC_FINAL | ACC_INTERFACE | ACC_ABSTRACT |
519 ACC_SYNTHETIC | ACC_ANNOTATION | ACC_ENUM,
520 List.of(Map.entry(RELEASE_4, // no synthetic, annotation, enum
521 ACC_PUBLIC | ACC_PRIVATE | ACC_PROTECTED |
522 ACC_STATIC | ACC_FINAL | ACC_INTERFACE |
523 ACC_ABSTRACT),
524 Map.entry(RELEASE_0, 0))), // did not exist
525
526 /**
527 * Method parameter location.
528 *
529 * @see Parameter#accessFlags()
530 * @see MethodParameterInfo#flags()
531 * @see Modifier#parameterModifiers()
532 * @jvms 4.7.24 The {@code MethodParameters} Attribute
533 */
534 METHOD_PARAMETER(ACC_FINAL | ACC_SYNTHETIC | ACC_MANDATED,
535 List.of(Map.entry(RELEASE_7, 0))), // did not exist
536
537 /**
538 * Module location.
539 *
540 * @see ModuleDescriptor#accessFlags()
541 * @see ModuleAttribute#moduleFlags()
542 * @jvms 4.7.25 The {@code Module} Attribute
543 */
544 MODULE(ACC_OPEN | ACC_SYNTHETIC | ACC_MANDATED,
545 List.of(Map.entry(RELEASE_8, 0))), // did not exist
546
547 /**
548 * Module requires location.
549 *
550 * @see ModuleDescriptor.Requires#accessFlags()
551 * @see ModuleRequireInfo#requiresFlags()
552 * @jvms 4.7.25 The {@code Module} Attribute
553 */
554 MODULE_REQUIRES(ACC_TRANSITIVE | ACC_STATIC_PHASE | ACC_SYNTHETIC | ACC_MANDATED,
555 List.of(Map.entry(RELEASE_8, 0))), // did not exist
556
557 /**
558 * Module exports location.
559 *
560 * @see ModuleDescriptor.Exports#accessFlags()
561 * @see ModuleExportInfo#exportsFlags()
562 * @jvms 4.7.25 The {@code Module} Attribute
563 */
564 MODULE_EXPORTS(ACC_SYNTHETIC | ACC_MANDATED,
565 List.of(Map.entry(RELEASE_8, 0))), // did not exist
566
567 /**
568 * Module opens location.
569 *
570 * @see ModuleDescriptor.Opens#accessFlags()
571 * @see ModuleOpenInfo#opensFlags()
572 * @jvms 4.7.25 The {@code Module} Attribute
573 */
574 MODULE_OPENS(ACC_SYNTHETIC | ACC_MANDATED,
575 List.of(Map.entry(RELEASE_8, 0))), // did not exist
576 ;
577
578 // Repeated sets of locations used by AccessFlag constants
579 private static final Set<Location> EMPTY_SET = Set.of();
580 private static final Set<Location> SET_MODULE = Set.of(MODULE);
581 private static final Set<Location> SET_CLASS_METHOD_INNER_CLASS =
582 Set.of(CLASS, METHOD, INNER_CLASS);
583 private static final Set<Location> SET_CLASS_FIELD_METHOD =
584 Set.of(CLASS, FIELD, METHOD);
585 private static final Set<Location> SET_CLASS_FIELD_INNER_CLASS =
586 Set.of(CLASS, FIELD, INNER_CLASS);
587 private static final Set<Location> SET_CLASS_FIELD_METHOD_INNER_CLASS =
588 Set.of(CLASS, FIELD, METHOD, INNER_CLASS);
589 private static final Set<Location> SET_CLASS_METHOD =
590 Set.of(CLASS, METHOD);
591 private static final Set<Location> SET_FIELD_METHOD =
592 Set.of(FIELD, METHOD);
593 private static final Set<Location> SET_FIELD_METHOD_INNER_CLASS =
594 Set.of(FIELD, METHOD, INNER_CLASS);
595 private static final Set<Location> SET_METHOD = Set.of(METHOD);
596 private static final Set<Location> SET_METHOD_PARAM = Set.of(METHOD_PARAMETER);
597 private static final Set<Location> SET_FIELD = Set.of(FIELD);
598 private static final Set<Location> SET_CLASS = Set.of(CLASS);
599 private static final Set<Location> SET_CLASS_INNER_CLASS =
600 Set.of(CLASS, INNER_CLASS);
601 private static final Set<Location> SET_MODULE_REQUIRES =
602 Set.of(MODULE_REQUIRES);
603 private static final Set<Location> SET_FINAL_8 =
604 Set.of(CLASS, FIELD, METHOD,
605 INNER_CLASS, /* added in 1.1 */
606 METHOD_PARAMETER); /* added in 8 */
607 private static final Set<Location> SET_SYNTHETIC_5 =
608 Set.of(CLASS, FIELD, METHOD,
609 INNER_CLASS);
610 private static final Set<Location> SET_SYNTHETIC_8 =
611 Set.of(CLASS, FIELD, METHOD,
612 INNER_CLASS, METHOD_PARAMETER);
613 private static final Set<Location> SET_SYNTHETIC_9 =
614 // Added as an access flag in 5.0
615 Set.of(CLASS, FIELD, METHOD,
616 INNER_CLASS,
617 METHOD_PARAMETER, // Added in 8
618 // Module-related items added in 9
619 MODULE, MODULE_REQUIRES,
620 MODULE_EXPORTS, MODULE_OPENS);
621 private static final Set<Location> SET_MANDATED_9 =
622 Set.of(METHOD_PARAMETER, // From 8
623 // Starting in 9
624 MODULE, MODULE_REQUIRES,
625 MODULE_EXPORTS, MODULE_OPENS);
626
627 private final int flagsMask;
628 private final List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks;
629
630 Location(int flagsMask,
631 List<Map.Entry<ClassFileFormatVersion, Integer>> historicalFlagsMasks) {
632 this.flagsMask = flagsMask;
633 this.historicalFlagsMasks = ensureHistoryOrdered(historicalFlagsMasks);
634 }
635
636 // Ensures the historical versions are from newest to oldest and do not include the latest
637 // These 2 utilities reside in Location because Location must be initialized before AccessFlag
638 private static <T> List<Map.Entry<ClassFileFormatVersion, T>> ensureHistoryOrdered(
639 List<Map.Entry<ClassFileFormatVersion, T>> history) {
640 ClassFileFormatVersion lastVersion = latest();
641 for (var e : history) {
642 var historyVersion = e.getKey();
643 if (lastVersion.compareTo(historyVersion) <= 0) {
644 throw new IllegalArgumentException("Versions out of order");
645 }
646 lastVersion = historyVersion;
647 }
648 return history;
649 }
650
651 private static <T> T findInHistory(T candidate, List<Map.Entry<ClassFileFormatVersion, T>> history,
652 ClassFileFormatVersion cffv) {
653 Objects.requireNonNull(cffv);
654 for (var e : history) {
655 if (e.getKey().compareTo(cffv) < 0) {
656 // last version found was valid
657 return candidate;
658 }
659 candidate = e.getValue();
660 }
661 return candidate;
662 }
663
664 /**
665 * {@return the union of masks of all access flags defined for
666 * this location in the current class file format version}
667 * <p>
668 * This method returns {@code 0} if this location does not exist in
669 * the current class file format version.
670 *
671 * @since 25
672 */
673 public int flagsMask() {
674 return flagsMask(latest());
675 }
676
677 /**
678 * {@return the union of masks of all access flags defined for
679 * this location in the given class file format version}
680 * <p>
681 * This method returns {@code 0} if this location does not exist in
682 * the given {@code cffv}.
683 *
684 * @param cffv the class file format version
685 * @throws NullPointerException if {@code cffv} is {@code null}
686 * @since 25
687 */
688 public int flagsMask(ClassFileFormatVersion cffv) {
689 return findInHistory(flagsMask, historicalFlagsMasks, cffv);
690 }
691
692 /**
693 * {@return the set of access flags defined for this location in the
694 * current class file format version} The set is immutable.
695 * <p>
696 * This method returns an empty set if this location does not exist
697 * in the current class file format version.
698 *
699 * @since 25
700 */
701 public Set<AccessFlag> flags() {
702 return flags(latest());
703 }
704
705 /**
706 * {@return the set of access flags defined for this location in the
707 * given class file format version} The set is immutable.
708 * <p>
709 * This method returns an empty set if this location does not exist
710 * in the given {@code cffv}.
711 *
712 * @param cffv the class file format version
713 * @throws NullPointerException if {@code cffv} is {@code null}
714 * @since 25
715 */
716 public Set<AccessFlag> flags(ClassFileFormatVersion cffv) {
717 // flagsMask null checks cffv and always returns valid mask
718 return AccessFlagSet.ofValidated(AccessFlagSet.findDefinition(this, cffv), flagsMask(cffv));
719 }
720 }
721 }