1 /* 2 * Copyright 1996-2006 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 new Short(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 * @param s a short value. 223 * @return a {@code Short} instance representing {@code s}. 224 * @since 1.5 225 */ 226 public static Short valueOf(short s) { 227 final int offset = 128; 228 int sAsInt = s; 229 if (sAsInt >= -128 && sAsInt <= 127) { // must cache 230 return ShortCache.cache[sAsInt + offset]; 231 } 232 return new Short(s); 233 } 234 235 /** 236 * Decodes a {@code String} into a {@code Short}. 237 * Accepts decimal, hexadecimal, and octal numbers given by 238 * the following grammar: 239 * 240 * <blockquote> 241 * <dl> 242 * <dt><i>DecodableString:</i> 243 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i> 244 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i> 245 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i> 246 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i> 247 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i> 248 * <p> 249 * <dt><i>Sign:</i> 250 * <dd>{@code -} 251 * <dd>{@code +} 252 * </dl> 253 * </blockquote> 254 * 255 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i> 256 * are defined in <a href="http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html#48282">§3.10.1</a> 257 * of the <a href="http://java.sun.com/docs/books/jls/html/">Java 258 * Language Specification</a>. 259 * 260 * <p>The sequence of characters following an optional 261 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}", 262 * "{@code #}", or leading zero) is parsed as by the {@code 263 * Short.parseShort} method with the indicated radix (10, 16, or 264 * 8). This sequence of characters must represent a positive 265 * value or a {@link NumberFormatException} will be thrown. The 266 * result is negated if first character of the specified {@code 267 * String} is the minus sign. No whitespace characters are 268 * permitted in the {@code String}. 269 * 270 * @param nm the {@code String} to decode. 271 * @return a {@code Short} object holding the {@code short} 272 * value represented by {@code nm} 273 * @throws NumberFormatException if the {@code String} does not 274 * contain a parsable {@code short}. 275 * @see java.lang.Short#parseShort(java.lang.String, int) 276 */ 277 public static Short decode(String nm) throws NumberFormatException { 278 int i = Integer.decode(nm); 279 if (i < MIN_VALUE || i > MAX_VALUE) 280 throw new NumberFormatException( 281 "Value " + i + " out of range from input " + nm); 282 return (short)i; 283 } 284 285 /** 286 * The value of the {@code Short}. 287 * 288 * @serial 289 */ 290 private final short value; 291 292 /** 293 * Constructs a newly allocated {@code Short} object that 294 * represents the specified {@code short} value. 295 * 296 * @param value the value to be represented by the 297 * {@code Short}. 298 */ 299 public Short(short value) { 300 this.value = value; 301 } 302 303 /** 304 * Constructs a newly allocated {@code Short} object that 305 * represents the {@code short} value indicated by the 306 * {@code String} parameter. The string is converted to a 307 * {@code short} value in exactly the manner used by the 308 * {@code parseShort} method for radix 10. 309 * 310 * @param s the {@code String} to be converted to a 311 * {@code Short} 312 * @throws NumberFormatException If the {@code String} 313 * does not contain a parsable {@code short}. 314 * @see java.lang.Short#parseShort(java.lang.String, int) 315 */ 316 public Short(String s) throws NumberFormatException { 317 this.value = parseShort(s, 10); 318 } 319 320 /** 321 * Returns the value of this {@code Short} as a 322 * {@code byte}. 323 */ 324 public byte byteValue() { 325 return (byte)value; 326 } 327 328 /** 329 * Returns the value of this {@code Short} as a 330 * {@code short}. 331 */ 332 public short shortValue() { 333 return value; 334 } 335 336 /** 337 * Returns the value of this {@code Short} as an 338 * {@code int}. 339 */ 340 public int intValue() { 341 return (int)value; 342 } 343 344 /** 345 * Returns the value of this {@code Short} as a 346 * {@code long}. 347 */ 348 public long longValue() { 349 return (long)value; 350 } 351 352 /** 353 * Returns the value of this {@code Short} as a 354 * {@code float}. 355 */ 356 public float floatValue() { 357 return (float)value; 358 } 359 360 /** 361 * Returns the value of this {@code Short} as a 362 * {@code double}. 363 */ 364 public double doubleValue() { 365 return (double)value; 366 } 367 368 /** 369 * Returns a {@code String} object representing this 370 * {@code Short}'s value. The value is converted to signed 371 * decimal representation and returned as a string, exactly as if 372 * the {@code short} value were given as an argument to the 373 * {@link java.lang.Short#toString(short)} method. 374 * 375 * @return a string representation of the value of this object in 376 * base 10. 377 */ 378 public String toString() { 379 return String.valueOf((int)value); 380 } 381 382 /** 383 * Returns a hash code for this {@code Short}. 384 */ 385 public int hashCode() { 386 return (int)value; 387 } 388 389 /** 390 * Compares this object to the specified object. The result is 391 * {@code true} if and only if the argument is not 392 * {@code null} and is a {@code Short} object that 393 * contains the same {@code short} value as this object. 394 * 395 * @param obj the object to compare with 396 * @return {@code true} if the objects are the same; 397 * {@code false} otherwise. 398 */ 399 public boolean equals(Object obj) { 400 if (obj instanceof Short) { 401 return value == ((Short)obj).shortValue(); 402 } 403 return false; 404 } 405 406 /** 407 * Compares two {@code Short} objects numerically. 408 * 409 * @param anotherShort the {@code Short} to be compared. 410 * @return the value {@code 0} if this {@code Short} is 411 * equal to the argument {@code Short}; a value less than 412 * {@code 0} if this {@code Short} is numerically less 413 * than the argument {@code Short}; and a value greater than 414 * {@code 0} if this {@code Short} is numerically 415 * greater than the argument {@code Short} (signed 416 * comparison). 417 * @since 1.2 418 */ 419 public int compareTo(Short anotherShort) { 420 return this.value - anotherShort.value; 421 } 422 423 /** 424 * The number of bits used to represent a {@code short} value in two's 425 * complement binary form. 426 * @since 1.5 427 */ 428 public static final int SIZE = 16; 429 430 /** 431 * Returns the value obtained by reversing the order of the bytes in the 432 * two's complement representation of the specified {@code short} value. 433 * 434 * @return the value obtained by reversing (or, equivalently, swapping) 435 * the bytes in the specified {@code short} value. 436 * @since 1.5 437 */ 438 public static short reverseBytes(short i) { 439 return (short) (((i & 0xFF00) >> 8) | (i << 8)); 440 } 441 442 /** use serialVersionUID from JDK 1.1. for interoperability */ 443 private static final long serialVersionUID = 7515723908773894738L; 444 }