1 /*
2 * Copyright (c) 1996, 2012, 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
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20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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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 '\u005Cu002D'}) to indicate a negative value or an
84 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) 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 '\u005Cu002D'}) or plus sign
101 * {@code '+'} ({@code '\u005Cu002B'}) 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 '\u005Cu002D'}) to indicate a
130 * negative value or an ASCII plus sign {@code '+'}
131 * ({@code '\u005Cu002B'}) 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 {@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 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 * Consequently, zero and positive {@code short} values are mapped
480 * to a numerically equal {@code int} value and negative {@code
481 * short} values are mapped to an {@code int} value equal to the
482 * input plus 2<sup>16</sup>.
483 *
484 * @param x the value to convert to an unsigned {@code int}
485 * @return the argument converted to {@code int} by an unsigned
486 * conversion
487 * @since 1.8
488 */
489 public static int toUnsignedInt(short x) {
490 return ((int) x) & 0xffff;
491 }
492
493 /**
494 * Converts the argument to a {@code long} by an unsigned
495 * conversion. In an unsigned conversion to a {@code long}, the
496 * high-order 48 bits of the {@code long} are zero and the
497 * low-order 16 bits are equal to the bits of the {@code short} argument.
498 *
499 * Consequently, zero and positive {@code short} values are mapped
500 * to a numerically equal {@code long} value and negative {@code
501 * short} values are mapped to a {@code long} value equal to the
502 * input plus 2<sup>16</sup>.
503 *
504 * @param x the value to convert to an unsigned {@code long}
505 * @return the argument converted to {@code long} by an unsigned
506 * conversion
507 * @since 1.8
508 */
509 public static long toUnsignedLong(short x) {
510 return ((long) x) & 0xffffL;
511 }
512
513 /** use serialVersionUID from JDK 1.1. for interoperability */
514 private static final long serialVersionUID = 7515723908773894738L;
515 }