1 /* 2 * Copyright (c) 1996, 2013, 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.HotSpotIntrinsicCandidate; 29 30 /** 31 * The {@code Short} class wraps a value of primitive type {@code 32 * short} in an object. An object of type {@code Short} contains a 33 * single field whose type is {@code short}. 34 * 35 * <p>In addition, this class provides several methods for converting 36 * a {@code short} to a {@code String} and a {@code String} to a 37 * {@code short}, as well as other constants and methods useful when 38 * dealing with a {@code short}. 39 * 40 * @author Nakul Saraiya 41 * @author Joseph D. Darcy 42 * @see java.lang.Number 43 * @since 1.1 44 */ 45 public final class Short extends Number implements Comparable<Short> { 46 47 /** 48 * A constant holding the minimum value a {@code short} can 49 * have, -2<sup>15</sup>. 50 */ 51 public static final short MIN_VALUE = -32768; 52 53 /** 54 * A constant holding the maximum value a {@code short} can 55 * have, 2<sup>15</sup>-1. 56 */ 57 public static final short MAX_VALUE = 32767; 58 59 /** 60 * The {@code Class} instance representing the primitive type 61 * {@code short}. 62 */ 63 @SuppressWarnings("unchecked") 64 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short"); 65 66 /** 67 * Returns a new {@code String} object representing the 68 * specified {@code short}. The radix is assumed to be 10. 69 * 70 * @param s the {@code short} to be converted 71 * @return the string representation of the specified {@code short} 72 * @see java.lang.Integer#toString(int) 73 */ 74 public static String toString(short s) { 75 return Integer.toString((int)s, 10); 76 } 77 78 /** 79 * Parses the string argument as a signed {@code short} in the 80 * radix specified by the second argument. The characters in the 81 * string must all be digits, of the specified radix (as 82 * determined by whether {@link java.lang.Character#digit(char, 83 * int)} returns a nonnegative value) except that the first 84 * character may be an ASCII minus sign {@code '-'} 85 * ({@code '\u005Cu002D'}) to indicate a negative value or an 86 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to 87 * indicate a positive value. The resulting {@code short} value 88 * is returned. 89 * 90 * <p>An exception of type {@code NumberFormatException} is 91 * thrown if any of the following situations occurs: 92 * <ul> 93 * <li> The first argument is {@code null} or is a string of 94 * length zero. 95 * 96 * <li> The radix is either smaller than {@link 97 * java.lang.Character#MIN_RADIX} or larger than {@link 98 * java.lang.Character#MAX_RADIX}. 99 * 100 * <li> Any character of the string is not a digit of the 101 * specified radix, except that the first character may be a minus 102 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign 103 * {@code '+'} ({@code '\u005Cu002B'}) provided that the 104 * string is longer than length 1. 105 * 106 * <li> The value represented by the string is not a value of type 107 * {@code short}. 108 * </ul> 109 * 110 * @param s the {@code String} containing the 111 * {@code short} representation to be parsed 112 * @param radix the radix to be used while parsing {@code s} 113 * @return the {@code short} represented by the string 114 * argument in the specified radix. 115 * @throws NumberFormatException If the {@code String} 116 * does not contain a parsable {@code short}. 117 */ 118 public static short parseShort(String s, int radix) 119 throws NumberFormatException { 120 int i = Integer.parseInt(s, radix); 121 if (i < MIN_VALUE || i > MAX_VALUE) 122 throw new NumberFormatException( 123 "Value out of range. Value:\"" + s + "\" Radix:" + radix); 124 return (short)i; 125 } 126 127 /** 128 * Parses the string argument as a signed decimal {@code 129 * short}. The characters in the string must all be decimal 130 * digits, except that the first character may be an ASCII minus 131 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a 132 * negative value or an ASCII plus sign {@code '+'} 133 * ({@code '\u005Cu002B'}) to indicate a positive value. The 134 * resulting {@code short} value is returned, exactly as if the 135 * argument and the radix 10 were given as arguments to the {@link 136 * #parseShort(java.lang.String, int)} method. 137 * 138 * @param s a {@code String} containing the {@code short} 139 * representation to be parsed 140 * @return the {@code short} value represented by the 141 * argument in decimal. 142 * @throws NumberFormatException If the string does not 143 * contain a parsable {@code short}. 144 */ 145 public static short parseShort(String s) throws NumberFormatException { 146 return parseShort(s, 10); 147 } 148 149 /** 150 * Returns a {@code Short} object holding the value 151 * extracted from the specified {@code String} when parsed 152 * with the radix given by the second argument. The first argument 153 * is interpreted as representing a signed {@code short} in 154 * the radix specified by the second argument, exactly as if the 155 * argument were given to the {@link #parseShort(java.lang.String, 156 * int)} method. The result is a {@code Short} object that 157 * represents the {@code short} value specified by the string. 158 * 159 * <p>In other words, this method returns a {@code Short} object 160 * equal to the value of: 161 * 162 * <blockquote> 163 * {@code new Short(Short.parseShort(s, radix))} 164 * </blockquote> 165 * 166 * @param s the string to be parsed 167 * @param radix the radix to be used in interpreting {@code s} 168 * @return a {@code Short} object holding the value 169 * represented by the string argument in the 170 * specified radix. 171 * @throws NumberFormatException If the {@code String} does 172 * not contain a parsable {@code short}. 173 */ 174 public static Short valueOf(String s, int radix) 175 throws NumberFormatException { 176 return valueOf(parseShort(s, radix)); 177 } 178 179 /** 180 * Returns a {@code Short} object holding the 181 * value given by the specified {@code String}. The argument 182 * is interpreted as representing a signed decimal 183 * {@code short}, exactly as if the argument were given to 184 * the {@link #parseShort(java.lang.String)} method. The result is 185 * a {@code Short} object that represents the 186 * {@code short} value specified by the string. 187 * 188 * <p>In other words, this method returns a {@code Short} object 189 * equal to the value of: 190 * 191 * <blockquote> 192 * {@code new Short(Short.parseShort(s))} 193 * </blockquote> 194 * 195 * @param s the string to be parsed 196 * @return a {@code Short} object holding the value 197 * represented by the string argument 198 * @throws NumberFormatException If the {@code String} does 199 * not contain a parsable {@code short}. 200 */ 201 public static Short valueOf(String s) throws NumberFormatException { 202 return valueOf(s, 10); 203 } 204 205 private static class ShortCache { 206 private ShortCache(){} 207 208 static final Short cache[] = new Short[-(-128) + 127 + 1]; 209 210 static { 211 for(int i = 0; i < cache.length; i++) 212 cache[i] = new Short((short)(i - 128)); 213 } 214 } 215 216 /** 217 * Returns a {@code Short} instance representing the specified 218 * {@code short} value. 219 * If a new {@code Short} instance is not required, this method 220 * should generally be used in preference to the constructor 221 * {@link #Short(short)}, as this method is likely to yield 222 * significantly better space and time performance by caching 223 * frequently requested values. 224 * 225 * This method will always cache values in the range -128 to 127, 226 * inclusive, and may cache other values outside of this range. 227 * 228 * @param s a short value. 229 * @return a {@code Short} instance representing {@code s}. 230 * @since 1.5 231 */ 232 @HotSpotIntrinsicCandidate 233 public static Short valueOf(short s) { 234 final int offset = 128; 235 int sAsInt = s; 236 if (sAsInt >= -128 && sAsInt <= 127) { // must cache 237 return ShortCache.cache[sAsInt + offset]; 238 } 239 return new Short(s); 240 } 241 242 /** 243 * Decodes a {@code String} into a {@code Short}. 244 * Accepts decimal, hexadecimal, and octal numbers given by 245 * the following grammar: 246 * 247 * <blockquote> 248 * <dl> 249 * <dt><i>DecodableString:</i> 250 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 251 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 252 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 253 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 254 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 255 * 256 * <dt><i>Sign:</i> 257 * <dd>{@code -} 258 * <dd>{@code +} 259 * </dl> 260 * </blockquote> 261 * 262 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 263 * are as defined in section 3.10.1 of 264 * <cite>The Java™ Language Specification</cite>, 265 * except that underscores are not accepted between digits. 266 * 267 * <p>The sequence of characters following an optional 268 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 269 * "{@code #}", or leading zero) is parsed as by the {@code 270 * Short.parseShort} method with the indicated radix (10, 16, or 271 * 8). This sequence of characters must represent a positive 272 * value or a {@link NumberFormatException} will be thrown. The 273 * result is negated if first character of the specified {@code 274 * String} is the minus sign. No whitespace characters are 275 * permitted in the {@code String}. 276 * 277 * @param nm the {@code String} to decode. 278 * @return a {@code Short} object holding the {@code short} 279 * value represented by {@code nm} 280 * @throws NumberFormatException if the {@code String} does not 281 * contain a parsable {@code short}. 282 * @see java.lang.Short#parseShort(java.lang.String, int) 283 */ 284 public static Short decode(String nm) throws NumberFormatException { 285 int i = Integer.decode(nm); 286 if (i < MIN_VALUE || i > MAX_VALUE) 287 throw new NumberFormatException( 288 "Value " + i + " out of range from input " + nm); 289 return valueOf((short)i); 290 } 291 292 /** 293 * The value of the {@code Short}. 294 * 295 * @serial 296 */ 297 private final short value; 298 299 /** 300 * Constructs a newly allocated {@code Short} object that 301 * represents the specified {@code short} value. 302 * 303 * @param value the value to be represented by the 304 * {@code Short}. 305 */ 306 public Short(short value) { 307 this.value = value; 308 } 309 310 /** 311 * Constructs a newly allocated {@code Short} object that 312 * represents the {@code short} value indicated by the 313 * {@code String} parameter. The string is converted to a 314 * {@code short} value in exactly the manner used by the 315 * {@code parseShort} method for radix 10. 316 * 317 * @param s the {@code String} to be converted to a 318 * {@code Short} 319 * @throws NumberFormatException If the {@code String} 320 * does not contain a parsable {@code short}. 321 * @see java.lang.Short#parseShort(java.lang.String, int) 322 */ 323 public Short(String s) throws NumberFormatException { 324 this.value = parseShort(s, 10); 325 } 326 327 /** 328 * Returns the value of this {@code Short} as a {@code byte} after 329 * a narrowing primitive conversion. 330 * @jls 5.1.3 Narrowing Primitive Conversions 331 */ 332 public byte byteValue() { 333 return (byte)value; 334 } 335 336 /** 337 * Returns the value of this {@code Short} as a 338 * {@code short}. 339 */ 340 @HotSpotIntrinsicCandidate 341 public short shortValue() { 342 return value; 343 } 344 345 /** 346 * Returns the value of this {@code Short} as an {@code int} after 347 * a widening primitive conversion. 348 * @jls 5.1.2 Widening Primitive Conversions 349 */ 350 public int intValue() { 351 return (int)value; 352 } 353 354 /** 355 * Returns the value of this {@code Short} as a {@code long} after 356 * a widening primitive conversion. 357 * @jls 5.1.2 Widening Primitive Conversions 358 */ 359 public long longValue() { 360 return (long)value; 361 } 362 363 /** 364 * Returns the value of this {@code Short} as a {@code float} 365 * after a widening primitive conversion. 366 * @jls 5.1.2 Widening Primitive Conversions 367 */ 368 public float floatValue() { 369 return (float)value; 370 } 371 372 /** 373 * Returns the value of this {@code Short} as a {@code double} 374 * after a widening primitive conversion. 375 * @jls 5.1.2 Widening Primitive Conversions 376 */ 377 public double doubleValue() { 378 return (double)value; 379 } 380 381 /** 382 * Returns a {@code String} object representing this 383 * {@code Short}'s value. The value is converted to signed 384 * decimal representation and returned as a string, exactly as if 385 * the {@code short} value were given as an argument to the 386 * {@link java.lang.Short#toString(short)} method. 387 * 388 * @return a string representation of the value of this object in 389 * base 10. 390 */ 391 public String toString() { 392 return Integer.toString((int)value); 393 } 394 395 /** 396 * Returns a hash code for this {@code Short}; equal to the result 397 * of invoking {@code intValue()}. 398 * 399 * @return a hash code value for this {@code Short} 400 */ 401 @Override 402 public int hashCode() { 403 return Short.hashCode(value); 404 } 405 406 /** 407 * Returns a hash code for a {@code short} value; compatible with 408 * {@code Short.hashCode()}. 409 * 410 * @param value the value to hash 411 * @return a hash code value for a {@code short} value. 412 * @since 1.8 413 */ 414 public static int hashCode(short value) { 415 return (int)value; 416 } 417 418 /** 419 * Compares this object to the specified object. The result is 420 * {@code true} if and only if the argument is not 421 * {@code null} and is a {@code Short} object that 422 * contains the same {@code short} value as this object. 423 * 424 * @param obj the object to compare with 425 * @return {@code true} if the objects are the same; 426 * {@code false} otherwise. 427 */ 428 public boolean equals(Object obj) { 429 if (obj instanceof Short) { 430 return value == ((Short)obj).shortValue(); 431 } 432 return false; 433 } 434 435 /** 436 * Compares two {@code Short} objects numerically. 437 * 438 * @param anotherShort the {@code Short} to be compared. 439 * @return the value {@code 0} if this {@code Short} is 440 * equal to the argument {@code Short}; a value less than 441 * {@code 0} if this {@code Short} is numerically less 442 * than the argument {@code Short}; and a value greater than 443 * {@code 0} if this {@code Short} is numerically 444 * greater than the argument {@code Short} (signed 445 * comparison). 446 * @since 1.2 447 */ 448 public int compareTo(Short anotherShort) { 449 return compare(this.value, anotherShort.value); 450 } 451 452 /** 453 * Compares two {@code short} values numerically. 454 * The value returned is identical to what would be returned by: 455 * <pre> 456 * Short.valueOf(x).compareTo(Short.valueOf(y)) 457 * </pre> 458 * 459 * @param x the first {@code short} to compare 460 * @param y the second {@code short} to compare 461 * @return the value {@code 0} if {@code x == y}; 462 * a value less than {@code 0} if {@code x < y}; and 463 * a value greater than {@code 0} if {@code x > y} 464 * @since 1.7 465 */ 466 public static int compare(short x, short y) { 467 return x - y; 468 } 469 470 /** 471 * The number of bits used to represent a {@code short} value in two's 472 * complement binary form. 473 * @since 1.5 474 */ 475 public static final int SIZE = 16; 476 477 /** 478 * The number of bytes used to represent a {@code short} value in two's 479 * complement binary form. 480 * 481 * @since 1.8 482 */ 483 public static final int BYTES = SIZE / Byte.SIZE; 484 485 /** 486 * Returns the value obtained by reversing the order of the bytes in the 487 * two's complement representation of the specified {@code short} value. 488 * 489 * @param i the value whose bytes are to be reversed 490 * @return the value obtained by reversing (or, equivalently, swapping) 491 * the bytes in the specified {@code short} value. 492 * @since 1.5 493 */ 494 @HotSpotIntrinsicCandidate 495 public static short reverseBytes(short i) { 496 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 497 } 498 499 500 /** 501 * Converts the argument to an {@code int} by an unsigned 502 * conversion. In an unsigned conversion to an {@code int}, the 503 * high-order 16 bits of the {@code int} are zero and the 504 * low-order 16 bits are equal to the bits of the {@code short} argument. 505 * 506 * Consequently, zero and positive {@code short} values are mapped 507 * to a numerically equal {@code int} value and negative {@code 508 * short} values are mapped to an {@code int} value equal to the 509 * input plus 2<sup>16</sup>. 510 * 511 * @param x the value to convert to an unsigned {@code int} 512 * @return the argument converted to {@code int} by an unsigned 513 * conversion 514 * @since 1.8 515 */ 516 public static int toUnsignedInt(short x) { 517 return ((int) x) & 0xffff; 518 } 519 520 /** 521 * Converts the argument to a {@code long} by an unsigned 522 * conversion. In an unsigned conversion to a {@code long}, the 523 * high-order 48 bits of the {@code long} are zero and the 524 * low-order 16 bits are equal to the bits of the {@code short} argument. 525 * 526 * Consequently, zero and positive {@code short} values are mapped 527 * to a numerically equal {@code long} value and negative {@code 528 * short} values are mapped to a {@code long} value equal to the 529 * input plus 2<sup>16</sup>. 530 * 531 * @param x the value to convert to an unsigned {@code long} 532 * @return the argument converted to {@code long} by an unsigned 533 * conversion 534 * @since 1.8 535 */ 536 public static long toUnsignedLong(short x) { 537 return ((long) x) & 0xffffL; 538 } 539 540 /** use serialVersionUID from JDK 1.1. for interoperability */ 541 private static final long serialVersionUID = 7515723908773894738L; 542 }