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