1 /* 2 * Copyright (c) 1996, 2023, 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; 27 28 import jdk.internal.misc.CDS; 29 import jdk.internal.vm.annotation.IntrinsicCandidate; 30 import jdk.internal.vm.annotation.Stable; 31 32 import java.lang.constant.Constable; 33 import java.lang.constant.DynamicConstantDesc; 34 import java.util.Optional; 35 36 import static java.lang.constant.ConstantDescs.BSM_EXPLICIT_CAST; 37 import static java.lang.constant.ConstantDescs.CD_int; 38 import static java.lang.constant.ConstantDescs.CD_short; 39 import static java.lang.constant.ConstantDescs.DEFAULT_NAME; 40 41 /** 42 * The {@code Short} class wraps a value of primitive type {@code 43 * short} in an object. An object of type {@code Short} contains a 44 * single field whose type is {@code short}. 45 * 46 * <p>In addition, this class provides several methods for converting 47 * a {@code short} to a {@code String} and a {@code String} to a 48 * {@code short}, as well as other constants and methods useful when 49 * dealing with a {@code short}. 50 * 51 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a> 52 * class; programmers should treat instances that are 53 * {@linkplain #equals(Object) equal} as interchangeable and should not 54 * use instances for synchronization, or unpredictable behavior may 55 * occur. For example, in a future release, synchronization may fail. 56 * 57 * @author Nakul Saraiya 58 * @author Joseph D. Darcy 59 * @see java.lang.Number 60 * @since 1.1 61 */ 62 @jdk.internal.ValueBased 63 public final class Short extends Number implements Comparable<Short>, Constable { 64 65 /** 66 * A constant holding the minimum value a {@code short} can 67 * have, -2<sup>15</sup>. 68 */ 69 public static final short MIN_VALUE = -32768; 70 71 /** 72 * A constant holding the maximum value a {@code short} can 73 * have, 2<sup>15</sup>-1. 74 */ 75 public static final short MAX_VALUE = 32767; 76 77 /** 78 * The {@code Class} instance representing the primitive type 79 * {@code short}. 80 */ 81 @SuppressWarnings("unchecked") 82 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short"); 83 84 /** 85 * Returns a new {@code String} object representing the 86 * specified {@code short}. The radix is assumed to be 10. 87 * 88 * @param s the {@code short} to be converted 89 * @return the string representation of the specified {@code short} 90 * @see java.lang.Integer#toString(int) 91 */ 92 public static String toString(short s) { 93 return Integer.toString(s); 94 } 95 96 /** 97 * Parses the string argument as a signed {@code short} in the 98 * radix specified by the second argument. The characters in the 99 * string must all be digits, of the specified radix (as 100 * determined by whether {@link java.lang.Character#digit(char, 101 * int)} returns a nonnegative value) except that the first 102 * character may be an ASCII minus sign {@code '-'} 103 * ({@code '\u005Cu002D'}) to indicate a negative value or an 104 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 105 * indicate a positive value. The resulting {@code short} value 106 * is returned. 107 * 108 * <p>An exception of type {@code NumberFormatException} is 109 * thrown if any of the following situations occurs: 110 * <ul> 111 * <li> The first argument is {@code null} or is a string of 112 * length zero. 113 * 114 * <li> The radix is either smaller than {@link 115 * java.lang.Character#MIN_RADIX} or larger than {@link 116 * java.lang.Character#MAX_RADIX}. 117 * 118 * <li> Any character of the string is not a digit of the 119 * specified radix, except that the first character may be a minus 120 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign 121 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 122 * string is longer than length 1. 123 * 124 * <li> The value represented by the string is not a value of type 125 * {@code short}. 126 * </ul> 127 * 128 * @param s the {@code String} containing the 129 * {@code short} representation to be parsed 130 * @param radix the radix to be used while parsing {@code s} 131 * @return the {@code short} represented by the string 132 * argument in the specified radix. 133 * @throws NumberFormatException If the {@code String} 134 * does not contain a parsable {@code short}. 135 */ 136 public static short parseShort(String s, int radix) 137 throws NumberFormatException { 138 int i = Integer.parseInt(s, radix); 139 if (i < MIN_VALUE || i > MAX_VALUE) 140 throw new NumberFormatException( 141 "Value out of range. Value:\"" + s + "\" Radix:" + radix); 142 return (short)i; 143 } 144 145 /** 146 * Parses the string argument as a signed decimal {@code 147 * short}. The characters in the string must all be decimal 148 * digits, except that the first character may be an ASCII minus 149 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a 150 * negative value or an ASCII plus sign {@code '+'} 151 * ({@code '\u005Cu002B'}) to indicate a positive value. The 152 * resulting {@code short} value is returned, exactly as if the 153 * argument and the radix 10 were given as arguments to the {@link 154 * #parseShort(java.lang.String, int)} method. 155 * 156 * @param s a {@code String} containing the {@code short} 157 * representation to be parsed 158 * @return the {@code short} value represented by the 159 * argument in decimal. 160 * @throws NumberFormatException If the string does not 161 * contain a parsable {@code short}. 162 */ 163 public static short parseShort(String s) throws NumberFormatException { 164 return parseShort(s, 10); 165 } 166 167 /** 168 * Returns a {@code Short} object holding the value 169 * extracted from the specified {@code String} when parsed 170 * with the radix given by the second argument. The first argument 171 * is interpreted as representing a signed {@code short} in 172 * the radix specified by the second argument, exactly as if the 173 * argument were given to the {@link #parseShort(java.lang.String, 174 * int)} method. The result is a {@code Short} object that 175 * represents the {@code short} value specified by the string. 176 * 177 * <p>In other words, this method returns a {@code Short} object 178 * equal to the value of: 179 * 180 * <blockquote> 181 * {@code Short.valueOf(Short.parseShort(s, radix))} 182 * </blockquote> 183 * 184 * @param s the string to be parsed 185 * @param radix the radix to be used in interpreting {@code s} 186 * @return a {@code Short} object holding the value 187 * represented by the string argument in the 188 * specified radix. 189 * @throws NumberFormatException If the {@code String} does 190 * not contain a parsable {@code short}. 191 */ 192 public static Short valueOf(String s, int radix) 193 throws NumberFormatException { 194 return valueOf(parseShort(s, radix)); 195 } 196 197 /** 198 * Returns a {@code Short} object holding the 199 * value given by the specified {@code String}. The argument 200 * is interpreted as representing a signed decimal 201 * {@code short}, exactly as if the argument were given to 202 * the {@link #parseShort(java.lang.String)} method. The result is 203 * a {@code Short} object that represents the 204 * {@code short} value specified by the string. 205 * 206 * <p>In other words, this method returns a {@code Short} object 207 * equal to the value of: 208 * 209 * <blockquote> 210 * {@code Short.valueOf(Short.parseShort(s))} 211 * </blockquote> 212 * 213 * @param s the string to be parsed 214 * @return a {@code Short} object holding the value 215 * represented by the string argument 216 * @throws NumberFormatException If the {@code String} does 217 * not contain a parsable {@code short}. 218 */ 219 public static Short valueOf(String s) throws NumberFormatException { 220 return valueOf(s, 10); 221 } 222 223 /** 224 * Returns an {@link Optional} containing the nominal descriptor for this 225 * instance. 226 * 227 * @return an {@link Optional} describing the {@linkplain Short} instance 228 * @since 15 229 */ 230 @Override 231 public Optional<DynamicConstantDesc<Short>> describeConstable() { 232 return Optional.of(DynamicConstantDesc.ofNamed(BSM_EXPLICIT_CAST, DEFAULT_NAME, CD_short, intValue())); 233 } 234 235 private static final class ShortCache { 236 private ShortCache() {} 237 238 @Stable 239 static final Short[] cache; 240 static Short[] archivedCache; 241 242 static { 243 int size = -(-128) + 127 + 1; 244 245 // Load and use the archived cache if it exists 246 CDS.initializeFromArchive(ShortCache.class); 247 if (archivedCache == null || archivedCache.length != size) { 248 Short[] c = new Short[size]; 249 short value = -128; 250 for(int i = 0; i < size; i++) { 251 c[i] = new Short(value++); 252 } 253 archivedCache = c; 254 } 255 cache = archivedCache; 256 } 257 } 258 259 /** 260 * Returns a {@code Short} instance representing the specified 261 * {@code short} value. 262 * If a new {@code Short} instance is not required, this method 263 * should generally be used in preference to the constructor 264 * {@link #Short(short)}, as this method is likely to yield 265 * significantly better space and time performance by caching 266 * frequently requested values. 267 * 268 * This method will always cache values in the range -128 to 127, 269 * inclusive, and may cache other values outside of this range. 270 * 271 * @param s a short value. 272 * @return a {@code Short} instance representing {@code s}. 273 * @since 1.5 274 */ 275 @IntrinsicCandidate 276 public static Short valueOf(short s) { 277 final int offset = 128; 278 int sAsInt = s; 279 if (sAsInt >= -128 && sAsInt <= 127) { // must cache 280 return ShortCache.cache[sAsInt + offset]; 281 } 282 return new Short(s); 283 } 284 285 /** 286 * Decodes a {@code String} into a {@code Short}. 287 * Accepts decimal, hexadecimal, and octal numbers given by 288 * the following grammar: 289 * 290 * <blockquote> 291 * <dl> 292 * <dt><i>DecodableString:</i> 293 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 294 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 295 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 296 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 297 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 298 * 299 * <dt><i>Sign:</i> 300 * <dd>{@code -} 301 * <dd>{@code +} 302 * </dl> 303 * </blockquote> 304 * 305 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 306 * are as defined in section {@jls 3.10.1} of 307 * <cite>The Java Language Specification</cite>, 308 * except that underscores are not accepted between digits. 309 * 310 * <p>The sequence of characters following an optional 311 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 312 * "{@code #}", or leading zero) is parsed as by the {@code 313 * Short.parseShort} method with the indicated radix (10, 16, or 314 * 8). This sequence of characters must represent a positive 315 * value or a {@link NumberFormatException} will be thrown. The 316 * result is negated if first character of the specified {@code 317 * String} is the minus sign. No whitespace characters are 318 * permitted in the {@code String}. 319 * 320 * @param nm the {@code String} to decode. 321 * @return a {@code Short} object holding the {@code short} 322 * value represented by {@code nm} 323 * @throws NumberFormatException if the {@code String} does not 324 * contain a parsable {@code short}. 325 * @see java.lang.Short#parseShort(java.lang.String, int) 326 */ 327 public static Short decode(String nm) throws NumberFormatException { 328 int i = Integer.decode(nm); 329 if (i < MIN_VALUE || i > MAX_VALUE) 330 throw new NumberFormatException( 331 "Value " + i + " out of range from input " + nm); 332 return valueOf((short)i); 333 } 334 335 /** 336 * The value of the {@code Short}. 337 * 338 * @serial 339 */ 340 private final short value; 341 342 /** 343 * Constructs a newly allocated {@code Short} object that 344 * represents the specified {@code short} value. 345 * 346 * @param value the value to be represented by the 347 * {@code Short}. 348 * 349 * @deprecated 350 * It is rarely appropriate to use this constructor. The static factory 351 * {@link #valueOf(short)} is generally a better choice, as it is 352 * likely to yield significantly better space and time performance. 353 */ 354 @Deprecated(since="9", forRemoval = true) 355 public Short(short value) { 356 this.value = value; 357 } 358 359 /** 360 * Constructs a newly allocated {@code Short} object that 361 * represents the {@code short} value indicated by the 362 * {@code String} parameter. The string is converted to a 363 * {@code short} value in exactly the manner used by the 364 * {@code parseShort} method for radix 10. 365 * 366 * @param s the {@code String} to be converted to a 367 * {@code Short} 368 * @throws NumberFormatException If the {@code String} 369 * does not contain a parsable {@code short}. 370 * 371 * @deprecated 372 * It is rarely appropriate to use this constructor. 373 * Use {@link #parseShort(String)} to convert a string to a 374 * {@code short} primitive, or use {@link #valueOf(String)} 375 * to convert a string to a {@code Short} object. 376 */ 377 @Deprecated(since="9", forRemoval = true) 378 public Short(String s) throws NumberFormatException { 379 this.value = parseShort(s, 10); 380 } 381 382 /** 383 * Returns the value of this {@code Short} as a {@code byte} after 384 * a narrowing primitive conversion. 385 * @jls 5.1.3 Narrowing Primitive Conversion 386 */ 387 public byte byteValue() { 388 return (byte)value; 389 } 390 391 /** 392 * Returns the value of this {@code Short} as a 393 * {@code short}. 394 */ 395 @IntrinsicCandidate 396 public short shortValue() { 397 return value; 398 } 399 400 /** 401 * Returns the value of this {@code Short} as an {@code int} after 402 * a widening primitive conversion. 403 * @jls 5.1.2 Widening Primitive Conversion 404 */ 405 public int intValue() { 406 return (int)value; 407 } 408 409 /** 410 * Returns the value of this {@code Short} as a {@code long} after 411 * a widening primitive conversion. 412 * @jls 5.1.2 Widening Primitive Conversion 413 */ 414 public long longValue() { 415 return (long)value; 416 } 417 418 /** 419 * Returns the value of this {@code Short} as a {@code float} 420 * after a widening primitive conversion. 421 * @jls 5.1.2 Widening Primitive Conversion 422 */ 423 public float floatValue() { 424 return (float)value; 425 } 426 427 /** 428 * Returns the value of this {@code Short} as a {@code double} 429 * after a widening primitive conversion. 430 * @jls 5.1.2 Widening Primitive Conversion 431 */ 432 public double doubleValue() { 433 return (double)value; 434 } 435 436 /** 437 * Returns a {@code String} object representing this 438 * {@code Short}'s value. The value is converted to signed 439 * decimal representation and returned as a string, exactly as if 440 * the {@code short} value were given as an argument to the 441 * {@link java.lang.Short#toString(short)} method. 442 * 443 * @return a string representation of the value of this object in 444 * base 10. 445 */ 446 @Override 447 public String toString() { 448 return Integer.toString(value); 449 } 450 451 /** 452 * Returns a hash code for this {@code Short}; equal to the result 453 * of invoking {@code intValue()}. 454 * 455 * @return a hash code value for this {@code Short} 456 */ 457 @Override 458 public int hashCode() { 459 return Short.hashCode(value); 460 } 461 462 /** 463 * Returns a hash code for a {@code short} value; compatible with 464 * {@code Short.hashCode()}. 465 * 466 * @param value the value to hash 467 * @return a hash code value for a {@code short} value. 468 * @since 1.8 469 */ 470 public static int hashCode(short value) { 471 return (int)value; 472 } 473 474 /** 475 * Compares this object to the specified object. The result is 476 * {@code true} if and only if the argument is not 477 * {@code null} and is a {@code Short} object that 478 * contains the same {@code short} value as this object. 479 * 480 * @param obj the object to compare with 481 * @return {@code true} if the objects are the same; 482 * {@code false} otherwise. 483 */ 484 public boolean equals(Object obj) { 485 if (obj instanceof Short) { 486 return value == ((Short)obj).shortValue(); 487 } 488 return false; 489 } 490 491 /** 492 * Compares two {@code Short} objects numerically. 493 * 494 * @param anotherShort the {@code Short} to be compared. 495 * @return the value {@code 0} if this {@code Short} is 496 * equal to the argument {@code Short}; a value less than 497 * {@code 0} if this {@code Short} is numerically less 498 * than the argument {@code Short}; and a value greater than 499 * {@code 0} if this {@code Short} is numerically 500 * greater than the argument {@code Short} (signed 501 * comparison). 502 * @since 1.2 503 */ 504 public int compareTo(Short anotherShort) { 505 return compare(this.value, anotherShort.value); 506 } 507 508 /** 509 * Compares two {@code short} values numerically. 510 * The value returned is identical to what would be returned by: 511 * <pre> 512 * Short.valueOf(x).compareTo(Short.valueOf(y)) 513 * </pre> 514 * 515 * @param x the first {@code short} to compare 516 * @param y the second {@code short} to compare 517 * @return the value {@code 0} if {@code x == y}; 518 * a value less than {@code 0} if {@code x < y}; and 519 * a value greater than {@code 0} if {@code x > y} 520 * @since 1.7 521 */ 522 public static int compare(short x, short y) { 523 return x - y; 524 } 525 526 /** 527 * Compares two {@code short} values numerically treating the values 528 * as unsigned. 529 * 530 * @param x the first {@code short} to compare 531 * @param y the second {@code short} to compare 532 * @return the value {@code 0} if {@code x == y}; a value less 533 * than {@code 0} if {@code x < y} as unsigned values; and 534 * a value greater than {@code 0} if {@code x > y} as 535 * unsigned values 536 * @since 9 537 */ 538 public static int compareUnsigned(short x, short y) { 539 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y); 540 } 541 542 /** 543 * The number of bits used to represent a {@code short} value in two's 544 * complement binary form. 545 * @since 1.5 546 */ 547 public static final int SIZE = 16; 548 549 /** 550 * The number of bytes used to represent a {@code short} value in two's 551 * complement binary form. 552 * 553 * @since 1.8 554 */ 555 public static final int BYTES = SIZE / Byte.SIZE; 556 557 /** 558 * Returns the value obtained by reversing the order of the bytes in the 559 * two's complement representation of the specified {@code short} value. 560 * 561 * @param i the value whose bytes are to be reversed 562 * @return the value obtained by reversing (or, equivalently, swapping) 563 * the bytes in the specified {@code short} value. 564 * @since 1.5 565 */ 566 @IntrinsicCandidate 567 public static short reverseBytes(short i) { 568 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 569 } 570 571 572 /** 573 * Converts the argument to an {@code int} by an unsigned 574 * conversion. In an unsigned conversion to an {@code int}, the 575 * high-order 16 bits of the {@code int} are zero and the 576 * low-order 16 bits are equal to the bits of the {@code short} argument. 577 * 578 * Consequently, zero and positive {@code short} values are mapped 579 * to a numerically equal {@code int} value and negative {@code 580 * short} values are mapped to an {@code int} value equal to the 581 * input plus 2<sup>16</sup>. 582 * 583 * @param x the value to convert to an unsigned {@code int} 584 * @return the argument converted to {@code int} by an unsigned 585 * conversion 586 * @since 1.8 587 */ 588 public static int toUnsignedInt(short x) { 589 return ((int) x) & 0xffff; 590 } 591 592 /** 593 * Converts the argument to a {@code long} by an unsigned 594 * conversion. In an unsigned conversion to a {@code long}, the 595 * high-order 48 bits of the {@code long} are zero and the 596 * low-order 16 bits are equal to the bits of the {@code short} argument. 597 * 598 * Consequently, zero and positive {@code short} values are mapped 599 * to a numerically equal {@code long} value and negative {@code 600 * short} values are mapped to a {@code long} value equal to the 601 * input plus 2<sup>16</sup>. 602 * 603 * @param x the value to convert to an unsigned {@code long} 604 * @return the argument converted to {@code long} by an unsigned 605 * conversion 606 * @since 1.8 607 */ 608 public static long toUnsignedLong(short x) { 609 return ((long) x) & 0xffffL; 610 } 611 612 /** use serialVersionUID from JDK 1.1. for interoperability */ 613 @java.io.Serial 614 private static final long serialVersionUID = 7515723908773894738L; 615 }