1/* 2 * Copyright (C) 2014 The Android Open Source Project 3 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. Oracle designates this 9 * particular file as subject to the "Classpath" exception as provided 10 * by Oracle in the LICENSE file that accompanied this code. 11 * 12 * This code is distributed in the hope that it will be useful, but WITHOUT 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15 * version 2 for more details (a copy is included in the LICENSE file that 16 * accompanied this code). 17 * 18 * You should have received a copy of the GNU General Public License version 19 * 2 along with this work; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 21 * 22 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 23 * or visit www.oracle.com if you need additional information or have any 24 * questions. 25 */ 26 27package java.lang; 28 29/** 30 * The {@code Short} class wraps a value of primitive type {@code 31 * short} in an object. An object of type {@code Short} contains a 32 * single field whose type is {@code short}. 33 * 34 * <p>In addition, this class provides several methods for converting 35 * a {@code short} to a {@code String} and a {@code String} to a 36 * {@code short}, as well as other constants and methods useful when 37 * dealing with a {@code short}. 38 * 39 * @author Nakul Saraiya 40 * @author Joseph D. Darcy 41 * @see java.lang.Number 42 * @since JDK1.1 43 */ 44public final class Short extends Number implements Comparable<Short> { 45 46 /** 47 * A constant holding the minimum value a {@code short} can 48 * have, -2<sup>15</sup>. 49 */ 50 public static final short MIN_VALUE = -32768; 51 52 /** 53 * A constant holding the maximum value a {@code short} can 54 * have, 2<sup>15</sup>-1. 55 */ 56 public static final short MAX_VALUE = 32767; 57 58 /** 59 * The {@code Class} instance representing the primitive type 60 * {@code short}. 61 */ 62 public static final Class<Short> TYPE = (Class<Short>) short[].class.getComponentType(); 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>'\u002D'</code>) to indicate a negative value or an 84 * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) 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>'\u002D'</code>) or plus sign 101 * {@code '+'} (<code>'\u002B'</code>) 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>'\u002D'</code>) to indicate a 130 * negative value or an ASCII plus sign {@code '+'} 131 * (<code>'\u002B'</code>) 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 326 * {@code byte}. 327 */ 328 public byte byteValue() { 329 return (byte)value; 330 } 331 332 /** 333 * Returns the value of this {@code Short} as a 334 * {@code short}. 335 */ 336 public short shortValue() { 337 return value; 338 } 339 340 /** 341 * Returns the value of this {@code Short} as an 342 * {@code int}. 343 */ 344 public int intValue() { 345 return (int)value; 346 } 347 348 /** 349 * Returns the value of this {@code Short} as a 350 * {@code long}. 351 */ 352 public long longValue() { 353 return (long)value; 354 } 355 356 /** 357 * Returns the value of this {@code Short} as a 358 * {@code float}. 359 */ 360 public float floatValue() { 361 return (float)value; 362 } 363 364 /** 365 * Returns the value of this {@code Short} as a 366 * {@code double}. 367 */ 368 public double doubleValue() { 369 return (double)value; 370 } 371 372 /** 373 * Returns a {@code String} object representing this 374 * {@code Short}'s value. The value is converted to signed 375 * decimal representation and returned as a string, exactly as if 376 * the {@code short} value were given as an argument to the 377 * {@link java.lang.Short#toString(short)} method. 378 * 379 * @return a string representation of the value of this object in 380 * base 10. 381 */ 382 public String toString() { 383 return Integer.toString((int)value); 384 } 385 386 /** 387 * Returns a hash code for this {@code Short}; equal to the result 388 * of invoking {@code intValue()}. 389 * 390 * @return a hash code value for this {@code Short} 391 */ 392 public int hashCode() { 393 return Short.hashCode(value); 394 } 395 396 /** 397 * Returns a hash code for a {@code short} value; compatible with 398 * {@code Short.hashCode()}. 399 * 400 * @param value the value to hash 401 * @return a hash code value for a {@code short} value. 402 * @since 1.8 403 */ 404 public static int hashCode(short value) { 405 return (int)value; 406 } 407 408 /** 409 * Compares this object to the specified object. The result is 410 * {@code true} if and only if the argument is not 411 * {@code null} and is a {@code Short} object that 412 * contains the same {@code short} value as this object. 413 * 414 * @param obj the object to compare with 415 * @return {@code true} if the objects are the same; 416 * {@code false} otherwise. 417 */ 418 public boolean equals(Object obj) { 419 if (obj instanceof Short) { 420 return value == ((Short)obj).shortValue(); 421 } 422 return false; 423 } 424 425 /** 426 * Compares two {@code Short} objects numerically. 427 * 428 * @param anotherShort the {@code Short} to be compared. 429 * @return the value {@code 0} if this {@code Short} is 430 * equal to the argument {@code Short}; a value less than 431 * {@code 0} if this {@code Short} is numerically less 432 * than the argument {@code Short}; and a value greater than 433 * {@code 0} if this {@code Short} is numerically 434 * greater than the argument {@code Short} (signed 435 * comparison). 436 * @since 1.2 437 */ 438 public int compareTo(Short anotherShort) { 439 return compare(this.value, anotherShort.value); 440 } 441 442 /** 443 * Compares two {@code short} values numerically. 444 * The value returned is identical to what would be returned by: 445 * <pre> 446 * Short.valueOf(x).compareTo(Short.valueOf(y)) 447 * </pre> 448 * 449 * @param x the first {@code short} to compare 450 * @param y the second {@code short} to compare 451 * @return the value {@code 0} if {@code x == y}; 452 * a value less than {@code 0} if {@code x < y}; and 453 * a value greater than {@code 0} if {@code x > y} 454 * @since 1.7 455 */ 456 public static int compare(short x, short y) { 457 return x - y; 458 } 459 460 /** 461 * The number of bits used to represent a {@code short} value in two's 462 * complement binary form. 463 * @since 1.5 464 */ 465 public static final int SIZE = 16; 466 467 /** 468 * The number of bytes used to represent a {@code short} value in two's 469 * complement binary form. 470 * 471 * @since 1.8 472 */ 473 public static final int BYTES = SIZE / Byte.SIZE; 474 475 /** 476 * Returns the value obtained by reversing the order of the bytes in the 477 * two's complement representation of the specified {@code short} value. 478 * 479 * @return the value obtained by reversing (or, equivalently, swapping) 480 * the bytes in the specified {@code short} value. 481 * @since 1.5 482 */ 483 public static short reverseBytes(short i) { 484 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 485 } 486 487 /** use serialVersionUID from JDK 1.1. for interoperability */ 488 private static final long serialVersionUID = 7515723908773894738L; 489} 490