1 /*
2 * Copyright (c) 1996, 2023, 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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10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
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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).
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24 */
25
26 package java.lang;
27
28 import jdk.internal.misc.CDS;
29 import jdk.internal.vm.annotation.IntrinsicCandidate;
30 import jdk.internal.vm.annotation.Stable;
31
32 import java.lang.constant.Constable;
33 import java.lang.constant.DynamicConstantDesc;
34 import java.util.Optional;
35
36 import static java.lang.constant.ConstantDescs.BSM_EXPLICIT_CAST;
37 import static java.lang.constant.ConstantDescs.CD_int;
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 wraps a value of primitive type {@code
43 * short} in an object. An object of type {@code Short} contains a
44 * single field whose type is {@code short}.
45 *
46 * <p>In addition, this class provides several methods for converting
47 * a {@code short} to a {@code String} and a {@code String} to a
48 * {@code short}, as well as other constants and methods useful when
49 * dealing with a {@code short}.
50 *
51 * <p>This is a <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>
52 * class; programmers should treat instances that are
53 * {@linkplain #equals(Object) equal} as interchangeable and should not
54 * use instances for synchronization, or unpredictable behavior may
55 * occur. For example, in a future release, synchronization may fail.
56 *
57 * @author Nakul Saraiya
58 * @author Joseph D. Darcy
59 * @see java.lang.Number
60 * @since 1.1
61 */
62 @jdk.internal.MigratedValueClass
63 @jdk.internal.ValueBased
64 public final class Short extends Number implements Comparable<Short>, Constable {
65
66 /**
67 * A constant holding the minimum value a {@code short} can
68 * have, -2<sup>15</sup>.
69 */
70 public static final short MIN_VALUE = -32768;
71
72 /**
73 * A constant holding the maximum value a {@code short} can
74 * have, 2<sup>15</sup>-1.
75 */
76 public static final short MAX_VALUE = 32767;
77
78 /**
79 * The {@code Class} instance representing the primitive type
80 * {@code short}.
81 */
82 @SuppressWarnings("unchecked")
83 public static final Class<Short> TYPE = (Class<Short>) 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 || archivedCache.length != size) {
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 }
258 }
259
260 /**
261 * Returns a {@code Short} instance representing the specified
262 * {@code short} value.
263 * If a new {@code Short} instance is not required, this method
264 * should generally be used in preference to the constructor
265 * {@link #Short(short)}, as this method is likely to yield
266 * significantly better space and time performance by caching
267 * frequently requested values.
268 *
269 * This method will always cache values in the range -128 to 127,
270 * inclusive, and may cache other values outside of this range.
271 *
272 * @param s a short value.
273 * @return a {@code Short} instance representing {@code s}.
274 * @since 1.5
275 */
276 @IntrinsicCandidate
277 public static Short valueOf(short s) {
278 final int offset = 128;
279 int sAsInt = s;
280 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
281 return ShortCache.cache[sAsInt + offset];
282 }
283 return new Short(s);
284 }
285
286 /**
287 * Decodes a {@code String} into a {@code Short}.
288 * Accepts decimal, hexadecimal, and octal numbers given by
289 * the following grammar:
290 *
291 * <blockquote>
292 * <dl>
293 * <dt><i>DecodableString:</i>
294 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
295 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
296 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
297 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
298 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
299 *
300 * <dt><i>Sign:</i>
301 * <dd>{@code -}
302 * <dd>{@code +}
303 * </dl>
304 * </blockquote>
305 *
306 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
307 * are as defined in section {@jls 3.10.1} of
308 * <cite>The Java Language Specification</cite>,
309 * except that underscores are not accepted between digits.
310 *
311 * <p>The sequence of characters following an optional
312 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
313 * "{@code #}", or leading zero) is parsed as by the {@code
314 * Short.parseShort} method with the indicated radix (10, 16, or
315 * 8). This sequence of characters must represent a positive
316 * value or a {@link NumberFormatException} will be thrown. The
317 * result is negated if first character of the specified {@code
318 * String} is the minus sign. No whitespace characters are
319 * permitted in the {@code String}.
320 *
321 * @param nm the {@code String} to decode.
322 * @return a {@code Short} object holding the {@code short}
323 * value represented by {@code nm}
324 * @throws NumberFormatException if the {@code String} does not
325 * contain a parsable {@code short}.
326 * @see java.lang.Short#parseShort(java.lang.String, int)
327 */
328 public static Short decode(String nm) throws NumberFormatException {
329 int i = Integer.decode(nm);
330 if (i < MIN_VALUE || i > MAX_VALUE)
331 throw new NumberFormatException(
332 "Value " + i + " out of range from input " + nm);
333 return valueOf((short)i);
334 }
335
336 /**
337 * The value of the {@code Short}.
338 *
339 * @serial
340 */
341 private final short value;
342
343 /**
344 * Constructs a newly allocated {@code Short} object that
345 * represents the specified {@code short} value.
346 *
347 * @param value the value to be represented by the
348 * {@code Short}.
349 *
350 * @deprecated
351 * It is rarely appropriate to use this constructor. The static factory
352 * {@link #valueOf(short)} is generally a better choice, as it is
353 * likely to yield significantly better space and time performance.
354 */
355 @Deprecated(since="9", forRemoval = true)
356 public Short(short value) {
357 this.value = value;
358 }
359
360 /**
361 * Constructs a newly allocated {@code Short} object that
362 * represents the {@code short} value indicated by the
363 * {@code String} parameter. The string is converted to a
364 * {@code short} value in exactly the manner used by the
365 * {@code parseShort} method for radix 10.
366 *
367 * @param s the {@code String} to be converted to a
368 * {@code Short}
369 * @throws NumberFormatException If the {@code String}
370 * does not contain a parsable {@code short}.
371 *
372 * @deprecated
373 * It is rarely appropriate to use this constructor.
374 * Use {@link #parseShort(String)} to convert a string to a
375 * {@code short} primitive, or use {@link #valueOf(String)}
376 * to convert a string to a {@code Short} object.
377 */
378 @Deprecated(since="9", forRemoval = true)
379 public Short(String s) throws NumberFormatException {
380 this.value = parseShort(s, 10);
381 }
382
383 /**
384 * Returns the value of this {@code Short} as a {@code byte} after
385 * a narrowing primitive conversion.
386 * @jls 5.1.3 Narrowing Primitive Conversion
387 */
388 public byte byteValue() {
389 return (byte)value;
390 }
391
392 /**
393 * Returns the value of this {@code Short} as a
394 * {@code short}.
395 */
396 @IntrinsicCandidate
397 public short shortValue() {
398 return value;
399 }
400
401 /**
402 * Returns the value of this {@code Short} as an {@code int} after
403 * a widening primitive conversion.
404 * @jls 5.1.2 Widening Primitive Conversion
405 */
406 public int intValue() {
407 return (int)value;
408 }
409
410 /**
411 * Returns the value of this {@code Short} as a {@code long} after
412 * a widening primitive conversion.
413 * @jls 5.1.2 Widening Primitive Conversion
414 */
415 public long longValue() {
416 return (long)value;
417 }
418
419 /**
420 * Returns the value of this {@code Short} as a {@code float}
421 * after a widening primitive conversion.
422 * @jls 5.1.2 Widening Primitive Conversion
423 */
424 public float floatValue() {
425 return (float)value;
426 }
427
428 /**
429 * Returns the value of this {@code Short} as a {@code double}
430 * after a widening primitive conversion.
431 * @jls 5.1.2 Widening Primitive Conversion
432 */
433 public double doubleValue() {
434 return (double)value;
435 }
436
437 /**
438 * Returns a {@code String} object representing this
439 * {@code Short}'s value. The value is converted to signed
440 * decimal representation and returned as a string, exactly as if
441 * the {@code short} value were given as an argument to the
442 * {@link java.lang.Short#toString(short)} method.
443 *
444 * @return a string representation of the value of this object in
445 * base 10.
446 */
447 @Override
448 public String toString() {
449 return Integer.toString(value);
450 }
451
452 /**
453 * Returns a hash code for this {@code Short}; equal to the result
454 * of invoking {@code intValue()}.
455 *
456 * @return a hash code value for this {@code Short}
457 */
458 @Override
459 public int hashCode() {
460 return Short.hashCode(value);
461 }
462
463 /**
464 * Returns a hash code for a {@code short} value; compatible with
465 * {@code Short.hashCode()}.
466 *
467 * @param value the value to hash
468 * @return a hash code value for a {@code short} value.
469 * @since 1.8
470 */
471 public static int hashCode(short value) {
472 return (int)value;
473 }
474
475 /**
476 * Compares this object to the specified object. The result is
477 * {@code true} if and only if the argument is not
478 * {@code null} and is a {@code Short} object that
479 * contains the same {@code short} value as this object.
480 *
481 * @param obj the object to compare with
482 * @return {@code true} if the objects are the same;
483 * {@code false} otherwise.
484 */
485 public boolean equals(Object obj) {
486 if (obj instanceof Short) {
487 return value == ((Short)obj).shortValue();
488 }
489 return false;
490 }
491
492 /**
493 * Compares two {@code Short} objects numerically.
494 *
495 * @param anotherShort the {@code Short} to be compared.
496 * @return the value {@code 0} if this {@code Short} is
497 * equal to the argument {@code Short}; a value less than
498 * {@code 0} if this {@code Short} is numerically less
499 * than the argument {@code Short}; and a value greater than
500 * {@code 0} if this {@code Short} is numerically
501 * greater than the argument {@code Short} (signed
502 * comparison).
503 * @since 1.2
504 */
505 public int compareTo(Short anotherShort) {
506 return compare(this.value, anotherShort.value);
507 }
508
509 /**
510 * Compares two {@code short} values numerically.
511 * The value returned is identical to what would be returned by:
512 * <pre>
513 * Short.valueOf(x).compareTo(Short.valueOf(y))
514 * </pre>
515 *
516 * @param x the first {@code short} to compare
517 * @param y the second {@code short} to compare
518 * @return the value {@code 0} if {@code x == y};
519 * a value less than {@code 0} if {@code x < y}; and
520 * a value greater than {@code 0} if {@code x > y}
521 * @since 1.7
522 */
523 public static int compare(short x, short y) {
524 return x - y;
525 }
526
527 /**
528 * Compares two {@code short} values numerically treating the values
529 * as unsigned.
530 *
531 * @param x the first {@code short} to compare
532 * @param y the second {@code short} to compare
533 * @return the value {@code 0} if {@code x == y}; a value less
534 * than {@code 0} if {@code x < y} as unsigned values; and
535 * a value greater than {@code 0} if {@code x > y} as
536 * unsigned values
537 * @since 9
538 */
539 public static int compareUnsigned(short x, short y) {
540 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
541 }
542
543 /**
544 * The number of bits used to represent a {@code short} value in two's
545 * complement binary form.
546 * @since 1.5
547 */
548 public static final int SIZE = 16;
549
550 /**
551 * The number of bytes used to represent a {@code short} value in two's
552 * complement binary form.
553 *
554 * @since 1.8
555 */
556 public static final int BYTES = SIZE / Byte.SIZE;
557
558 /**
559 * Returns the value obtained by reversing the order of the bytes in the
560 * two's complement representation of the specified {@code short} value.
561 *
562 * @param i the value whose bytes are to be reversed
563 * @return the value obtained by reversing (or, equivalently, swapping)
564 * the bytes in the specified {@code short} value.
565 * @since 1.5
566 */
567 @IntrinsicCandidate
568 public static short reverseBytes(short i) {
569 return (short) (((i & 0xFF00) >> 8) | (i << 8));
570 }
571
572
573 /**
574 * Converts the argument to an {@code int} by an unsigned
575 * conversion. In an unsigned conversion to an {@code int}, the
576 * high-order 16 bits of the {@code int} are zero and the
577 * low-order 16 bits are equal to the bits of the {@code short} argument.
578 *
579 * Consequently, zero and positive {@code short} values are mapped
580 * to a numerically equal {@code int} value and negative {@code
581 * short} values are mapped to an {@code int} value equal to the
582 * input plus 2<sup>16</sup>.
583 *
584 * @param x the value to convert to an unsigned {@code int}
585 * @return the argument converted to {@code int} by an unsigned
586 * conversion
587 * @since 1.8
588 */
589 public static int toUnsignedInt(short x) {
590 return ((int) x) & 0xffff;
591 }
592
593 /**
594 * Converts the argument to a {@code long} by an unsigned
595 * conversion. In an unsigned conversion to a {@code long}, the
596 * high-order 48 bits of the {@code long} are zero and the
597 * low-order 16 bits are equal to the bits of the {@code short} argument.
598 *
599 * Consequently, zero and positive {@code short} values are mapped
600 * to a numerically equal {@code long} value and negative {@code
601 * short} values are mapped to a {@code long} value equal to the
602 * input plus 2<sup>16</sup>.
603 *
604 * @param x the value to convert to an unsigned {@code long}
605 * @return the argument converted to {@code long} by an unsigned
606 * conversion
607 * @since 1.8
608 */
609 public static long toUnsignedLong(short x) {
610 return ((long) x) & 0xffffL;
611 }
612
613 /** use serialVersionUID from JDK 1.1. for interoperability */
614 @java.io.Serial
615 private static final long serialVersionUID = 7515723908773894738L;
616 }