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
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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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.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 {@linkplain #equals(Object) equal}
54 * as interchangeable and should not use instances for synchronization, mutexes, or
55 * with {@linkplain java.lang.ref.Reference object references}.
56 *
57 * <div class="preview-block">
58 * <div class="preview-comment">
59 * When preview features are enabled, {@code Short} is a {@linkplain Class#isValue value class}.
60 * Use of value class instances for synchronization, mutexes, or with
61 * {@linkplain java.lang.ref.Reference object references} result in
62 * {@link IdentityException}.
63 * </div>
64 * </div>
65 *
66 * @author Nakul Saraiya
67 * @author Joseph D. Darcy
68 * @see java.lang.Number
69 * @since 1.1
70 */
71 @jdk.internal.MigratedValueClass
72 @jdk.internal.ValueBased
73 public final class Short extends Number implements Comparable<Short>, Constable {
74
75 /**
76 * A constant holding the minimum value a {@code short} can
77 * have, -2<sup>15</sup>.
78 */
79 public static final short MIN_VALUE = -32768;
80
81 /**
82 * A constant holding the maximum value a {@code short} can
83 * have, 2<sup>15</sup>-1.
84 */
85 public static final short MAX_VALUE = 32767;
86
87 /**
88 * The {@code Class} instance representing the primitive type
89 * {@code short}.
90 */
91 public static final Class<Short> TYPE = Class.getPrimitiveClass("short");
92
93 /**
94 * Returns a new {@code String} object representing the
95 * specified {@code short}. The radix is assumed to be 10.
96 *
97 * @param s the {@code short} to be converted
98 * @return the string representation of the specified {@code short}
99 * @see java.lang.Integer#toString(int)
100 */
101 public static String toString(short s) {
102 return Integer.toString(s);
103 }
104
105 /**
106 * Parses the string argument as a signed {@code short} in the
107 * radix specified by the second argument. The characters in the
108 * string must all be digits, of the specified radix (as
109 * determined by whether {@link java.lang.Character#digit(char,
110 * int)} returns a nonnegative value) except that the first
111 * character may be an ASCII minus sign {@code '-'}
112 * ({@code '\u005Cu002D'}) to indicate a negative value or an
113 * ASCII plus sign {@code '+'} ({@code '\u005Cu002B'}) to
114 * indicate a positive value. The resulting {@code short} value
115 * is returned.
116 *
117 * <p>An exception of type {@code NumberFormatException} is
118 * thrown if any of the following situations occurs:
119 * <ul>
120 * <li> The first argument is {@code null} or is a string of
121 * length zero.
122 *
123 * <li> The radix is either smaller than {@link
124 * java.lang.Character#MIN_RADIX} or larger than {@link
125 * java.lang.Character#MAX_RADIX}.
126 *
127 * <li> Any character of the string is not a digit of the
128 * specified radix, except that the first character may be a minus
129 * sign {@code '-'} ({@code '\u005Cu002D'}) or plus sign
130 * {@code '+'} ({@code '\u005Cu002B'}) provided that the
131 * string is longer than length 1.
132 *
133 * <li> The value represented by the string is not a value of type
134 * {@code short}.
135 * </ul>
136 *
137 * @param s the {@code String} containing the
138 * {@code short} representation to be parsed
139 * @param radix the radix to be used while parsing {@code s}
140 * @return the {@code short} represented by the string
141 * argument in the specified radix.
142 * @throws NumberFormatException If the {@code String}
143 * does not contain a parsable {@code short}.
144 */
145 public static short parseShort(String s, int radix)
146 throws NumberFormatException {
147 int i = Integer.parseInt(s, radix);
148 if (i < MIN_VALUE || i > MAX_VALUE)
149 throw new NumberFormatException(
150 "Value out of range. Value:\"" + s + "\" Radix:" + radix);
151 return (short)i;
152 }
153
154 /**
155 * Parses the string argument as a signed decimal {@code
156 * short}. The characters in the string must all be decimal
157 * digits, except that the first character may be an ASCII minus
158 * sign {@code '-'} ({@code '\u005Cu002D'}) to indicate a
159 * negative value or an ASCII plus sign {@code '+'}
160 * ({@code '\u005Cu002B'}) to indicate a positive value. The
161 * resulting {@code short} value is returned, exactly as if the
162 * argument and the radix 10 were given as arguments to the {@link
163 * #parseShort(java.lang.String, int)} method.
164 *
165 * @param s a {@code String} containing the {@code short}
166 * representation to be parsed
167 * @return the {@code short} value represented by the
168 * argument in decimal.
169 * @throws NumberFormatException If the string does not
170 * contain a parsable {@code short}.
171 */
172 public static short parseShort(String s) throws NumberFormatException {
173 return parseShort(s, 10);
174 }
175
176 /**
177 * Returns a {@code Short} object holding the value
178 * extracted from the specified {@code String} when parsed
179 * with the radix given by the second argument. The first argument
180 * is interpreted as representing a signed {@code short} in
181 * the radix specified by the second argument, exactly as if the
182 * argument were given to the {@link #parseShort(java.lang.String,
183 * int)} method. The result is a {@code Short} object that
184 * represents the {@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 Short.valueOf(Short.parseShort(s, radix))}
191 * </blockquote>
192 *
193 * @param s the string to be parsed
194 * @param radix the radix to be used in interpreting {@code s}
195 * @return a {@code Short} object holding the value
196 * represented by the string argument in the
197 * specified radix.
198 * @throws NumberFormatException If the {@code String} does
199 * not contain a parsable {@code short}.
200 */
201 public static Short valueOf(String s, int radix)
202 throws NumberFormatException {
203 return valueOf(parseShort(s, radix));
204 }
205
206 /**
207 * Returns a {@code Short} object holding the
208 * value given by the specified {@code String}. The argument
209 * is interpreted as representing a signed decimal
210 * {@code short}, exactly as if the argument were given to
211 * the {@link #parseShort(java.lang.String)} method. The result is
212 * a {@code Short} object that represents the
213 * {@code short} value specified by the string.
214 *
215 * <p>In other words, this method returns a {@code Short} object
216 * equal to the value of:
217 *
218 * <blockquote>
219 * {@code Short.valueOf(Short.parseShort(s))}
220 * </blockquote>
221 *
222 * @param s the string to be parsed
223 * @return a {@code Short} object holding the value
224 * represented by the string argument
225 * @throws NumberFormatException If the {@code String} does
226 * not contain a parsable {@code short}.
227 */
228 public static Short valueOf(String s) throws NumberFormatException {
229 return valueOf(s, 10);
230 }
231
232 /**
233 * Returns an {@link Optional} containing the nominal descriptor for this
234 * instance.
235 *
236 * @return an {@link Optional} describing the {@linkplain Short} instance
237 * @since 15
238 */
239 @Override
240 public Optional<DynamicConstantDesc<Short>> describeConstable() {
241 return Optional.of(DynamicConstantDesc.ofNamed(BSM_EXPLICIT_CAST, DEFAULT_NAME, CD_short, intValue()));
242 }
243
244 private static final class ShortCache {
245 private ShortCache() {}
246
247 @Stable
248 static final Short[] cache;
249 static Short[] archivedCache;
250
251 static {
252 int size = -(-128) + 127 + 1;
253
254 // Load and use the archived cache if it exists
255 CDS.initializeFromArchive(ShortCache.class);
256 if (archivedCache == null) {
257 Short[] c = new Short[size];
258 short value = -128;
259 for(int i = 0; i < size; i++) {
260 c[i] = new Short(value++);
261 }
262 archivedCache = c;
263 }
264 cache = archivedCache;
265 assert cache.length == size;
266 }
267 }
268
269 /**
270 * Returns a {@code Short} instance representing the specified
271 * {@code short} value.
272 * If a new {@code Short} instance is not required, this method
273 * should generally be used in preference to the constructor
274 * {@link #Short(short)}, as this method is likely to yield
275 * significantly better space and time performance by caching
276 * frequently requested values.
277 *
278 * This method will always cache values in the range -128 to 127,
279 * inclusive, and may cache other values outside of this range.
280 *
281 * @param s a short value.
282 * @return a {@code Short} instance representing {@code s}.
283 * @since 1.5
284 */
285 @IntrinsicCandidate
286 @DeserializeConstructor
287 public static Short valueOf(short s) {
288 final int offset = 128;
289 int sAsInt = s;
290 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
291 return ShortCache.cache[sAsInt + offset];
292 }
293 return new Short(s);
294 }
295
296 /**
297 * Decodes a {@code String} into a {@code Short}.
298 * Accepts decimal, hexadecimal, and octal numbers given by
299 * the following grammar:
300 *
301 * <blockquote>
302 * <dl>
303 * <dt><i>DecodableString:</i>
304 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
305 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
306 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
307 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
308 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
309 *
310 * <dt><i>Sign:</i>
311 * <dd>{@code -}
312 * <dd>{@code +}
313 * </dl>
314 * </blockquote>
315 *
316 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
317 * are as defined in section {@jls 3.10.1} of
318 * <cite>The Java Language Specification</cite>,
319 * except that underscores are not accepted between digits.
320 *
321 * <p>The sequence of characters following an optional
322 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
323 * "{@code #}", or leading zero) is parsed as by the {@code
324 * Short.parseShort} method with the indicated radix (10, 16, or
325 * 8). This sequence of characters must represent a positive
326 * value or a {@link NumberFormatException} will be thrown. The
327 * result is negated if first character of the specified {@code
328 * String} is the minus sign. No whitespace characters are
329 * permitted in the {@code String}.
330 *
331 * @param nm the {@code String} to decode.
332 * @return a {@code Short} object holding the {@code short}
333 * value represented by {@code nm}
334 * @throws NumberFormatException if the {@code String} does not
335 * contain a parsable {@code short}.
336 * @see java.lang.Short#parseShort(java.lang.String, int)
337 */
338 public static Short decode(String nm) throws NumberFormatException {
339 int i = Integer.decode(nm);
340 if (i < MIN_VALUE || i > MAX_VALUE)
341 throw new NumberFormatException(
342 "Value " + i + " out of range from input " + nm);
343 return valueOf((short)i);
344 }
345
346 /**
347 * The value of the {@code Short}.
348 *
349 * @serial
350 */
351 private final short value;
352
353 /**
354 * Constructs a newly allocated {@code Short} object that
355 * represents the specified {@code short} value.
356 *
357 * @param value the value to be represented by the
358 * {@code Short}.
359 *
360 * @deprecated
361 * It is rarely appropriate to use this constructor. The static factory
362 * {@link #valueOf(short)} is generally a better choice, as it is
363 * likely to yield significantly better space and time performance.
364 */
365 @Deprecated(since="9", forRemoval = true)
366 public Short(short value) {
367 this.value = value;
368 }
369
370 /**
371 * Constructs a newly allocated {@code Short} object that
372 * represents the {@code short} value indicated by the
373 * {@code String} parameter. The string is converted to a
374 * {@code short} value in exactly the manner used by the
375 * {@code parseShort} method for radix 10.
376 *
377 * @param s the {@code String} to be converted to a
378 * {@code Short}
379 * @throws NumberFormatException If the {@code String}
380 * does not contain a parsable {@code short}.
381 *
382 * @deprecated
383 * It is rarely appropriate to use this constructor.
384 * Use {@link #parseShort(String)} to convert a string to a
385 * {@code short} primitive, or use {@link #valueOf(String)}
386 * to convert a string to a {@code Short} object.
387 */
388 @Deprecated(since="9", forRemoval = true)
389 public Short(String s) throws NumberFormatException {
390 this.value = parseShort(s, 10);
391 }
392
393 /**
394 * Returns the value of this {@code Short} as a {@code byte} after
395 * a narrowing primitive conversion.
396 * @jls 5.1.3 Narrowing Primitive Conversion
397 */
398 public byte byteValue() {
399 return (byte)value;
400 }
401
402 /**
403 * Returns the value of this {@code Short} as a
404 * {@code short}.
405 */
406 @IntrinsicCandidate
407 public short shortValue() {
408 return value;
409 }
410
411 /**
412 * Returns the value of this {@code Short} as an {@code int} after
413 * a widening primitive conversion.
414 * @jls 5.1.2 Widening Primitive Conversion
415 */
416 public int intValue() {
417 return (int)value;
418 }
419
420 /**
421 * Returns the value of this {@code Short} as a {@code long} after
422 * a widening primitive conversion.
423 * @jls 5.1.2 Widening Primitive Conversion
424 */
425 public long longValue() {
426 return (long)value;
427 }
428
429 /**
430 * Returns the value of this {@code Short} as a {@code float}
431 * after a widening primitive conversion.
432 * @jls 5.1.2 Widening Primitive Conversion
433 */
434 public float floatValue() {
435 return (float)value;
436 }
437
438 /**
439 * Returns the value of this {@code Short} as a {@code double}
440 * after a widening primitive conversion.
441 * @jls 5.1.2 Widening Primitive Conversion
442 */
443 public double doubleValue() {
444 return (double)value;
445 }
446
447 /**
448 * Returns a {@code String} object representing this
449 * {@code Short}'s value. The value is converted to signed
450 * decimal representation and returned as a string, exactly as if
451 * the {@code short} value were given as an argument to the
452 * {@link java.lang.Short#toString(short)} method.
453 *
454 * @return a string representation of the value of this object in
455 * base 10.
456 */
457 @Override
458 public String toString() {
459 return Integer.toString(value);
460 }
461
462 /**
463 * Returns a hash code for this {@code Short}; equal to the result
464 * of invoking {@code intValue()}.
465 *
466 * @return a hash code value for this {@code Short}
467 */
468 @Override
469 public int hashCode() {
470 return Short.hashCode(value);
471 }
472
473 /**
474 * Returns a hash code for a {@code short} value; compatible with
475 * {@code Short.hashCode()}.
476 *
477 * @param value the value to hash
478 * @return a hash code value for a {@code short} value.
479 * @since 1.8
480 */
481 public static int hashCode(short value) {
482 return (int)value;
483 }
484
485 /**
486 * Compares this object to the specified object. The result is
487 * {@code true} if and only if the argument is not
488 * {@code null} and is a {@code Short} object that
489 * contains the same {@code short} value as this object.
490 *
491 * @param obj the object to compare with
492 * @return {@code true} if the objects are the same;
493 * {@code false} otherwise.
494 */
495 public boolean equals(Object obj) {
496 if (obj instanceof Short s) {
497 return value == s.shortValue();
498 }
499 return false;
500 }
501
502 /**
503 * Compares two {@code Short} objects numerically.
504 *
505 * @param anotherShort the {@code Short} to be compared.
506 * @return the value {@code 0} if this {@code Short} is
507 * equal to the argument {@code Short}; a value less than
508 * {@code 0} if this {@code Short} is numerically less
509 * than the argument {@code Short}; and a value greater than
510 * {@code 0} if this {@code Short} is numerically
511 * greater than the argument {@code Short} (signed
512 * comparison).
513 * @since 1.2
514 */
515 public int compareTo(Short anotherShort) {
516 return compare(this.value, anotherShort.value);
517 }
518
519 /**
520 * Compares two {@code short} values numerically.
521 * The value returned is identical to what would be returned by:
522 * <pre>
523 * Short.valueOf(x).compareTo(Short.valueOf(y))
524 * </pre>
525 *
526 * @param x the first {@code short} to compare
527 * @param y the second {@code short} to compare
528 * @return the value {@code 0} if {@code x == y};
529 * a value less than {@code 0} if {@code x < y}; and
530 * a value greater than {@code 0} if {@code x > y}
531 * @since 1.7
532 */
533 public static int compare(short x, short y) {
534 return x - y;
535 }
536
537 /**
538 * Compares two {@code short} values numerically treating the values
539 * as unsigned.
540 *
541 * @param x the first {@code short} to compare
542 * @param y the second {@code short} to compare
543 * @return the value {@code 0} if {@code x == y}; a value less
544 * than {@code 0} if {@code x < y} as unsigned values; and
545 * a value greater than {@code 0} if {@code x > y} as
546 * unsigned values
547 * @since 9
548 */
549 public static int compareUnsigned(short x, short y) {
550 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
551 }
552
553 /**
554 * The number of bits used to represent a {@code short} value in two's
555 * complement binary form.
556 * @since 1.5
557 */
558 public static final int SIZE = 16;
559
560 /**
561 * The number of bytes used to represent a {@code short} value in two's
562 * complement binary form.
563 *
564 * @since 1.8
565 */
566 public static final int BYTES = SIZE / Byte.SIZE;
567
568 /**
569 * Returns the value obtained by reversing the order of the bytes in the
570 * two's complement representation of the specified {@code short} value.
571 *
572 * @param i the value whose bytes are to be reversed
573 * @return the value obtained by reversing (or, equivalently, swapping)
574 * the bytes in the specified {@code short} value.
575 * @since 1.5
576 */
577 @IntrinsicCandidate
578 public static short reverseBytes(short i) {
579 return (short) (((i & 0xFF00) >> 8) | (i << 8));
580 }
581
582
583 /**
584 * Converts the argument to an {@code int} by an unsigned
585 * conversion. In an unsigned conversion to an {@code int}, the
586 * high-order 16 bits of the {@code int} are zero and the
587 * low-order 16 bits are equal to the bits of the {@code short} argument.
588 *
589 * Consequently, zero and positive {@code short} values are mapped
590 * to a numerically equal {@code int} value and negative {@code
591 * short} values are mapped to an {@code int} value equal to the
592 * input plus 2<sup>16</sup>.
593 *
594 * @param x the value to convert to an unsigned {@code int}
595 * @return the argument converted to {@code int} by an unsigned
596 * conversion
597 * @since 1.8
598 */
599 public static int toUnsignedInt(short x) {
600 return ((int) x) & 0xffff;
601 }
602
603 /**
604 * Converts the argument to a {@code long} by an unsigned
605 * conversion. In an unsigned conversion to a {@code long}, the
606 * high-order 48 bits of the {@code long} are zero and the
607 * low-order 16 bits are equal to the bits of the {@code short} argument.
608 *
609 * Consequently, zero and positive {@code short} values are mapped
610 * to a numerically equal {@code long} value and negative {@code
611 * short} values are mapped to a {@code long} value equal to the
612 * input plus 2<sup>16</sup>.
613 *
614 * @param x the value to convert to an unsigned {@code long}
615 * @return the argument converted to {@code long} by an unsigned
616 * conversion
617 * @since 1.8
618 */
619 public static long toUnsignedLong(short x) {
620 return ((long) x) & 0xffffL;
621 }
622
623 /** use serialVersionUID from JDK 1.1. for interoperability */
624 @java.io.Serial
625 private static final long serialVersionUID = 7515723908773894738L;
626 }