1 /* 2 * Copyright (c) 1996, 2012, 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 /** 29 * The {@code Short} class wraps a value of primitive type {@code 30 * short} in an object. An object of type {@code Short} contains a 31 * single field whose type is {@code short}. 32 * 33 * <p>In addition, this class provides several methods for converting 34 * a {@code short} to a {@code String} and a {@code String} to a 35 * {@code short}, as well as other constants and methods useful when 36 * dealing with a {@code short}. 37 * 38 * @author Nakul Saraiya 39 * @author Joseph D. Darcy 40 * @see java.lang.Number 41 * @since JDK1.1 42 */ 43 public final class Short extends Number implements Comparable<Short> { 44 45 /** 46 * A constant holding the minimum value a {@code short} can 47 * have, -2<sup>15</sup>. 48 */ 49 public static final short MIN_VALUE = -32768; 50 51 /** 52 * A constant holding the maximum value a {@code short} can 53 * have, 2<sup>15</sup>-1. 54 */ 55 public static final short MAX_VALUE = 32767; 56 57 /** 58 * The {@code Class} instance representing the primitive type 59 * {@code short}. 60 */ 61 @SuppressWarnings("unchecked") 62 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short"); 63 64 /** 65 * Returns a new {@code String} object representing the 66 * specified {@code short}. The radix is assumed to be 10. 67 * 68 * @param s the {@code short} to be converted 69 * @return the string representation of the specified {@code short} 70 * @see java.lang.Integer#toString(int) 71 */ 72 public static String toString(short s) { 73 return Integer.toString((int)s, 10); 74 } 75 76 /** 77 * Parses the string argument as a signed {@code short} in the 78 * radix specified by the second argument. The characters in the 79 * string must all be digits, of the specified radix (as 80 * determined by whether {@link java.lang.Character#digit(char, 81 * int)} returns a nonnegative value) except that the first 82 * character may be an ASCII minus sign {@code '-'} 83 * ({@code '\u005Cu002D'}) to indicate a negative value or an 84 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 85 * indicate a positive value. The resulting {@code short} value 86 * is returned. 87 * 88 * <p>An exception of type {@code NumberFormatException} is 89 * thrown if any of the following situations occurs: 90 * <ul> 91 * <li> The first argument is {@code null} or is a string of 92 * length zero. 93 * 94 * <li> The radix is either smaller than {@link 95 * java.lang.Character#MIN_RADIX} or larger than {@link 96 * java.lang.Character#MAX_RADIX}. 97 * 98 * <li> Any character of the string is not a digit of the 99 * specified radix, except that the first character may be a minus 100 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign 101 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 102 * string is longer than length 1. 103 * 104 * <li> The value represented by the string is not a value of type 105 * {@code short}. 106 * </ul> 107 * 108 * @param s the {@code String} containing the 109 * {@code short} representation to be parsed 110 * @param radix the radix to be used while parsing {@code s} 111 * @return the {@code short} represented by the string 112 * argument in the specified radix. 113 * @throws NumberFormatException If the {@code String} 114 * does not contain a parsable {@code short}. 115 */ 116 public static short parseShort(String s, int radix) 117 throws NumberFormatException { 118 int i = Integer.parseInt(s, radix); 119 if (i < MIN_VALUE || i > MAX_VALUE) 120 throw new NumberFormatException( 121 "Value out of range. Value:\"" + s + "\" Radix:" + radix); 122 return (short)i; 123 } 124 125 /** 126 * Parses the string argument as a signed decimal {@code 127 * short}. The characters in the string must all be decimal 128 * digits, except that the first character may be an ASCII minus 129 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a 130 * negative value or an ASCII plus sign {@code '+'} 131 * ({@code '\u005Cu002B'}) to indicate a positive value. The 132 * resulting {@code short} value is returned, exactly as if the 133 * argument and the radix 10 were given as arguments to the {@link 134 * #parseShort(java.lang.String, int)} method. 135 * 136 * @param s a {@code String} containing the {@code short} 137 * representation to be parsed 138 * @return the {@code short} value represented by the 139 * argument in decimal. 140 * @throws NumberFormatException If the string does not 141 * contain a parsable {@code short}. 142 */ 143 public static short parseShort(String s) throws NumberFormatException { 144 return parseShort(s, 10); 145 } 146 147 /** 148 * Returns a {@code Short} object holding the value 149 * extracted from the specified {@code String} when parsed 150 * with the radix given by the second argument. The first argument 151 * is interpreted as representing a signed {@code short} in 152 * the radix specified by the second argument, exactly as if the 153 * argument were given to the {@link #parseShort(java.lang.String, 154 * int)} method. The result is a {@code Short} object that 155 * represents the {@code short} value specified by the string. 156 * 157 * <p>In other words, this method returns a {@code Short} object 158 * equal to the value of: 159 * 160 * <blockquote> 161 * {@code new Short(Short.parseShort(s, radix))} 162 * </blockquote> 163 * 164 * @param s the string to be parsed 165 * @param radix the radix to be used in interpreting {@code s} 166 * @return a {@code Short} object holding the value 167 * represented by the string argument in the 168 * specified radix. 169 * @throws NumberFormatException If the {@code String} does 170 * not contain a parsable {@code short}. 171 */ 172 public static Short valueOf(String s, int radix) 173 throws NumberFormatException { 174 return valueOf(parseShort(s, radix)); 175 } 176 177 /** 178 * Returns a {@code Short} object holding the 179 * value given by the specified {@code String}. The argument 180 * is interpreted as representing a signed decimal 181 * {@code short}, exactly as if the argument were given to 182 * the {@link #parseShort(java.lang.String)} method. The result is 183 * a {@code Short} object that represents the 184 * {@code short} value specified by the string. 185 * 186 * <p>In other words, this method returns a {@code Short} object 187 * equal to the value of: 188 * 189 * <blockquote> 190 * {@code new Short(Short.parseShort(s))} 191 * </blockquote> 192 * 193 * @param s the string to be parsed 194 * @return a {@code Short} object holding the value 195 * represented by the string argument 196 * @throws NumberFormatException If the {@code String} does 197 * not contain a parsable {@code short}. 198 */ 199 public static Short valueOf(String s) throws NumberFormatException { 200 return valueOf(s, 10); 201 } 202 203 private static class ShortCache { 204 private ShortCache(){} 205 206 static final Short cache[] = new Short[-(-128) + 127 + 1]; 207 208 static { 209 for(int i = 0; i < cache.length; i++) 210 cache[i] = new Short((short)(i - 128)); 211 } 212 } 213 214 /** 215 * Returns a {@code Short} instance representing the specified 216 * {@code short} value. 217 * If a new {@code Short} instance is not required, this method 218 * should generally be used in preference to the constructor 219 * {@link #Short(short)}, as this method is likely to yield 220 * significantly better space and time performance by caching 221 * frequently requested values. 222 * 223 * This method will always cache values in the range -128 to 127, 224 * inclusive, and may cache other values outside of this range. 225 * 226 * @param s a short value. 227 * @return a {@code Short} instance representing {@code s}. 228 * @since 1.5 229 */ 230 public static Short valueOf(short s) { 231 final int offset = 128; 232 int sAsInt = s; 233 if (sAsInt >= -128 && sAsInt <= 127) { // must cache 234 return ShortCache.cache[sAsInt + offset]; 235 } 236 return new Short(s); 237 } 238 239 /** 240 * Decodes a {@code String} into a {@code Short}. 241 * Accepts decimal, hexadecimal, and octal numbers given by 242 * the following grammar: 243 * 244 * <blockquote> 245 * <dl> 246 * <dt><i>DecodableString:</i> 247 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 248 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 249 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 250 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 251 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 252 * <p> 253 * <dt><i>Sign:</i> 254 * <dd>{@code -} 255 * <dd>{@code +} 256 * </dl> 257 * </blockquote> 258 * 259 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 260 * are as defined in section 3.10.1 of 261 * <cite>The Java™ Language Specification</cite>, 262 * except that underscores are not accepted between digits. 263 * 264 * <p>The sequence of characters following an optional 265 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 266 * "{@code #}", or leading zero) is parsed as by the {@code 267 * Short.parseShort} method with the indicated radix (10, 16, or 268 * 8). This sequence of characters must represent a positive 269 * value or a {@link NumberFormatException} will be thrown. The 270 * result is negated if first character of the specified {@code 271 * String} is the minus sign. No whitespace characters are 272 * permitted in the {@code String}. 273 * 274 * @param nm the {@code String} to decode. 275 * @return a {@code Short} object holding the {@code short} 276 * value represented by {@code nm} 277 * @throws NumberFormatException if the {@code String} does not 278 * contain a parsable {@code short}. 279 * @see java.lang.Short#parseShort(java.lang.String, int) 280 */ 281 public static Short decode(String nm) throws NumberFormatException { 282 int i = Integer.decode(nm); 283 if (i < MIN_VALUE || i > MAX_VALUE) 284 throw new NumberFormatException( 285 "Value " + i + " out of range from input " + nm); 286 return valueOf((short)i); 287 } 288 289 /** 290 * The value of the {@code Short}. 291 * 292 * @serial 293 */ 294 private final short value; 295 296 /** 297 * Constructs a newly allocated {@code Short} object that 298 * represents the specified {@code short} value. 299 * 300 * @param value the value to be represented by the 301 * {@code Short}. 302 */ 303 public Short(short value) { 304 this.value = value; 305 } 306 307 /** 308 * Constructs a newly allocated {@code Short} object that 309 * represents the {@code short} value indicated by the 310 * {@code String} parameter. The string is converted to a 311 * {@code short} value in exactly the manner used by the 312 * {@code parseShort} method for radix 10. 313 * 314 * @param s the {@code String} to be converted to a 315 * {@code Short} 316 * @throws NumberFormatException If the {@code String} 317 * does not contain a parsable {@code short}. 318 * @see java.lang.Short#parseShort(java.lang.String, int) 319 */ 320 public Short(String s) throws NumberFormatException { 321 this.value = parseShort(s, 10); 322 } 323 324 /** 325 * Returns the value of this {@code Short} as a {@code byte} after 326 * a narrowing primitive conversion. 327 * @jls 5.1.3 Narrowing Primitive Conversions 328 */ 329 public byte byteValue() { 330 return (byte)value; 331 } 332 333 /** 334 * Returns the value of this {@code Short} as a 335 * {@code short}. 336 */ 337 public short shortValue() { 338 return value; 339 } 340 341 /** 342 * Returns the value of this {@code Short} as an {@code int} after 343 * a widening primitive conversion. 344 * @jls 5.1.2 Widening Primitive Conversions 345 */ 346 public int intValue() { 347 return (int)value; 348 } 349 350 /** 351 * Returns the value of this {@code Short} as a {@code long} after 352 * a widening primitive conversion. 353 * @jls 5.1.2 Widening Primitive Conversions 354 */ 355 public long longValue() { 356 return (long)value; 357 } 358 359 /** 360 * Returns the value of this {@code Short} as a {@code float} 361 * after a widening primitive conversion. 362 * @jls 5.1.2 Widening Primitive Conversions 363 */ 364 public float floatValue() { 365 return (float)value; 366 } 367 368 /** 369 * Returns the value of this {@code Short} as a {@code double} 370 * after a widening primitive conversion. 371 * @jls 5.1.2 Widening Primitive Conversions 372 */ 373 public double doubleValue() { 374 return (double)value; 375 } 376 377 /** 378 * Returns a {@code String} object representing this 379 * {@code Short}'s value. The value is converted to signed 380 * decimal representation and returned as a string, exactly as if 381 * the {@code short} value were given as an argument to the 382 * {@link java.lang.Short#toString(short)} method. 383 * 384 * @return a string representation of the value of this object in 385 * base 10. 386 */ 387 public String toString() { 388 return Integer.toString((int)value); 389 } 390 391 /** 392 * Returns a hash code for this {@code Short}; equal to the result 393 * of invoking {@code intValue()}. 394 * 395 * @return a hash code value for this {@code Short} 396 */ 397 @Override 398 public int hashCode() { 399 return Short.hashCode(value); 400 } 401 402 /** 403 * Returns a hash code for a {@code short} value; compatible with 404 * {@code Short.hashCode()}. 405 * 406 * @since 1.8 407 * 408 * @return a hash code value for a {@code short} value. 409 */ 410 public static int hashCode(short value) { 411 return (int)value; 412 } 413 414 /** 415 * Compares this object to the specified object. The result is 416 * {@code true} if and only if the argument is not 417 * {@code null} and is a {@code Short} object that 418 * contains the same {@code short} value as this object. 419 * 420 * @param obj the object to compare with 421 * @return {@code true} if the objects are the same; 422 * {@code false} otherwise. 423 */ 424 public boolean equals(Object obj) { 425 if (obj instanceof Short) { 426 return value == ((Short)obj).shortValue(); 427 } 428 return false; 429 } 430 431 /** 432 * Compares two {@code Short} objects numerically. 433 * 434 * @param anotherShort the {@code Short} to be compared. 435 * @return the value {@code 0} if this {@code Short} is 436 * equal to the argument {@code Short}; a value less than 437 * {@code 0} if this {@code Short} is numerically less 438 * than the argument {@code Short}; and a value greater than 439 * {@code 0} if this {@code Short} is numerically 440 * greater than the argument {@code Short} (signed 441 * comparison). 442 * @since 1.2 443 */ 444 public int compareTo(Short anotherShort) { 445 return compare(this.value, anotherShort.value); 446 } 447 448 /** 449 * Compares two {@code short} values numerically. 450 * The value returned is identical to what would be returned by: 451 * <pre> 452 * Short.valueOf(x).compareTo(Short.valueOf(y)) 453 * </pre> 454 * 455 * @param x the first {@code short} to compare 456 * @param y the second {@code short} to compare 457 * @return the value {@code 0} if {@code x == y}; 458 * a value less than {@code 0} if {@code x < y}; and 459 * a value greater than {@code 0} if {@code x > y} 460 * @since 1.7 461 */ 462 public static int compare(short x, short y) { 463 return x - y; 464 } 465 466 /** 467 * The number of bits used to represent a {@code short} value in two's 468 * complement binary form. 469 * @since 1.5 470 */ 471 public static final int SIZE = 16; 472 473 /** 474 * The number of bytes used to represent a {@code short} value in two's 475 * complement binary form. 476 * 477 * @since 1.8 478 */ 479 public static final int BYTES = SIZE / Byte.SIZE; 480 481 /** 482 * Returns the value obtained by reversing the order of the bytes in the 483 * two's complement representation of the specified {@code short} value. 484 * 485 * @return the value obtained by reversing (or, equivalently, swapping) 486 * the bytes in the specified {@code short} value. 487 * @since 1.5 488 */ 489 public static short reverseBytes(short i) { 490 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 491 } 492 493 494 /** 495 * Converts the argument to an {@code int} by an unsigned 496 * conversion. In an unsigned conversion to an {@code int}, the 497 * high-order 16 bits of the {@code int} are zero and the 498 * low-order 16 bits are equal to the bits of the {@code short} argument. 499 * 500 * Consequently, zero and positive {@code short} values are mapped 501 * to a numerically equal {@code int} value and negative {@code 502 * short} values are mapped to an {@code int} value equal to the 503 * input plus 2<sup>16</sup>. 504 * 505 * @param x the value to convert to an unsigned {@code int} 506 * @return the argument converted to {@code int} by an unsigned 507 * conversion 508 * @since 1.8 509 */ 510 public static int toUnsignedInt(short x) { 511 return ((int) x) & 0xffff; 512 } 513 514 /** 515 * Converts the argument to a {@code long} by an unsigned 516 * conversion. In an unsigned conversion to a {@code long}, the 517 * high-order 48 bits of the {@code long} are zero and the 518 * low-order 16 bits are equal to the bits of the {@code short} argument. 519 * 520 * Consequently, zero and positive {@code short} values are mapped 521 * to a numerically equal {@code long} value and negative {@code 522 * short} values are mapped to a {@code long} value equal to the 523 * input plus 2<sup>16</sup>. 524 * 525 * @param x the value to convert to an unsigned {@code long} 526 * @return the argument converted to {@code long} by an unsigned 527 * conversion 528 * @since 1.8 529 */ 530 public static long toUnsignedLong(short x) { 531 return ((long) x) & 0xffffL; 532 } 533 534 /** 535 * Adds two {@code short} values together as per the + operator. 536 * Suitable for conversion as a method reference to functional interfaces such 537 * as {@code BinaryOperator<Short>}. 538 * 539 * @param a an argument. 540 * @param b another argument. 541 * @return the sum of {@code a} and {@code b}. 542 * @since 1.8 543 */ 544 public static short sum(short a, short b) { 545 return (short) (a + b); 546 } 547 548 /** 549 * Returns the greater of two {@code short} values. 550 * Suitable for conversion as a method reference to functional interfaces such 551 * as {@code BinaryOperator<Short>}. 552 * 553 * @param a an argument. 554 * @param b another argument. 555 * @return the larger of {@code a} and {@code b}. 556 * @since 1.8 557 */ 558 public static short max(short a, short b) { 559 return (a >= b) ? a : b; 560 } 561 562 /** 563 * Returns the lesser of two {@code short} values. 564 * Suitable for conversion as a method reference to functional interfaces such 565 * as {@code BinaryOperator<Short>}. 566 * 567 * @param a an argument. 568 * @param b another argument. 569 * @return the lesser of {@code a} and {@code b}. 570 * @since 1.8 571 */ 572 public static short min(short a, short b) { 573 return (a <= b) ? a : b; 574 } 575 576 /** use serialVersionUID from JDK 1.1. for interoperability */ 577 private static final long serialVersionUID = 7515723908773894738L; 578 }