1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   5  * This code is free software; you can redistribute it and/or modify it
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   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
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  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
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  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>'&#92;u002D'</code>) to indicate a negative value or an
  84      * ASCII plus sign {@code '+'} (<code>'&#92;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>'&#92;u002D'</code>) or plus sign
 101      * {@code '+'} (<code>'&#92;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>'&#92;u002D'</code>) to indicate a
 130      * negative value or an ASCII plus sign {@code '+'}
 131      * (<code>'&#92;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&trade; 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&nbsp;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     public int hashCode() {
 398         return (int)value;
 399     }
 400 
 401     /**
 402      * Compares this object to the specified object.  The result is
 403      * {@code true} if and only if the argument is not
 404      * {@code null} and is a {@code Short} object that
 405      * contains the same {@code short} value as this object.
 406      *
 407      * @param obj       the object to compare with
 408      * @return          {@code true} if the objects are the same;
 409      *                  {@code false} otherwise.
 410      */
 411     public boolean equals(Object obj) {
 412         if (obj instanceof Short) {
 413             return value == ((Short)obj).shortValue();
 414         }
 415         return false;
 416     }
 417 
 418     /**
 419      * Compares two {@code Short} objects numerically.
 420      *
 421      * @param   anotherShort   the {@code Short} to be compared.
 422      * @return  the value {@code 0} if this {@code Short} is
 423      *          equal to the argument {@code Short}; a value less than
 424      *          {@code 0} if this {@code Short} is numerically less
 425      *          than the argument {@code Short}; and a value greater than
 426      *           {@code 0} if this {@code Short} is numerically
 427      *           greater than the argument {@code Short} (signed
 428      *           comparison).
 429      * @since   1.2
 430      */
 431     public int compareTo(Short anotherShort) {
 432         return compare(this.value, anotherShort.value);
 433     }
 434 
 435     /**
 436      * Compares two {@code short} values numerically.
 437      * The value returned is identical to what would be returned by:
 438      * <pre>
 439      *    Short.valueOf(x).compareTo(Short.valueOf(y))
 440      * </pre>
 441      *
 442      * @param  x the first {@code short} to compare
 443      * @param  y the second {@code short} to compare
 444      * @return the value {@code 0} if {@code x == y};
 445      *         a value less than {@code 0} if {@code x < y}; and
 446      *         a value greater than {@code 0} if {@code x > y}
 447      * @since 1.7
 448      */
 449     public static int compare(short x, short y) {
 450         return x - y;
 451     }
 452 
 453     /**
 454      * The number of bits used to represent a {@code short} value in two's
 455      * complement binary form.
 456      * @since 1.5
 457      */
 458     public static final int SIZE = 16;
 459 
 460     /**
 461      * Returns the value obtained by reversing the order of the bytes in the
 462      * two's complement representation of the specified {@code short} value.
 463      *
 464      * @return the value obtained by reversing (or, equivalently, swapping)
 465      *     the bytes in the specified {@code short} value.
 466      * @since 1.5
 467      */
 468     public static short reverseBytes(short i) {
 469         return (short) (((i & 0xFF00) >> 8) | (i << 8));
 470     }
 471 
 472 
 473     /**
 474      * Converts the argument to an {@code int} by an unsigned
 475      * conversion.  In an unsigned conversion to an {@code int}, the
 476      * high-order 16 bits of the {@code int} are zero and the
 477      * low-order 16 bits are equal to the bits of the {@code short} argument.
 478      *
 479      * @return the argument converted to {@code int} by an unsigned
 480      *         conversion
 481      * @param  x the value to convert to an unsigned {@code int}
 482      * @since 1.8
 483      */
 484     public static int toUnsignedInt(short x) {
 485         return ((int) x) & 0xffff;
 486     }
 487 
 488     /**
 489      * Converts the argument to a {@code long} by an unsigned
 490      * conversion.  In an unsigned conversion to a {@code long}, the
 491      * high-order 48 bits of the {@code long} are zero and the
 492      * low-order 16 bits are equal to the bits of the {@code short} argument.
 493      *
 494      * @return the argument converted to {@code long} by an unsigned
 495      *         conversion
 496      * @param  x the value to convert to an unsigned {@code long}
 497      * @since 1.8
 498      */
 499     public static long toUnsignedLong(short x) {
 500         return ((long) x) & 0xffffL;
 501     }
 502 
 503     /** use serialVersionUID from JDK 1.1. for interoperability */
 504     private static final long serialVersionUID = 7515723908773894738L;
 505 }