1 /*
2 * Copyright 1996-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.lang;
27
28 /**
29 * The {@code Short} class wraps a value of primitive type {@code
30 * short} in an object. An object of type {@code Short} contains a
31 * single field whose type is {@code short}.
32 *
33 * <p>In addition, this class provides several methods for converting
34 * a {@code short} to a {@code String} and a {@code String} to a
35 * {@code short}, as well as other constants and methods useful when
36 * dealing with a {@code short}.
37 *
38 * @author Nakul Saraiya
39 * @author Joseph D. Darcy
40 * @see java.lang.Number
41 * @since JDK1.1
42 */
43 public final class Short extends Number implements Comparable<Short> {
44
45 /**
46 * A constant holding the minimum value a {@code short} can
47 * have, -2<sup>15</sup>.
48 */
49 public static final short MIN_VALUE = -32768;
50
51 /**
52 * A constant holding the maximum value a {@code short} can
53 * have, 2<sup>15</sup>-1.
54 */
55 public static final short MAX_VALUE = 32767;
56
57 /**
58 * The {@code Class} instance representing the primitive type
59 * {@code short}.
60 */
61 public static final Class<Short> TYPE = (Class<Short>) Class.getPrimitiveClass("short");
62
63 /**
64 * Returns a new {@code String} object representing the
65 * specified {@code short}. The radix is assumed to be 10.
66 *
67 * @param s the {@code short} to be converted
68 * @return the string representation of the specified {@code short}
69 * @see java.lang.Integer#toString(int)
70 */
71 public static String toString(short s) {
72 return Integer.toString((int)s, 10);
73 }
74
75 /**
76 * Parses the string argument as a signed {@code short} in the
77 * radix specified by the second argument. The characters in the
78 * string must all be digits, of the specified radix (as
79 * determined by whether {@link java.lang.Character#digit(char,
80 * int)} returns a nonnegative value) except that the first
81 * character may be an ASCII minus sign {@code '-'}
82 * (<code>'\u002D'</code>) to indicate a negative value or an
83 * ASCII plus sign {@code '+'} (<code>'\u002B'</code>) to
84 * indicate a positive value. The resulting {@code short} value
85 * is returned.
86 *
87 * <p>An exception of type {@code NumberFormatException} is
88 * thrown if any of the following situations occurs:
89 * <ul>
90 * <li> The first argument is {@code null} or is a string of
91 * length zero.
92 *
93 * <li> The radix is either smaller than {@link
94 * java.lang.Character#MIN_RADIX} or larger than {@link
95 * java.lang.Character#MAX_RADIX}.
96 *
97 * <li> Any character of the string is not a digit of the
98 * specified radix, except that the first character may be a minus
99 * sign {@code '-'} (<code>'\u002D'</code>) or plus sign
100 * {@code '+'} (<code>'\u002B'</code>) provided that the
101 * string is longer than length 1.
102 *
103 * <li> The value represented by the string is not a value of type
104 * {@code short}.
105 * </ul>
106 *
107 * @param s the {@code String} containing the
108 * {@code short} representation to be parsed
109 * @param radix the radix to be used while parsing {@code s}
110 * @return the {@code short} represented by the string
111 * argument in the specified radix.
112 * @throws NumberFormatException If the {@code String}
113 * does not contain a parsable {@code short}.
114 */
115 public static short parseShort(String s, int radix)
116 throws NumberFormatException {
117 int i = Integer.parseInt(s, radix);
118 if (i < MIN_VALUE || i > MAX_VALUE)
119 throw new NumberFormatException(
120 "Value out of range. Value:\"" + s + "\" Radix:" + radix);
121 return (short)i;
122 }
123
124 /**
125 * Parses the string argument as a signed decimal {@code
126 * short}. The characters in the string must all be decimal
127 * digits, except that the first character may be an ASCII minus
128 * sign {@code '-'} (<code>'\u002D'</code>) to indicate a
129 * negative value or an ASCII plus sign {@code '+'}
130 * (<code>'\u002B'</code>) to indicate a positive value. The
131 * resulting {@code short} value is returned, exactly as if the
132 * argument and the radix 10 were given as arguments to the {@link
133 * #parseShort(java.lang.String, int)} method.
134 *
135 * @param s a {@code String} containing the {@code short}
136 * representation to be parsed
137 * @return the {@code short} value represented by the
138 * argument in decimal.
139 * @throws NumberFormatException If the string does not
140 * contain a parsable {@code short}.
141 */
142 public static short parseShort(String s) throws NumberFormatException {
143 return parseShort(s, 10);
144 }
145
146 /**
147 * Returns a {@code Short} object holding the value
148 * extracted from the specified {@code String} when parsed
149 * with the radix given by the second argument. The first argument
150 * is interpreted as representing a signed {@code short} in
151 * the radix specified by the second argument, exactly as if the
152 * argument were given to the {@link #parseShort(java.lang.String,
153 * int)} method. The result is a {@code Short} object that
154 * represents the {@code short} value specified by the string.
155 *
156 * <p>In other words, this method returns a {@code Short} object
157 * equal to the value of:
158 *
159 * <blockquote>
160 * {@code new Short(Short.parseShort(s, radix))}
161 * </blockquote>
162 *
163 * @param s the string to be parsed
164 * @param radix the radix to be used in interpreting {@code s}
165 * @return a {@code Short} object holding the value
166 * represented by the string argument in the
167 * specified radix.
168 * @throws NumberFormatException If the {@code String} does
169 * not contain a parsable {@code short}.
170 */
171 public static Short valueOf(String s, int radix)
172 throws NumberFormatException {
173 return new Short(parseShort(s, radix));
174 }
175
176 /**
177 * Returns a {@code Short} object holding the
178 * value given by the specified {@code String}. The argument
179 * is interpreted as representing a signed decimal
180 * {@code short}, exactly as if the argument were given to
181 * the {@link #parseShort(java.lang.String)} method. The result is
182 * a {@code Short} object that represents the
183 * {@code short} value specified by the string.
184 *
185 * <p>In other words, this method returns a {@code Short} object
186 * equal to the value of:
187 *
188 * <blockquote>
189 * {@code new Short(Short.parseShort(s))}
190 * </blockquote>
191 *
192 * @param s the string to be parsed
193 * @return a {@code Short} object holding the value
194 * represented by the string argument
195 * @throws NumberFormatException If the {@code String} does
196 * not contain a parsable {@code short}.
197 */
198 public static Short valueOf(String s) throws NumberFormatException {
199 return valueOf(s, 10);
200 }
201
202 private static class ShortCache {
203 private ShortCache(){}
204
205 static final Short cache[] = new Short[-(-128) + 127 + 1];
206
207 static {
208 for(int i = 0; i < cache.length; i++)
209 cache[i] = new Short((short)(i - 128));
210 }
211 }
212
213 /**
214 * Returns a {@code Short} instance representing the specified
215 * {@code short} value.
216 * If a new {@code Short} instance is not required, this method
217 * should generally be used in preference to the constructor
218 * {@link #Short(short)}, as this method is likely to yield
219 * significantly better space and time performance by caching
220 * frequently requested values.
221 *
222 * @param s a short value.
223 * @return a {@code Short} instance representing {@code s}.
224 * @since 1.5
225 */
226 public static Short valueOf(short s) {
227 final int offset = 128;
228 int sAsInt = s;
229 if (sAsInt >= -128 && sAsInt <= 127) { // must cache
230 return ShortCache.cache[sAsInt + offset];
231 }
232 return new Short(s);
233 }
234
235 /**
236 * Decodes a {@code String} into a {@code Short}.
237 * Accepts decimal, hexadecimal, and octal numbers given by
238 * the following grammar:
239 *
240 * <blockquote>
241 * <dl>
242 * <dt><i>DecodableString:</i>
243 * <dd><i>Sign<sub>opt</sub> DecimalNumeral</i>
244 * <dd><i>Sign<sub>opt</sub></i> {@code 0x} <i>HexDigits</i>
245 * <dd><i>Sign<sub>opt</sub></i> {@code 0X} <i>HexDigits</i>
246 * <dd><i>Sign<sub>opt</sub></i> {@code #} <i>HexDigits</i>
247 * <dd><i>Sign<sub>opt</sub></i> {@code 0} <i>OctalDigits</i>
248 * <p>
249 * <dt><i>Sign:</i>
250 * <dd>{@code -}
251 * <dd>{@code +}
252 * </dl>
253 * </blockquote>
254 *
255 * <i>DecimalNumeral</i>, <i>HexDigits</i>, and <i>OctalDigits</i>
256 * are defined in <a href="http://java.sun.com/docs/books/jls/second_edition/html/lexical.doc.html#48282">§3.10.1</a>
257 * of the <a href="http://java.sun.com/docs/books/jls/html/">Java
258 * Language Specification</a>.
259 *
260 * <p>The sequence of characters following an optional
261 * sign and/or radix specifier ("{@code 0x}", "{@code 0X}",
262 * "{@code #}", or leading zero) is parsed as by the {@code
263 * Short.parseShort} method with the indicated radix (10, 16, or
264 * 8). This sequence of characters must represent a positive
265 * value or a {@link NumberFormatException} will be thrown. The
266 * result is negated if first character of the specified {@code
267 * String} is the minus sign. No whitespace characters are
268 * permitted in the {@code String}.
269 *
270 * @param nm the {@code String} to decode.
271 * @return a {@code Short} object holding the {@code short}
272 * value represented by {@code nm}
273 * @throws NumberFormatException if the {@code String} does not
274 * contain a parsable {@code short}.
275 * @see java.lang.Short#parseShort(java.lang.String, int)
276 */
277 public static Short decode(String nm) throws NumberFormatException {
278 int i = Integer.decode(nm);
279 if (i < MIN_VALUE || i > MAX_VALUE)
280 throw new NumberFormatException(
281 "Value " + i + " out of range from input " + nm);
282 return (short)i;
283 }
284
285 /**
286 * The value of the {@code Short}.
287 *
288 * @serial
289 */
290 private final short value;
291
292 /**
293 * Constructs a newly allocated {@code Short} object that
294 * represents the specified {@code short} value.
295 *
296 * @param value the value to be represented by the
297 * {@code Short}.
298 */
299 public Short(short value) {
300 this.value = value;
301 }
302
303 /**
304 * Constructs a newly allocated {@code Short} object that
305 * represents the {@code short} value indicated by the
306 * {@code String} parameter. The string is converted to a
307 * {@code short} value in exactly the manner used by the
308 * {@code parseShort} method for radix 10.
309 *
310 * @param s the {@code String} to be converted to a
311 * {@code Short}
312 * @throws NumberFormatException If the {@code String}
313 * does not contain a parsable {@code short}.
314 * @see java.lang.Short#parseShort(java.lang.String, int)
315 */
316 public Short(String s) throws NumberFormatException {
317 this.value = parseShort(s, 10);
318 }
319
320 /**
321 * Returns the value of this {@code Short} as a
322 * {@code byte}.
323 */
324 public byte byteValue() {
325 return (byte)value;
326 }
327
328 /**
329 * Returns the value of this {@code Short} as a
330 * {@code short}.
331 */
332 public short shortValue() {
333 return value;
334 }
335
336 /**
337 * Returns the value of this {@code Short} as an
338 * {@code int}.
339 */
340 public int intValue() {
341 return (int)value;
342 }
343
344 /**
345 * Returns the value of this {@code Short} as a
346 * {@code long}.
347 */
348 public long longValue() {
349 return (long)value;
350 }
351
352 /**
353 * Returns the value of this {@code Short} as a
354 * {@code float}.
355 */
356 public float floatValue() {
357 return (float)value;
358 }
359
360 /**
361 * Returns the value of this {@code Short} as a
362 * {@code double}.
363 */
364 public double doubleValue() {
365 return (double)value;
366 }
367
368 /**
369 * Returns a {@code String} object representing this
370 * {@code Short}'s value. The value is converted to signed
371 * decimal representation and returned as a string, exactly as if
372 * the {@code short} value were given as an argument to the
373 * {@link java.lang.Short#toString(short)} method.
374 *
375 * @return a string representation of the value of this object in
376 * base 10.
377 */
378 public String toString() {
379 return String.valueOf((int)value);
380 }
381
382 /**
383 * Returns a hash code for this {@code Short}.
384 */
385 public int hashCode() {
386 return (int)value;
387 }
388
389 /**
390 * Compares this object to the specified object. The result is
391 * {@code true} if and only if the argument is not
392 * {@code null} and is a {@code Short} object that
393 * contains the same {@code short} value as this object.
394 *
395 * @param obj the object to compare with
396 * @return {@code true} if the objects are the same;
397 * {@code false} otherwise.
398 */
399 public boolean equals(Object obj) {
400 if (obj instanceof Short) {
401 return value == ((Short)obj).shortValue();
402 }
403 return false;
404 }
405
406 /**
407 * Compares two {@code Short} objects numerically.
408 *
409 * @param anotherShort the {@code Short} to be compared.
410 * @return the value {@code 0} if this {@code Short} is
411 * equal to the argument {@code Short}; a value less than
412 * {@code 0} if this {@code Short} is numerically less
413 * than the argument {@code Short}; and a value greater than
414 * {@code 0} if this {@code Short} is numerically
415 * greater than the argument {@code Short} (signed
416 * comparison).
417 * @since 1.2
418 */
419 public int compareTo(Short anotherShort) {
420 return this.value - anotherShort.value;
421 }
422
423 /**
424 * The number of bits used to represent a {@code short} value in two's
425 * complement binary form.
426 * @since 1.5
427 */
428 public static final int SIZE = 16;
429
430 /**
431 * Returns the value obtained by reversing the order of the bytes in the
432 * two's complement representation of the specified {@code short} value.
433 *
434 * @return the value obtained by reversing (or, equivalently, swapping)
435 * the bytes in the specified {@code short} value.
436 * @since 1.5
437 */
438 public static short reverseBytes(short i) {
439 return (short) (((i & 0xFF00) >> 8) | (i << 8));
440 }
441
442 /** use serialVersionUID from JDK 1.1. for interoperability */
443 private static final long serialVersionUID = 7515723908773894738L;
444 }
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