1 /* 2 * Copyright 1996-2009 Sun Microsystems, Inc. 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. Sun designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 22 * CA 95054 USA or visit www.sun.com if you need additional information or 23 * have any 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 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short"); 62 63 /** 64 * Returns a new {@code String} object representing the 65 * specified {@code short}. The radix is assumed to be 10. 66 * 67 * @param s the {@code short} to be converted 68 * @return the string representation of the specified {@code short} 69 * @see java.lang.Integer#toString(int) 70 */ 71 public static String toString(short s) { 72 return Integer.toString((int)s, 10); 73 } 74 75 /** 76 * Parses the string argument as a signed {@code short} in the 77 * radix specified by the second argument. The characters in the 78 * string must all be digits, of the specified radix (as 79 * determined by whether {@link java.lang.Character#digit(char, 80 * int)} returns a nonnegative value) except that the first 81 * character may be an ASCII minus sign {@code '-'} 82 * (<code>'\u002D'</code>) to indicate a negative value or an 83 * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) to 84 * indicate a positive value. The resulting {@code short} value 85 * is returned. 86 * 87 * <p>An exception of type {@code NumberFormatException} is 88 * thrown if any of the following situations occurs: 89 * <ul> 90 * <li> The first argument is {@code null} or is a string of 91 * length zero. 92 * 93 * <li> The radix is either smaller than {@link 94 * java.lang.Character#MIN_RADIX} or larger than {@link 95 * java.lang.Character#MAX_RADIX}. 96 * 97 * <li> Any character of the string is not a digit of the 98 * specified radix, except that the first character may be a minus 99 * sign {@code '-'} (<code>'\u002D'</code>) or plus sign 100 * {@code '+'} (<code>'\u002B'</code>) provided that the 101 * string is longer than length 1. 102 * 103 * <li> The value represented by the string is not a value of type 104 * {@code short}. 105 * </ul> 106 * 107 * @param s the {@code String} containing the 108 * {@code short} representation to be parsed 109 * @param radix the radix to be used while parsing {@code s} 110 * @return the {@code short} represented by the string 111 * argument in the specified radix. 112 * @throws NumberFormatException If the {@code String} 113 * does not contain a parsable {@code short}. 114 */ 115 public static short parseShort(String s, int radix) 116 throws NumberFormatException { 117 int i = Integer.parseInt(s, radix); 118 if (i < MIN_VALUE || i > MAX_VALUE) 119 throw new NumberFormatException( 120 "Value out of range. Value:\"" + s + "\" Radix:" + radix); 121 return (short)i; 122 } 123 124 /** 125 * Parses the string argument as a signed decimal {@code 126 * short}. The characters in the string must all be decimal 127 * digits, except that the first character may be an ASCII minus 128 * sign {@code '-'} (<code>'\u002D'</code>) to indicate a 129 * negative value or an ASCII plus sign {@code '+'} 130 * (<code>'\u002B'</code>) to indicate a positive value. The 131 * resulting {@code short} value is returned, exactly as if the 132 * argument and the radix 10 were given as arguments to the {@link 133 * #parseShort(java.lang.String, int)} method. 134 * 135 * @param s a {@code String} containing the {@code short} 136 * representation to be parsed 137 * @return the {@code short} value represented by the 138 * argument in decimal. 139 * @throws NumberFormatException If the string does not 140 * contain a parsable {@code short}. 141 */ 142 public static short parseShort(String s) throws NumberFormatException { 143 return parseShort(s, 10); 144 } 145 146 /** 147 * Returns a {@code Short} object holding the value 148 * extracted from the specified {@code String} when parsed 149 * with the radix given by the second argument. The first argument 150 * is interpreted as representing a signed {@code short} in 151 * the radix specified by the second argument, exactly as if the 152 * argument were given to the {@link #parseShort(java.lang.String, 153 * int)} method. The result is a {@code Short} object that 154 * represents the {@code short} value specified by the string. 155 * 156 * <p>In other words, this method returns a {@code Short} object 157 * equal to the value of: 158 * 159 * <blockquote> 160 * {@code new Short(Short.parseShort(s, radix))} 161 * </blockquote> 162 * 163 * @param s the string to be parsed 164 * @param radix the radix to be used in interpreting {@code s} 165 * @return a {@code Short} object holding the value 166 * represented by the string argument in the 167 * specified radix. 168 * @throws NumberFormatException If the {@code String} does 169 * not contain a parsable {@code short}. 170 */ 171 public static Short valueOf(String s, int radix) 172 throws NumberFormatException { 173 return valueOf(parseShort(s, radix)); 174 } 175 176 /** 177 * Returns a {@code Short} object holding the 178 * value given by the specified {@code String}. The argument 179 * is interpreted as representing a signed decimal 180 * {@code short}, exactly as if the argument were given to 181 * the {@link #parseShort(java.lang.String)} method. The result is 182 * a {@code Short} object that represents the 183 * {@code short} value specified by the string. 184 * 185 * <p>In other words, this method returns a {@code Short} object 186 * equal to the value of: 187 * 188 * <blockquote> 189 * {@code new Short(Short.parseShort(s))} 190 * </blockquote> 191 * 192 * @param s the string to be parsed 193 * @return a {@code Short} object holding the value 194 * represented by the string argument 195 * @throws NumberFormatException If the {@code String} does 196 * not contain a parsable {@code short}. 197 */ 198 public static Short valueOf(String s) throws NumberFormatException { 199 return valueOf(s, 10); 200 } 201 202 private static class ShortCache { 203 private ShortCache(){} 204 205 static final Short cache[] = new Short[-(-128) + 127 + 1]; 206 207 static { 208 for(int i = 0; i < cache.length; i++) 209 cache[i] = new Short((short)(i - 128)); 210 } 211 } 212 213 /** 214 * Returns a {@code Short} instance representing the specified 215 * {@code short} value. 216 * If a new {@code Short} instance is not required, this method 217 * should generally be used in preference to the constructor 218 * {@link #Short(short)}, as this method is likely to yield 219 * significantly better space and time performance by caching 220 * frequently requested values. 221 * 222 * This method will always cache values in the range -128 to 127, 223 * inclusive, and may cache other values outside of this range. 224 * 225 * @param s a short value. 226 * @return a {@code Short} instance representing {@code s}. 227 * @since 1.5 228 */ 229 public static Short valueOf(short s) { 230 final int offset = 128; 231 int sAsInt = s; 232 if (sAsInt >= -128 && sAsInt <= 127) { // must cache 233 return ShortCache.cache[sAsInt + offset]; 234 } 235 return new Short(s); 236 } 237 238 /** 239 * Decodes a {@code String} into a {@code Short}. 240 * Accepts decimal, hexadecimal, and octal numbers given by 241 * the following grammar: 242 * 243 * <blockquote> 244 * <dl> 245 * <dt><i>DecodableString:</i> 246 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 247 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 248 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 249 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 250 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 251 * <p> 252 * <dt><i>Sign:</i> 253 * <dd>{@code -} 254 * <dd>{@code +} 255 * </dl> 256 * </blockquote> 257 * 258 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 259 * are defined in <a href="http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html#48282">§3.10.1</a> 260 * of the <a href="http://java.sun.com/docs/books/jls/html/">Java 261 * Language Specification</a>. 262 * 263 * <p>The sequence of characters following an optional 264 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 265 * "{@code #}", or leading zero) is parsed as by the {@code 266 * Short.parseShort} method with the indicated radix (10, 16, or 267 * 8). This sequence of characters must represent a positive 268 * value or a {@link NumberFormatException} will be thrown. The 269 * result is negated if first character of the specified {@code 270 * String} is the minus sign. No whitespace characters are 271 * permitted in the {@code String}. 272 * 273 * @param nm the {@code String} to decode. 274 * @return a {@code Short} object holding the {@code short} 275 * value represented by {@code nm} 276 * @throws NumberFormatException if the {@code String} does not 277 * contain a parsable {@code short}. 278 * @see java.lang.Short#parseShort(java.lang.String, int) 279 */ 280 public static Short decode(String nm) throws NumberFormatException { 281 int i = Integer.decode(nm); 282 if (i < MIN_VALUE || i > MAX_VALUE) 283 throw new NumberFormatException( 284 "Value " + i + " out of range from input " + nm); 285 return valueOf((short)i); 286 } 287 288 /** 289 * The value of the {@code Short}. 290 * 291 * @serial 292 */ 293 private final short value; 294 295 /** 296 * Constructs a newly allocated {@code Short} object that 297 * represents the specified {@code short} value. 298 * 299 * @param value the value to be represented by the 300 * {@code Short}. 301 */ 302 public Short(short value) { 303 this.value = value; 304 } 305 306 /** 307 * Constructs a newly allocated {@code Short} object that 308 * represents the {@code short} value indicated by the 309 * {@code String} parameter. The string is converted to a 310 * {@code short} value in exactly the manner used by the 311 * {@code parseShort} method for radix 10. 312 * 313 * @param s the {@code String} to be converted to a 314 * {@code Short} 315 * @throws NumberFormatException If the {@code String} 316 * does not contain a parsable {@code short}. 317 * @see java.lang.Short#parseShort(java.lang.String, int) 318 */ 319 public Short(String s) throws NumberFormatException { 320 this.value = parseShort(s, 10); 321 } 322 323 /** 324 * Returns the value of this {@code Short} as a 325 * {@code byte}. 326 */ 327 public byte byteValue() { 328 return (byte)value; 329 } 330 331 /** 332 * Returns the value of this {@code Short} as a 333 * {@code short}. 334 */ 335 public short shortValue() { 336 return value; 337 } 338 339 /** 340 * Returns the value of this {@code Short} as an 341 * {@code int}. 342 */ 343 public int intValue() { 344 return (int)value; 345 } 346 347 /** 348 * Returns the value of this {@code Short} as a 349 * {@code long}. 350 */ 351 public long longValue() { 352 return (long)value; 353 } 354 355 /** 356 * Returns the value of this {@code Short} as a 357 * {@code float}. 358 */ 359 public float floatValue() { 360 return (float)value; 361 } 362 363 /** 364 * Returns the value of this {@code Short} as a 365 * {@code double}. 366 */ 367 public double doubleValue() { 368 return (double)value; 369 } 370 371 /** 372 * Returns a {@code String} object representing this 373 * {@code Short}'s value. The value is converted to signed 374 * decimal representation and returned as a string, exactly as if 375 * the {@code short} value were given as an argument to the 376 * {@link java.lang.Short#toString(short)} method. 377 * 378 * @return a string representation of the value of this object in 379 * base 10. 380 */ 381 public String toString() { 382 return Integer.toString((int)value); 383 } 384 385 /** 386 * Returns a hash code for this {@code Short}; equal to the result 387 * of invoking {@code intValue()}. 388 * 389 * @return a hash code value for this {@code Short} 390 */ 391 public int hashCode() { 392 return (int)value; 393 } 394 395 /** 396 * Compares this object to the specified object. The result is 397 * {@code true} if and only if the argument is not 398 * {@code null} and is a {@code Short} object that 399 * contains the same {@code short} value as this object. 400 * 401 * @param obj the object to compare with 402 * @return {@code true} if the objects are the same; 403 * {@code false} otherwise. 404 */ 405 public boolean equals(Object obj) { 406 if (obj instanceof Short) { 407 return value == ((Short)obj).shortValue(); 408 } 409 return false; 410 } 411 412 /** 413 * Compares two {@code Short} objects numerically. 414 * 415 * @param anotherShort the {@code Short} to be compared. 416 * @return the value {@code 0} if this {@code Short} is 417 * equal to the argument {@code Short}; a value less than 418 * {@code 0} if this {@code Short} is numerically less 419 * than the argument {@code Short}; and a value greater than 420 * {@code 0} if this {@code Short} is numerically 421 * greater than the argument {@code Short} (signed 422 * comparison). 423 * @since 1.2 424 */ 425 public int compareTo(Short anotherShort) { 426 return compare(this.value, anotherShort.value); 427 } 428 429 /** 430 * Compares two {@code short} values numerically. 431 * The value returned is identical to what would be returned by: 432 * <pre> 433 * Short.valueOf(x).compareTo(Short.valueOf(y)) 434 * </pre> 435 * 436 * @param x the first {@code short} to compare 437 * @param y the second {@code short} to compare 438 * @return the value {@code 0} if {@code x == y}; 439 * a value less than {@code 0} if {@code x < y}; and 440 * a value greater than {@code 0} if {@code x > y} 441 * @since 1.7 442 */ 443 public static int compare(short x, short y) { 444 return x - y; 445 } 446 447 /** 448 * The number of bits used to represent a {@code short} value in two's 449 * complement binary form. 450 * @since 1.5 451 */ 452 public static final int SIZE = 16; 453 454 /** 455 * Returns the value obtained by reversing the order of the bytes in the 456 * two's complement representation of the specified {@code short} value. 457 * 458 * @return the value obtained by reversing (or, equivalently, swapping) 459 * the bytes in the specified {@code short} value. 460 * @since 1.5 461 */ 462 public static short reverseBytes(short i) { 463 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 464 } 465 466 /** use serialVersionUID from JDK 1.1. for interoperability */ 467 private static final long serialVersionUID = 7515723908773894738L; 468 }