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
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.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 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 @DeserializeConstructor
278 public static Short valueOf(short s) {
279 final int offset = 128;
280 int sAsInt = s;
281 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
282 return ShortCache.cache[sAsInt + offset];
283 }
284 return new Short(s);
285 }
286
287 /**
288 * Decodes a {@code String} into a {@code Short}.
289 * Accepts decimal, hexadecimal, and octal numbers given by
290 * the following grammar:
291 *
292 * <blockquote>
293 * <dl>
294 * <dt><i>DecodableString:</i>
295 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
296 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
297 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
298 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
299 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
300 *
301 * <dt><i>Sign:</i>
302 * <dd>{@code -}
303 * <dd>{@code +}
304 * </dl>
305 * </blockquote>
306 *
307 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
308 * are as defined in section {@jls 3.10.1} of
309 * <cite>The Java Language Specification</cite>,
310 * except that underscores are not accepted between digits.
311 *
312 * <p>The sequence of characters following an optional
313 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
314 * "{@code #}", or leading zero) is parsed as by the {@code
315 * Short.parseShort} method with the indicated radix (10, 16, or
316 * 8). This sequence of characters must represent a positive
317 * value or a {@link NumberFormatException} will be thrown. The
318 * result is negated if first character of the specified {@code
319 * String} is the minus sign. No whitespace characters are
320 * permitted in the {@code String}.
321 *
322 * @param nm the {@code String} to decode.
323 * @return a {@code Short} object holding the {@code short}
324 * value represented by {@code nm}
325 * @throws NumberFormatException if the {@code String} does not
326 * contain a parsable {@code short}.
327 * @see java.lang.Short#parseShort(java.lang.String, int)
328 */
329 public static Short decode(String nm) throws NumberFormatException {
330 int i = Integer.decode(nm);
331 if (i < MIN_VALUE || i > MAX_VALUE)
332 throw new NumberFormatException(
333 "Value " + i + " out of range from input " + nm);
334 return valueOf((short)i);
335 }
336
337 /**
338 * The value of the {@code Short}.
339 *
340 * @serial
341 */
342 private final short value;
343
344 /**
345 * Constructs a newly allocated {@code Short} object that
346 * represents the specified {@code short} value.
347 *
348 * @param value the value to be represented by the
349 * {@code Short}.
350 *
351 * @deprecated
352 * It is rarely appropriate to use this constructor. The static factory
353 * {@link #valueOf(short)} is generally a better choice, as it is
354 * likely to yield significantly better space and time performance.
355 */
356 @Deprecated(since="9", forRemoval = true)
357 public Short(short value) {
358 this.value = value;
359 }
360
361 /**
362 * Constructs a newly allocated {@code Short} object that
363 * represents the {@code short} value indicated by the
364 * {@code String} parameter. The string is converted to a
365 * {@code short} value in exactly the manner used by the
366 * {@code parseShort} method for radix 10.
367 *
368 * @param s the {@code String} to be converted to a
369 * {@code Short}
370 * @throws NumberFormatException If the {@code String}
371 * does not contain a parsable {@code short}.
372 *
373 * @deprecated
374 * It is rarely appropriate to use this constructor.
375 * Use {@link #parseShort(String)} to convert a string to a
376 * {@code short} primitive, or use {@link #valueOf(String)}
377 * to convert a string to a {@code Short} object.
378 */
379 @Deprecated(since="9", forRemoval = true)
380 public Short(String s) throws NumberFormatException {
381 this.value = parseShort(s, 10);
382 }
383
384 /**
385 * Returns the value of this {@code Short} as a {@code byte} after
386 * a narrowing primitive conversion.
387 * @jls 5.1.3 Narrowing Primitive Conversion
388 */
389 public byte byteValue() {
390 return (byte)value;
391 }
392
393 /**
394 * Returns the value of this {@code Short} as a
395 * {@code short}.
396 */
397 @IntrinsicCandidate
398 public short shortValue() {
399 return value;
400 }
401
402 /**
403 * Returns the value of this {@code Short} as an {@code int} after
404 * a widening primitive conversion.
405 * @jls 5.1.2 Widening Primitive Conversion
406 */
407 public int intValue() {
408 return (int)value;
409 }
410
411 /**
412 * Returns the value of this {@code Short} as a {@code long} after
413 * a widening primitive conversion.
414 * @jls 5.1.2 Widening Primitive Conversion
415 */
416 public long longValue() {
417 return (long)value;
418 }
419
420 /**
421 * Returns the value of this {@code Short} as a {@code float}
422 * after a widening primitive conversion.
423 * @jls 5.1.2 Widening Primitive Conversion
424 */
425 public float floatValue() {
426 return (float)value;
427 }
428
429 /**
430 * Returns the value of this {@code Short} as a {@code double}
431 * after a widening primitive conversion.
432 * @jls 5.1.2 Widening Primitive Conversion
433 */
434 public double doubleValue() {
435 return (double)value;
436 }
437
438 /**
439 * Returns a {@code String} object representing this
440 * {@code Short}'s value. The value is converted to signed
441 * decimal representation and returned as a string, exactly as if
442 * the {@code short} value were given as an argument to the
443 * {@link java.lang.Short#toString(short)} method.
444 *
445 * @return a string representation of the value of this object in
446 * base 10.
447 */
448 @Override
449 public String toString() {
450 return Integer.toString(value);
451 }
452
453 /**
454 * Returns a hash code for this {@code Short}; equal to the result
455 * of invoking {@code intValue()}.
456 *
457 * @return a hash code value for this {@code Short}
458 */
459 @Override
460 public int hashCode() {
461 return Short.hashCode(value);
462 }
463
464 /**
465 * Returns a hash code for a {@code short} value; compatible with
466 * {@code Short.hashCode()}.
467 *
468 * @param value the value to hash
469 * @return a hash code value for a {@code short} value.
470 * @since 1.8
471 */
472 public static int hashCode(short value) {
473 return (int)value;
474 }
475
476 /**
477 * Compares this object to the specified object. The result is
478 * {@code true} if and only if the argument is not
479 * {@code null} and is a {@code Short} object that
480 * contains the same {@code short} value as this object.
481 *
482 * @param obj the object to compare with
483 * @return {@code true} if the objects are the same;
484 * {@code false} otherwise.
485 */
486 public boolean equals(Object obj) {
487 if (obj instanceof Short) {
488 return value == ((Short)obj).shortValue();
489 }
490 return false;
491 }
492
493 /**
494 * Compares two {@code Short} objects numerically.
495 *
496 * @param anotherShort the {@code Short} to be compared.
497 * @return the value {@code 0} if this {@code Short} is
498 * equal to the argument {@code Short}; a value less than
499 * {@code 0} if this {@code Short} is numerically less
500 * than the argument {@code Short}; and a value greater than
501 * {@code 0} if this {@code Short} is numerically
502 * greater than the argument {@code Short} (signed
503 * comparison).
504 * @since 1.2
505 */
506 public int compareTo(Short anotherShort) {
507 return compare(this.value, anotherShort.value);
508 }
509
510 /**
511 * Compares two {@code short} values numerically.
512 * The value returned is identical to what would be returned by:
513 * <pre>
514 * Short.valueOf(x).compareTo(Short.valueOf(y))
515 * </pre>
516 *
517 * @param x the first {@code short} to compare
518 * @param y the second {@code short} to compare
519 * @return the value {@code 0} if {@code x == y};
520 * a value less than {@code 0} if {@code x < y}; and
521 * a value greater than {@code 0} if {@code x > y}
522 * @since 1.7
523 */
524 public static int compare(short x, short y) {
525 return x - y;
526 }
527
528 /**
529 * Compares two {@code short} values numerically treating the values
530 * as unsigned.
531 *
532 * @param x the first {@code short} to compare
533 * @param y the second {@code short} to compare
534 * @return the value {@code 0} if {@code x == y}; a value less
535 * than {@code 0} if {@code x < y} as unsigned values; and
536 * a value greater than {@code 0} if {@code x > y} as
537 * unsigned values
538 * @since 9
539 */
540 public static int compareUnsigned(short x, short y) {
541 return Short.toUnsignedInt(x) - Short.toUnsignedInt(y);
542 }
543
544 /**
545 * The number of bits used to represent a {@code short} value in two's
546 * complement binary form.
547 * @since 1.5
548 */
549 public static final int SIZE = 16;
550
551 /**
552 * The number of bytes used to represent a {@code short} value in two's
553 * complement binary form.
554 *
555 * @since 1.8
556 */
557 public static final int BYTES = SIZE / Byte.SIZE;
558
559 /**
560 * Returns the value obtained by reversing the order of the bytes in the
561 * two's complement representation of the specified {@code short} value.
562 *
563 * @param i the value whose bytes are to be reversed
564 * @return the value obtained by reversing (or, equivalently, swapping)
565 * the bytes in the specified {@code short} value.
566 * @since 1.5
567 */
568 @IntrinsicCandidate
569 public static short reverseBytes(short i) {
570 return (short) (((i & 0xFF00) >> 8) | (i << 8));
571 }
572
573
574 /**
575 * Converts the argument to an {@code int} by an unsigned
576 * conversion. In an unsigned conversion to an {@code int}, the
577 * high-order 16 bits of the {@code int} are zero and the
578 * low-order 16 bits are equal to the bits of the {@code short} argument.
579 *
580 * Consequently, zero and positive {@code short} values are mapped
581 * to a numerically equal {@code int} value and negative {@code
582 * short} values are mapped to an {@code int} value equal to the
583 * input plus 2<sup>16</sup>.
584 *
585 * @param x the value to convert to an unsigned {@code int}
586 * @return the argument converted to {@code int} by an unsigned
587 * conversion
588 * @since 1.8
589 */
590 public static int toUnsignedInt(short x) {
591 return ((int) x) & 0xffff;
592 }
593
594 /**
595 * Converts the argument to a {@code long} by an unsigned
596 * conversion. In an unsigned conversion to a {@code long}, the
597 * high-order 48 bits of the {@code long} are zero and the
598 * low-order 16 bits are equal to the bits of the {@code short} argument.
599 *
600 * Consequently, zero and positive {@code short} values are mapped
601 * to a numerically equal {@code long} value and negative {@code
602 * short} values are mapped to a {@code long} value equal to the
603 * input plus 2<sup>16</sup>.
604 *
605 * @param x the value to convert to an unsigned {@code long}
606 * @return the argument converted to {@code long} by an unsigned
607 * conversion
608 * @since 1.8
609 */
610 public static long toUnsignedLong(short x) {
611 return ((long) x) & 0xffffL;
612 }
613
614 /** use serialVersionUID from JDK 1.1. for interoperability */
615 @java.io.Serial
616 private static final long serialVersionUID = 7515723908773894738L;
617 }