1 /*
2 * Copyright (c) 1996, 2024, 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
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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 *
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20 *
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24 */
25
26 package java.lang;
27
28 import jdk.internal.misc.CDS;
29 import jdk.internal.value.DeserializeConstructor;
30 import jdk.internal.vm.annotation.IntrinsicCandidate;
31 import jdk.internal.vm.annotation.Stable;
32
33 import java.lang.constant.Constable;
34 import java.lang.constant.DynamicConstantDesc;
35 import java.util.Optional;
36
37 import static java.lang.constant.ConstantDescs.BSM_EXPLICIT_CAST;
38 import static java.lang.constant.ConstantDescs.CD_short;
39 import static java.lang.constant.ConstantDescs.DEFAULT_NAME;
40
41 /**
42 * The {@code Short} class is the {@linkplain
43 * java.lang##wrapperClass wrapper class} for values of the primitive
44 * type {@code short}. An object of type {@code Short} contains a
45 * single field whose type is {@code short}.
46 *
47 * <p>In addition, this class provides several methods for converting
48 * a {@code short} to a {@code String} and a {@code String} to a
49 * {@code short}, as well as other constants and methods useful when
50 * dealing with a {@code short}.
51 *
52 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
53 * class; programmers should treat instances that are
54 * {@linkplain #equals(Object) equal} as interchangeable and should not
55 * use instances for synchronization, or unpredictable behavior may
56 * occur. For example, in a future release, synchronization may fail.
57 *
58 * @author Nakul Saraiya
59 * @author Joseph D. Darcy
60 * @see java.lang.Number
61 * @since 1.1
62 */
63 @jdk.internal.MigratedValueClass
64 @jdk.internal.ValueBased
65 public final class Short extends Number implements Comparable<Short>, Constable {
66
67 /**
68 * A constant holding the minimum value a {@code short} can
69 * have, -2<sup>15</sup>.
70 */
71 public static final short MIN_VALUE = -32768;
72
73 /**
74 * A constant holding the maximum value a {@code short} can
75 * have, 2<sup>15</sup>-1.
76 */
77 public static final short MAX_VALUE = 32767;
78
79 /**
80 * The {@code Class} instance representing the primitive type
81 * {@code short}.
82 */
83 public static final Class<Short> TYPE = Class.getPrimitiveClass("short");
84
85 /**
86 * Returns a new {@code String} object representing the
87 * specified {@code short}. The radix is assumed to be 10.
88 *
89 * @param s the {@code short} to be converted
90 * @return the string representation of the specified {@code short}
91 * @see java.lang.Integer#toString(int)
92 */
93 public static String toString(short s) {
94 return Integer.toString(s);
95 }
96
97 /**
98 * Parses the string argument as a signed {@code short} in the
99 * radix specified by the second argument. The characters in the
100 * string must all be digits, of the specified radix (as
101 * determined by whether {@link java.lang.Character#digit(char,
102 * int)} returns a nonnegative value) except that the first
103 * character may be an ASCII minus sign {@code '-'}
104 * ({@code '\u005Cu002D'}) to indicate a negative value or an
105 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
106 * indicate a positive value. The resulting {@code short} value
107 * is returned.
108 *
109 * <p>An exception of type {@code NumberFormatException} is
110 * thrown if any of the following situations occurs:
111 * <ul>
112 * <li> The first argument is {@code null} or is a string of
113 * length zero.
114 *
115 * <li> The radix is either smaller than {@link
116 * java.lang.Character#MIN_RADIX} or larger than {@link
117 * java.lang.Character#MAX_RADIX}.
118 *
119 * <li> Any character of the string is not a digit of the
120 * specified radix, except that the first character may be a minus
121 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign
122 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
123 * string is longer than length 1.
124 *
125 * <li> The value represented by the string is not a value of type
126 * {@code short}.
127 * </ul>
128 *
129 * @param s the {@code String} containing the
130 * {@code short} representation to be parsed
131 * @param radix the radix to be used while parsing {@code s}
132 * @return the {@code short} represented by the string
133 * argument in the specified radix.
134 * @throws NumberFormatException If the {@code String}
135 * does not contain a parsable {@code short}.
136 */
137 public static short parseShort(String s, int radix)
138 throws NumberFormatException {
139 int i = Integer.parseInt(s, radix);
140 if (i < MIN_VALUE || i > MAX_VALUE)
141 throw new NumberFormatException(
142 "Value out of range. Value:\"" + s + "\" Radix:" + radix);
143 return (short)i;
144 }
145
146 /**
147 * Parses the string argument as a signed decimal {@code
148 * short}. The characters in the string must all be decimal
149 * digits, except that the first character may be an ASCII minus
150 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
151 * negative value or an ASCII plus sign {@code '+'}
152 * ({@code '\u005Cu002B'}) to indicate a positive value. The
153 * resulting {@code short} value is returned, exactly as if the
154 * argument and the radix 10 were given as arguments to the {@link
155 * #parseShort(java.lang.String, int)} method.
156 *
157 * @param s a {@code String} containing the {@code short}
158 * representation to be parsed
159 * @return the {@code short} value represented by the
160 * argument in decimal.
161 * @throws NumberFormatException If the string does not
162 * contain a parsable {@code short}.
163 */
164 public static short parseShort(String s) throws NumberFormatException {
165 return parseShort(s, 10);
166 }
167
168 /**
169 * Returns a {@code Short} object holding the value
170 * extracted from the specified {@code String} when parsed
171 * with the radix given by the second argument. The first argument
172 * is interpreted as representing a signed {@code short} in
173 * the radix specified by the second argument, exactly as if the
174 * argument were given to the {@link #parseShort(java.lang.String,
175 * int)} method. The result is a {@code Short} object that
176 * represents the {@code short} value specified by the string.
177 *
178 * <p>In other words, this method returns a {@code Short} object
179 * equal to the value of:
180 *
181 * <blockquote>
182 * {@code Short.valueOf(Short.parseShort(s, radix))}
183 * </blockquote>
184 *
185 * @param s the string to be parsed
186 * @param radix the radix to be used in interpreting {@code s}
187 * @return a {@code Short} object holding the value
188 * represented by the string argument in the
189 * specified radix.
190 * @throws NumberFormatException If the {@code String} does
191 * not contain a parsable {@code short}.
192 */
193 public static Short valueOf(String s, int radix)
194 throws NumberFormatException {
195 return valueOf(parseShort(s, radix));
196 }
197
198 /**
199 * Returns a {@code Short} object holding the
200 * value given by the specified {@code String}. The argument
201 * is interpreted as representing a signed decimal
202 * {@code short}, exactly as if the argument were given to
203 * the {@link #parseShort(java.lang.String)} method. The result is
204 * a {@code Short} object that represents the
205 * {@code short} value specified by the string.
206 *
207 * <p>In other words, this method returns a {@code Short} object
208 * equal to the value of:
209 *
210 * <blockquote>
211 * {@code Short.valueOf(Short.parseShort(s))}
212 * </blockquote>
213 *
214 * @param s the string to be parsed
215 * @return a {@code Short} object holding the value
216 * represented by the string argument
217 * @throws NumberFormatException If the {@code String} does
218 * not contain a parsable {@code short}.
219 */
220 public static Short valueOf(String s) throws NumberFormatException {
221 return valueOf(s, 10);
222 }
223
224 /**
225 * Returns an {@link Optional} containing the nominal descriptor for this
226 * instance.
227 *
228 * @return an {@link Optional} describing the {@linkplain Short} instance
229 * @since 15
230 */
231 @Override
232 public Optional<DynamicConstantDesc<Short>> describeConstable() {
233 return Optional.of(DynamicConstantDesc.ofNamed(BSM_EXPLICIT_CAST, DEFAULT_NAME, CD_short, intValue()));
234 }
235
236 private static final class ShortCache {
237 private ShortCache() {}
238
239 @Stable
240 static final Short[] cache;
241 static Short[] archivedCache;
242
243 static {
244 int size = -(-128) + 127 + 1;
245
246 // Load and use the archived cache if it exists
247 CDS.initializeFromArchive(ShortCache.class);
248 if (archivedCache == null) {
249 Short[] c = new Short[size];
250 short value = -128;
251 for(int i = 0; i < size; i++) {
252 c[i] = new Short(value++);
253 }
254 archivedCache = c;
255 }
256 cache = archivedCache;
257 assert cache.length == size;
258 }
259 }
260
261 /**
262 * Returns a {@code Short} instance representing the specified
263 * {@code short} value.
264 * If a new {@code Short} instance is not required, this method
265 * should generally be used in preference to the constructor
266 * {@link #Short(short)}, as this method is likely to yield
267 * significantly better space and time performance by caching
268 * frequently requested values.
269 *
270 * This method will always cache values in the range -128 to 127,
271 * inclusive, and may cache other values outside of this range.
272 *
273 * @param s a short value.
274 * @return a {@code Short} instance representing {@code s}.
275 * @since 1.5
276 */
277 @IntrinsicCandidate
278 @DeserializeConstructor
279 public static Short valueOf(short s) {
280 final int offset = 128;
281 int sAsInt = s;
282 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
283 return ShortCache.cache[sAsInt + offset];
284 }
285 return new Short(s);
286 }
287
288 /**
289 * Decodes a {@code String} into a {@code Short}.
290 * Accepts decimal, hexadecimal, and octal numbers given by
291 * the following grammar:
292 *
293 * <blockquote>
294 * <dl>
295 * <dt><i>DecodableString:</i>
296 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
297 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
298 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
299 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
300 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
301 *
302 * <dt><i>Sign:</i>
303 * <dd>{@code -}
304 * <dd>{@code +}
305 * </dl>
306 * </blockquote>
307 *
308 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
309 * are as defined in section {@jls 3.10.1} of
310 * <cite>The Java Language Specification</cite>,
311 * except that underscores are not accepted between digits.
312 *
313 * <p>The sequence of characters following an optional
314 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
315 * "{@code #}", or leading zero) is parsed as by the {@code
316 * Short.parseShort} method with the indicated radix (10, 16, or
317 * 8). This sequence of characters must represent a positive
318 * value or a {@link NumberFormatException} will be thrown. The
319 * result is negated if first character of the specified {@code
320 * String} is the minus sign. No whitespace characters are
321 * permitted in the {@code String}.
322 *
323 * @param nm the {@code String} to decode.
324 * @return a {@code Short} object holding the {@code short}
325 * value represented by {@code nm}
326 * @throws NumberFormatException if the {@code String} does not
327 * contain a parsable {@code short}.
328 * @see java.lang.Short#parseShort(java.lang.String, int)
329 */
330 public static Short decode(String nm) throws NumberFormatException {
331 int i = Integer.decode(nm);
332 if (i < MIN_VALUE || i > MAX_VALUE)
333 throw new NumberFormatException(
334 "Value " + i + " out of range from input " + nm);
335 return valueOf((short)i);
336 }
337
338 /**
339 * The value of the {@code Short}.
340 *
341 * @serial
342 */
343 private final short value;
344
345 /**
346 * Constructs a newly allocated {@code Short} object that
347 * represents the specified {@code short} value.
348 *
349 * @param value the value to be represented by the
350 * {@code Short}.
351 *
352 * @deprecated
353 * It is rarely appropriate to use this constructor. The static factory
354 * {@link #valueOf(short)} is generally a better choice, as it is
355 * likely to yield significantly better space and time performance.
356 */
357 @Deprecated(since="9", forRemoval = true)
358 public Short(short value) {
359 this.value = value;
360 }
361
362 /**
363 * Constructs a newly allocated {@code Short} object that
364 * represents the {@code short} value indicated by the
365 * {@code String} parameter. The string is converted to a
366 * {@code short} value in exactly the manner used by the
367 * {@code parseShort} method for radix 10.
368 *
369 * @param s the {@code String} to be converted to a
370 * {@code Short}
371 * @throws NumberFormatException If the {@code String}
372 * does not contain a parsable {@code short}.
373 *
374 * @deprecated
375 * It is rarely appropriate to use this constructor.
376 * Use {@link #parseShort(String)} to convert a string to a
377 * {@code short} primitive, or use {@link #valueOf(String)}
378 * to convert a string to a {@code Short} object.
379 */
380 @Deprecated(since="9", forRemoval = true)
381 public Short(String s) throws NumberFormatException {
382 this.value = parseShort(s, 10);
383 }
384
385 /**
386 * Returns the value of this {@code Short} as a {@code byte} after
387 * a narrowing primitive conversion.
388 * @jls 5.1.3 Narrowing Primitive Conversion
389 */
390 public byte byteValue() {
391 return (byte)value;
392 }
393
394 /**
395 * Returns the value of this {@code Short} as a
396 * {@code short}.
397 */
398 @IntrinsicCandidate
399 public short shortValue() {
400 return value;
401 }
402
403 /**
404 * Returns the value of this {@code Short} as an {@code int} after
405 * a widening primitive conversion.
406 * @jls 5.1.2 Widening Primitive Conversion
407 */
408 public int intValue() {
409 return (int)value;
410 }
411
412 /**
413 * Returns the value of this {@code Short} as a {@code long} after
414 * a widening primitive conversion.
415 * @jls 5.1.2 Widening Primitive Conversion
416 */
417 public long longValue() {
418 return (long)value;
419 }
420
421 /**
422 * Returns the value of this {@code Short} as a {@code float}
423 * after a widening primitive conversion.
424 * @jls 5.1.2 Widening Primitive Conversion
425 */
426 public float floatValue() {
427 return (float)value;
428 }
429
430 /**
431 * Returns the value of this {@code Short} as a {@code double}
432 * after a widening primitive conversion.
433 * @jls 5.1.2 Widening Primitive Conversion
434 */
435 public double doubleValue() {
436 return (double)value;
437 }
438
439 /**
440 * Returns a {@code String} object representing this
441 * {@code Short}'s value. The value is converted to signed
442 * decimal representation and returned as a string, exactly as if
443 * the {@code short} value were given as an argument to the
444 * {@link java.lang.Short#toString(short)} method.
445 *
446 * @return a string representation of the value of this object in
447 * base 10.
448 */
449 @Override
450 public String toString() {
451 return Integer.toString(value);
452 }
453
454 /**
455 * Returns a hash code for this {@code Short}; equal to the result
456 * of invoking {@code intValue()}.
457 *
458 * @return a hash code value for this {@code Short}
459 */
460 @Override
461 public int hashCode() {
462 return Short.hashCode(value);
463 }
464
465 /**
466 * Returns a hash code for a {@code short} value; compatible with
467 * {@code Short.hashCode()}.
468 *
469 * @param value the value to hash
470 * @return a hash code value for a {@code short} value.
471 * @since 1.8
472 */
473 public static int hashCode(short value) {
474 return (int)value;
475 }
476
477 /**
478 * Compares this object to the specified object. The result is
479 * {@code true} if and only if the argument is not
480 * {@code null} and is a {@code Short} object that
481 * contains the same {@code short} value as this object.
482 *
483 * @param obj the object to compare with
484 * @return {@code true} if the objects are the same;
485 * {@code false} otherwise.
486 */
487 public boolean equals(Object obj) {
488 if (obj instanceof Short s) {
489 return value == s.shortValue();
490 }
491 return false;
492 }
493
494 /**
495 * Compares two {@code Short} objects numerically.
496 *
497 * @param anotherShort the {@code Short} to be compared.
498 * @return the value {@code 0} if this {@code Short} is
499 * equal to the argument {@code Short}; a value less than
500 * {@code 0} if this {@code Short} is numerically less
501 * than the argument {@code Short}; and a value greater than
502 * {@code 0} if this {@code Short} is numerically
503 * greater than the argument {@code Short} (signed
504 * comparison).
505 * @since 1.2
506 */
507 public int compareTo(Short anotherShort) {
508 return compare(this.value, anotherShort.value);
509 }
510
511 /**
512 * Compares two {@code short} values numerically.
513 * The value returned is identical to what would be returned by:
514 * <pre>
515 * Short.valueOf(x).compareTo(Short.valueOf(y))
516 * </pre>
517 *
518 * @param x the first {@code short} to compare
519 * @param y the second {@code short} to compare
520 * @return the value {@code 0} if {@code x == y};
521 * a value less than {@code 0} if {@code x < y}; and
522 * a value greater than {@code 0} if {@code x > y}
523 * @since 1.7
524 */
525 public static int compare(short x, short y) {
526 return x - y;
527 }
528
529 /**
530 * Compares two {@code short} values numerically treating the values
531 * as unsigned.
532 *
533 * @param x the first {@code short} to compare
534 * @param y the second {@code short} to compare
535 * @return the value {@code 0} if {@code x == y}; a value less
536 * than {@code 0} if {@code x < y} as unsigned values; and
537 * a value greater than {@code 0} if {@code x > y} as
538 * unsigned values
539 * @since 9
540 */
541 public static int compareUnsigned(short x, short y) {
542 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
543 }
544
545 /**
546 * The number of bits used to represent a {@code short} value in two's
547 * complement binary form.
548 * @since 1.5
549 */
550 public static final int SIZE = 16;
551
552 /**
553 * The number of bytes used to represent a {@code short} value in two's
554 * complement binary form.
555 *
556 * @since 1.8
557 */
558 public static final int BYTES = SIZE / Byte.SIZE;
559
560 /**
561 * Returns the value obtained by reversing the order of the bytes in the
562 * two's complement representation of the specified {@code short} value.
563 *
564 * @param i the value whose bytes are to be reversed
565 * @return the value obtained by reversing (or, equivalently, swapping)
566 * the bytes in the specified {@code short} value.
567 * @since 1.5
568 */
569 @IntrinsicCandidate
570 public static short reverseBytes(short i) {
571 return (short) (((i & 0xFF00) >> 8) | (i << 8));
572 }
573
574
575 /**
576 * Converts the argument to an {@code int} by an unsigned
577 * conversion. In an unsigned conversion to an {@code int}, the
578 * high-order 16 bits of the {@code int} are zero and the
579 * low-order 16 bits are equal to the bits of the {@code short} argument.
580 *
581 * Consequently, zero and positive {@code short} values are mapped
582 * to a numerically equal {@code int} value and negative {@code
583 * short} values are mapped to an {@code int} value equal to the
584 * input plus 2<sup>16</sup>.
585 *
586 * @param x the value to convert to an unsigned {@code int}
587 * @return the argument converted to {@code int} by an unsigned
588 * conversion
589 * @since 1.8
590 */
591 public static int toUnsignedInt(short x) {
592 return ((int) x) & 0xffff;
593 }
594
595 /**
596 * Converts the argument to a {@code long} by an unsigned
597 * conversion. In an unsigned conversion to a {@code long}, the
598 * high-order 48 bits of the {@code long} are zero and the
599 * low-order 16 bits are equal to the bits of the {@code short} argument.
600 *
601 * Consequently, zero and positive {@code short} values are mapped
602 * to a numerically equal {@code long} value and negative {@code
603 * short} values are mapped to a {@code long} value equal to the
604 * input plus 2<sup>16</sup>.
605 *
606 * @param x the value to convert to an unsigned {@code long}
607 * @return the argument converted to {@code long} by an unsigned
608 * conversion
609 * @since 1.8
610 */
611 public static long toUnsignedLong(short x) {
612 return ((long) x) & 0xffffL;
613 }
614
615 /** use serialVersionUID from JDK 1.1. for interoperability */
616 @java.io.Serial
617 private static final long serialVersionUID = 7515723908773894738L;
618 }