1 /*
2 * Copyright (c) 1996, 2019, 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
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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang;
27
28 import jdk.internal.HotSpotIntrinsicCandidate;
29 import jdk.internal.misc.VM;
30
31 /**
32 * The {@code Short} class wraps a value of primitive type {@code
33 * short} in an object. An object of type {@code Short} contains a
34 * single field whose type is {@code short}.
35 *
36 * <p>In addition, this class provides several methods for converting
37 * a {@code short} to a {@code String} and a {@code String} to a
38 * {@code short}, as well as other constants and methods useful when
39 * dealing with a {@code short}.
40 *
41 * @author Nakul Saraiya
42 * @author Joseph D. Darcy
43 * @see java.lang.Number
44 * @since 1.1
45 */
46 public final class Short extends Number implements Comparable<Short> {
47
48 /**
49 * A constant holding the minimum value a {@code short} can
50 * have, -2<sup>15</sup>.
51 */
52 public static final short MIN_VALUE = -32768;
53
54 /**
55 * A constant holding the maximum value a {@code short} can
56 * have, 2<sup>15</sup>-1.
57 */
58 public static final short MAX_VALUE = 32767;
59
60 /**
61 * The {@code Class} instance representing the primitive type
62 * {@code short}.
63 */
64 @SuppressWarnings("unchecked")
65 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short");
66
67 /**
68 * Returns a new {@code String} object representing the
69 * specified {@code short}. The radix is assumed to be 10.
70 *
71 * @param s the {@code short} to be converted
72 * @return the string representation of the specified {@code short}
73 * @see java.lang.Integer#toString(int)
74 */
75 public static String toString(short s) {
76 return Integer.toString((int)s, 10);
77 }
78
79 /**
80 * Parses the string argument as a signed {@code short} in the
81 * radix specified by the second argument. The characters in the
82 * string must all be digits, of the specified radix (as
83 * determined by whether {@link java.lang.Character#digit(char,
84 * int)} returns a nonnegative value) except that the first
85 * character may be an ASCII minus sign {@code '-'}
86 * ({@code '\u005Cu002D'}) to indicate a negative value or an
87 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
88 * indicate a positive value. The resulting {@code short} value
89 * is returned.
90 *
91 * <p>An exception of type {@code NumberFormatException} is
92 * thrown if any of the following situations occurs:
93 * <ul>
94 * <li> The first argument is {@code null} or is a string of
95 * length zero.
96 *
97 * <li> The radix is either smaller than {@link
98 * java.lang.Character#MIN_RADIX} or larger than {@link
99 * java.lang.Character#MAX_RADIX}.
100 *
101 * <li> Any character of the string is not a digit of the
102 * specified radix, except that the first character may be a minus
103 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign
104 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
105 * string is longer than length 1.
106 *
107 * <li> The value represented by the string is not a value of type
108 * {@code short}.
109 * </ul>
110 *
111 * @param s the {@code String} containing the
112 * {@code short} representation to be parsed
113 * @param radix the radix to be used while parsing {@code s}
114 * @return the {@code short} represented by the string
115 * argument in the specified radix.
116 * @throws NumberFormatException If the {@code String}
117 * does not contain a parsable {@code short}.
118 */
119 public static short parseShort(String s, int radix)
120 throws NumberFormatException {
121 int i = Integer.parseInt(s, radix);
122 if (i < MIN_VALUE || i > MAX_VALUE)
123 throw new NumberFormatException(
124 "Value out of range. Value:\"" + s + "\" Radix:" + radix);
125 return (short)i;
126 }
127
128 /**
129 * Parses the string argument as a signed decimal {@code
130 * short}. The characters in the string must all be decimal
131 * digits, except that the first character may be an ASCII minus
132 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
133 * negative value or an ASCII plus sign {@code '+'}
134 * ({@code '\u005Cu002B'}) to indicate a positive value. The
135 * resulting {@code short} value is returned, exactly as if the
136 * argument and the radix 10 were given as arguments to the {@link
137 * #parseShort(java.lang.String, int)} method.
138 *
139 * @param s a {@code String} containing the {@code short}
140 * representation to be parsed
141 * @return the {@code short} value represented by the
142 * argument in decimal.
143 * @throws NumberFormatException If the string does not
144 * contain a parsable {@code short}.
145 */
146 public static short parseShort(String s) throws NumberFormatException {
147 return parseShort(s, 10);
148 }
149
150 /**
151 * Returns a {@code Short} object holding the value
152 * extracted from the specified {@code String} when parsed
153 * with the radix given by the second argument. The first argument
154 * is interpreted as representing a signed {@code short} in
155 * the radix specified by the second argument, exactly as if the
156 * argument were given to the {@link #parseShort(java.lang.String,
157 * int)} method. The result is a {@code Short} object that
158 * represents the {@code short} value specified by the string.
159 *
160 * <p>In other words, this method returns a {@code Short} object
161 * equal to the value of:
162 *
163 * <blockquote>
164 * {@code new Short(Short.parseShort(s, radix))}
165 * </blockquote>
166 *
167 * @param s the string to be parsed
168 * @param radix the radix to be used in interpreting {@code s}
169 * @return a {@code Short} object holding the value
170 * represented by the string argument in the
171 * specified radix.
172 * @throws NumberFormatException If the {@code String} does
173 * not contain a parsable {@code short}.
174 */
175 public static Short valueOf(String s, int radix)
176 throws NumberFormatException {
177 return valueOf(parseShort(s, radix));
178 }
179
180 /**
181 * Returns a {@code Short} object holding the
182 * value given by the specified {@code String}. The argument
183 * is interpreted as representing a signed decimal
184 * {@code short}, exactly as if the argument were given to
185 * the {@link #parseShort(java.lang.String)} method. The result is
186 * a {@code Short} object that represents the
187 * {@code short} value specified by the string.
188 *
189 * <p>In other words, this method returns a {@code Short} object
190 * equal to the value of:
191 *
192 * <blockquote>
193 * {@code new Short(Short.parseShort(s))}
194 * </blockquote>
195 *
196 * @param s the string to be parsed
197 * @return a {@code Short} object holding the value
198 * represented by the string argument
199 * @throws NumberFormatException If the {@code String} does
200 * not contain a parsable {@code short}.
201 */
202 public static Short valueOf(String s) throws NumberFormatException {
203 return valueOf(s, 10);
204 }
205
206 private static class ShortCache {
207 private ShortCache() {}
208
209 static final Short[] cache;
210 static Short[] archivedCache;
211
212 static {
213 int size = -(-128) + 127 + 1;
214
215 // Load and use the archived cache if it exists
216 VM.initializeFromArchive(ShortCache.class);
217 if (archivedCache == null || archivedCache.length != size) {
218 Short[] c = new Short[size];
219 short value = -128;
220 for(int i = 0; i < size; i++) {
221 c[i] = new Short(value++);
222 }
223 archivedCache = c;
224 }
225 cache = archivedCache;
226 }
227 }
228
229 /**
230 * Returns a {@code Short} instance representing the specified
231 * {@code short} value.
232 * If a new {@code Short} instance is not required, this method
233 * should generally be used in preference to the constructor
234 * {@link #Short(short)}, as this method is likely to yield
235 * significantly better space and time performance by caching
236 * frequently requested values.
237 *
238 * This method will always cache values in the range -128 to 127,
239 * inclusive, and may cache other values outside of this range.
240 *
241 * @param s a short value.
242 * @return a {@code Short} instance representing {@code s}.
243 * @since 1.5
244 */
245 @HotSpotIntrinsicCandidate
246 public static Short valueOf(short s) {
247 final int offset = 128;
248 int sAsInt = s;
249 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
250 return ShortCache.cache[sAsInt + offset];
251 }
252 return new Short(s);
253 }
254
255 /**
256 * Decodes a {@code String} into a {@code Short}.
257 * Accepts decimal, hexadecimal, and octal numbers given by
258 * the following grammar:
259 *
260 * <blockquote>
261 * <dl>
262 * <dt><i>DecodableString:</i>
263 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
264 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
265 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
266 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
267 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
268 *
269 * <dt><i>Sign:</i>
270 * <dd>{@code -}
271 * <dd>{@code +}
272 * </dl>
273 * </blockquote>
274 *
275 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
276 * are as defined in section 3.10.1 of
277 * <cite>The Java™ Language Specification</cite>,
278 * except that underscores are not accepted between digits.
279 *
280 * <p>The sequence of characters following an optional
281 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
282 * "{@code #}", or leading zero) is parsed as by the {@code
283 * Short.parseShort} method with the indicated radix (10, 16, or
284 * 8). This sequence of characters must represent a positive
285 * value or a {@link NumberFormatException} will be thrown. The
286 * result is negated if first character of the specified {@code
287 * String} is the minus sign. No whitespace characters are
288 * permitted in the {@code String}.
289 *
290 * @param nm the {@code String} to decode.
291 * @return a {@code Short} object holding the {@code short}
292 * value represented by {@code nm}
293 * @throws NumberFormatException if the {@code String} does not
294 * contain a parsable {@code short}.
295 * @see java.lang.Short#parseShort(java.lang.String, int)
296 */
297 public static Short decode(String nm) throws NumberFormatException {
298 int i = Integer.decode(nm);
299 if (i < MIN_VALUE || i > MAX_VALUE)
300 throw new NumberFormatException(
301 "Value " + i + " out of range from input " + nm);
302 return valueOf((short)i);
303 }
304
305 /**
306 * The value of the {@code Short}.
307 *
308 * @serial
309 */
310 private final short value;
311
312 /**
313 * Constructs a newly allocated {@code Short} object that
314 * represents the specified {@code short} value.
315 *
316 * @param value the value to be represented by the
317 * {@code Short}.
318 *
319 * @deprecated
320 * It is rarely appropriate to use this constructor. The static factory
321 * {@link #valueOf(short)} is generally a better choice, as it is
322 * likely to yield significantly better space and time performance.
323 */
324 @Deprecated(since="9")
325 public Short(short value) {
326 this.value = value;
327 }
328
329 /**
330 * Constructs a newly allocated {@code Short} object that
331 * represents the {@code short} value indicated by the
332 * {@code String} parameter. The string is converted to a
333 * {@code short} value in exactly the manner used by the
334 * {@code parseShort} method for radix 10.
335 *
336 * @param s the {@code String} to be converted to a
337 * {@code Short}
338 * @throws NumberFormatException If the {@code String}
339 * does not contain a parsable {@code short}.
340 *
341 * @deprecated
342 * It is rarely appropriate to use this constructor.
343 * Use {@link #parseShort(String)} to convert a string to a
344 * {@code short} primitive, or use {@link #valueOf(String)}
345 * to convert a string to a {@code Short} object.
346 */
347 @Deprecated(since="9")
348 public Short(String s) throws NumberFormatException {
349 this.value = parseShort(s, 10);
350 }
351
352 /**
353 * Returns the value of this {@code Short} as a {@code byte} after
354 * a narrowing primitive conversion.
355 * @jls 5.1.3 Narrowing Primitive Conversion
356 */
357 public byte byteValue() {
358 return (byte)value;
359 }
360
361 /**
362 * Returns the value of this {@code Short} as a
363 * {@code short}.
364 */
365 @HotSpotIntrinsicCandidate
366 public short shortValue() {
367 return value;
368 }
369
370 /**
371 * Returns the value of this {@code Short} as an {@code int} after
372 * a widening primitive conversion.
373 * @jls 5.1.2 Widening Primitive Conversion
374 */
375 public int intValue() {
376 return (int)value;
377 }
378
379 /**
380 * Returns the value of this {@code Short} as a {@code long} after
381 * a widening primitive conversion.
382 * @jls 5.1.2 Widening Primitive Conversion
383 */
384 public long longValue() {
385 return (long)value;
386 }
387
388 /**
389 * Returns the value of this {@code Short} as a {@code float}
390 * after a widening primitive conversion.
391 * @jls 5.1.2 Widening Primitive Conversion
392 */
393 public float floatValue() {
394 return (float)value;
395 }
396
397 /**
398 * Returns the value of this {@code Short} as a {@code double}
399 * after a widening primitive conversion.
400 * @jls 5.1.2 Widening Primitive Conversion
401 */
402 public double doubleValue() {
403 return (double)value;
404 }
405
406 /**
407 * Returns a {@code String} object representing this
408 * {@code Short}'s value. The value is converted to signed
409 * decimal representation and returned as a string, exactly as if
410 * the {@code short} value were given as an argument to the
411 * {@link java.lang.Short#toString(short)} method.
412 *
413 * @return a string representation of the value of this object in
414 * base 10.
415 */
416 public String toString() {
417 return Integer.toString((int)value);
418 }
419
420 /**
421 * Returns a hash code for this {@code Short}; equal to the result
422 * of invoking {@code intValue()}.
423 *
424 * @return a hash code value for this {@code Short}
425 */
426 @Override
427 public int hashCode() {
428 return Short.hashCode(value);
429 }
430
431 /**
432 * Returns a hash code for a {@code short} value; compatible with
433 * {@code Short.hashCode()}.
434 *
435 * @param value the value to hash
436 * @return a hash code value for a {@code short} value.
437 * @since 1.8
438 */
439 public static int hashCode(short value) {
440 return (int)value;
441 }
442
443 /**
444 * Compares this object to the specified object. The result is
445 * {@code true} if and only if the argument is not
446 * {@code null} and is a {@code Short} object that
447 * contains the same {@code short} value as this object.
448 *
449 * @param obj the object to compare with
450 * @return {@code true} if the objects are the same;
451 * {@code false} otherwise.
452 */
453 public boolean equals(Object obj) {
454 if (obj instanceof Short) {
455 return value == ((Short)obj).shortValue();
456 }
457 return false;
458 }
459
460 /**
461 * Compares two {@code Short} objects numerically.
462 *
463 * @param anotherShort the {@code Short} to be compared.
464 * @return the value {@code 0} if this {@code Short} is
465 * equal to the argument {@code Short}; a value less than
466 * {@code 0} if this {@code Short} is numerically less
467 * than the argument {@code Short}; and a value greater than
468 * {@code 0} if this {@code Short} is numerically
469 * greater than the argument {@code Short} (signed
470 * comparison).
471 * @since 1.2
472 */
473 public int compareTo(Short anotherShort) {
474 return compare(this.value, anotherShort.value);
475 }
476
477 /**
478 * Compares two {@code short} values numerically.
479 * The value returned is identical to what would be returned by:
480 * <pre>
481 * Short.valueOf(x).compareTo(Short.valueOf(y))
482 * </pre>
483 *
484 * @param x the first {@code short} to compare
485 * @param y the second {@code short} to compare
486 * @return the value {@code 0} if {@code x == y};
487 * a value less than {@code 0} if {@code x < y}; and
488 * a value greater than {@code 0} if {@code x > y}
489 * @since 1.7
490 */
491 public static int compare(short x, short y) {
492 return x - y;
493 }
494
495 /**
496 * Compares two {@code short} values numerically treating the values
497 * as unsigned.
498 *
499 * @param x the first {@code short} to compare
500 * @param y the second {@code short} to compare
501 * @return the value {@code 0} if {@code x == y}; a value less
502 * than {@code 0} if {@code x < y} as unsigned values; and
503 * a value greater than {@code 0} if {@code x > y} as
504 * unsigned values
505 * @since 9
506 */
507 public static int compareUnsigned(short x, short y) {
508 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
509 }
510
511 /**
512 * The number of bits used to represent a {@code short} value in two's
513 * complement binary form.
514 * @since 1.5
515 */
516 public static final int SIZE = 16;
517
518 /**
519 * The number of bytes used to represent a {@code short} value in two's
520 * complement binary form.
521 *
522 * @since 1.8
523 */
524 public static final int BYTES = SIZE / Byte.SIZE;
525
526 /**
527 * Returns the value obtained by reversing the order of the bytes in the
528 * two's complement representation of the specified {@code short} value.
529 *
530 * @param i the value whose bytes are to be reversed
531 * @return the value obtained by reversing (or, equivalently, swapping)
532 * the bytes in the specified {@code short} value.
533 * @since 1.5
534 */
535 @HotSpotIntrinsicCandidate
536 public static short reverseBytes(short i) {
537 return (short) (((i & 0xFF00) >> 8) | (i << 8));
538 }
539
540
541 /**
542 * Converts the argument to an {@code int} by an unsigned
543 * conversion. In an unsigned conversion to an {@code int}, the
544 * high-order 16 bits of the {@code int} are zero and the
545 * low-order 16 bits are equal to the bits of the {@code short} argument.
546 *
547 * Consequently, zero and positive {@code short} values are mapped
548 * to a numerically equal {@code int} value and negative {@code
549 * short} values are mapped to an {@code int} value equal to the
550 * input plus 2<sup>16</sup>.
551 *
552 * @param x the value to convert to an unsigned {@code int}
553 * @return the argument converted to {@code int} by an unsigned
554 * conversion
555 * @since 1.8
556 */
557 public static int toUnsignedInt(short x) {
558 return ((int) x) & 0xffff;
559 }
560
561 /**
562 * Converts the argument to a {@code long} by an unsigned
563 * conversion. In an unsigned conversion to a {@code long}, the
564 * high-order 48 bits of the {@code long} are zero and the
565 * low-order 16 bits are equal to the bits of the {@code short} argument.
566 *
567 * Consequently, zero and positive {@code short} values are mapped
568 * to a numerically equal {@code long} value and negative {@code
569 * short} values are mapped to a {@code long} value equal to the
570 * input plus 2<sup>16</sup>.
571 *
572 * @param x the value to convert to an unsigned {@code long}
573 * @return the argument converted to {@code long} by an unsigned
574 * conversion
575 * @since 1.8
576 */
577 public static long toUnsignedLong(short x) {
578 return ((long) x) & 0xffffL;
579 }
580
581 /** use serialVersionUID from JDK 1.1. for interoperability */
582 private static final long serialVersionUID = 7515723908773894738L;
583 }