1 /*
2 * Copyright (c) 1994, 2019, 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 java.lang.invoke.MethodHandles;
29 import java.lang.constant.Constable;
30 import java.lang.constant.ConstantDesc;
31 import java.util.Optional;
32
33 import jdk.internal.math.FloatingDecimal;
34 import jdk.internal.math.DoubleConsts;
35 import jdk.internal.HotSpotIntrinsicCandidate;
36
37 /**
38 * The {@code Double} class wraps a value of the primitive type
39 * {@code double} in an object. An object of type
40 * {@code Double} contains a single field whose type is
41 * {@code double}.
42 *
43 * <p>In addition, this class provides several methods for converting a
44 * {@code double} to a {@code String} and a
45 * {@code String} to a {@code double}, as well as other
46 * constants and methods useful when dealing with a
47 * {@code double}.
48 *
49 * @author Lee Boynton
50 * @author Arthur van Hoff
51 * @author Joseph D. Darcy
52 * @since 1.0
53 */
54 public final class Double extends Number
55 implements Comparable<Double>, Constable, ConstantDesc {
56 /**
57 * A constant holding the positive infinity of type
58 * {@code double}. It is equal to the value returned by
59 * {@code Double.longBitsToDouble(0x7ff0000000000000L)}.
60 */
61 public static final double POSITIVE_INFINITY = 1.0 / 0.0;
62
63 /**
64 * A constant holding the negative infinity of type
65 * {@code double}. It is equal to the value returned by
66 * {@code Double.longBitsToDouble(0xfff0000000000000L)}.
67 */
68 public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
69
70 /**
71 * A constant holding a Not-a-Number (NaN) value of type
72 * {@code double}. It is equivalent to the value returned by
73 * {@code Double.longBitsToDouble(0x7ff8000000000000L)}.
74 */
75 public static final double NaN = 0.0d / 0.0;
76
77 /**
78 * A constant holding the largest positive finite value of type
79 * {@code double},
80 * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to
81 * the hexadecimal floating-point literal
82 * {@code 0x1.fffffffffffffP+1023} and also equal to
83 * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}.
84 */
85 public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308
86
87 /**
88 * A constant holding the smallest positive normal value of type
89 * {@code double}, 2<sup>-1022</sup>. It is equal to the
90 * hexadecimal floating-point literal {@code 0x1.0p-1022} and also
91 * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}.
92 *
93 * @since 1.6
94 */
95 public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308
96
97 /**
98 * A constant holding the smallest positive nonzero value of type
99 * {@code double}, 2<sup>-1074</sup>. It is equal to the
100 * hexadecimal floating-point literal
101 * {@code 0x0.0000000000001P-1022} and also equal to
102 * {@code Double.longBitsToDouble(0x1L)}.
103 */
104 public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324
105
106 /**
107 * Maximum exponent a finite {@code double} variable may have.
108 * It is equal to the value returned by
109 * {@code Math.getExponent(Double.MAX_VALUE)}.
110 *
111 * @since 1.6
112 */
113 public static final int MAX_EXPONENT = 1023;
114
115 /**
116 * Minimum exponent a normalized {@code double} variable may
117 * have. It is equal to the value returned by
118 * {@code Math.getExponent(Double.MIN_NORMAL)}.
119 *
120 * @since 1.6
121 */
122 public static final int MIN_EXPONENT = -1022;
123
124 /**
125 * The number of bits used to represent a {@code double} value.
126 *
127 * @since 1.5
128 */
129 public static final int SIZE = 64;
130
131 /**
132 * The number of bytes used to represent a {@code double} value.
133 *
134 * @since 1.8
135 */
136 public static final int BYTES = SIZE / Byte.SIZE;
137
138 /**
139 * The {@code Class} instance representing the primitive type
140 * {@code double}.
141 *
142 * @since 1.1
143 */
144 @SuppressWarnings("unchecked")
145 public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double");
146
147 /**
148 * Returns a string representation of the {@code double}
149 * argument. All characters mentioned below are ASCII characters.
150 * <ul>
151 * <li>If the argument is NaN, the result is the string
152 * "{@code NaN}".
153 * <li>Otherwise, the result is a string that represents the sign and
154 * magnitude (absolute value) of the argument. If the sign is negative,
155 * the first character of the result is '{@code -}'
156 * ({@code '\u005Cu002D'}); if the sign is positive, no sign character
157 * appears in the result. As for the magnitude <i>m</i>:
158 * <ul>
159 * <li>If <i>m</i> is infinity, it is represented by the characters
160 * {@code "Infinity"}; thus, positive infinity produces the result
161 * {@code "Infinity"} and negative infinity produces the result
162 * {@code "-Infinity"}.
163 *
164 * <li>If <i>m</i> is zero, it is represented by the characters
165 * {@code "0.0"}; thus, negative zero produces the result
166 * {@code "-0.0"} and positive zero produces the result
167 * {@code "0.0"}.
168 *
169 * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less
170 * than 10<sup>7</sup>, then it is represented as the integer part of
171 * <i>m</i>, in decimal form with no leading zeroes, followed by
172 * '{@code .}' ({@code '\u005Cu002E'}), followed by one or
173 * more decimal digits representing the fractional part of <i>m</i>.
174 *
175 * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or
176 * equal to 10<sup>7</sup>, then it is represented in so-called
177 * "computerized scientific notation." Let <i>n</i> be the unique
178 * integer such that 10<sup><i>n</i></sup> ≤ <i>m</i> {@literal <}
179 * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the
180 * mathematically exact quotient of <i>m</i> and
181 * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10. The
182 * magnitude is then represented as the integer part of <i>a</i>,
183 * as a single decimal digit, followed by '{@code .}'
184 * ({@code '\u005Cu002E'}), followed by decimal digits
185 * representing the fractional part of <i>a</i>, followed by the
186 * letter '{@code E}' ({@code '\u005Cu0045'}), followed
187 * by a representation of <i>n</i> as a decimal integer, as
188 * produced by the method {@link Integer#toString(int)}.
189 * </ul>
190 * </ul>
191 * How many digits must be printed for the fractional part of
192 * <i>m</i> or <i>a</i>? There must be at least one digit to represent
193 * the fractional part, and beyond that as many, but only as many, more
194 * digits as are needed to uniquely distinguish the argument value from
195 * adjacent values of type {@code double}. That is, suppose that
196 * <i>x</i> is the exact mathematical value represented by the decimal
197 * representation produced by this method for a finite nonzero argument
198 * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest
199 * to <i>x</i>; or if two {@code double} values are equally close
200 * to <i>x</i>, then <i>d</i> must be one of them and the least
201 * significant bit of the significand of <i>d</i> must be {@code 0}.
202 *
203 * <p>To create localized string representations of a floating-point
204 * value, use subclasses of {@link java.text.NumberFormat}.
205 *
206 * @param d the {@code double} to be converted.
207 * @return a string representation of the argument.
208 */
209 public static String toString(double d) {
210 return FloatingDecimal.toJavaFormatString(d);
211 }
212
213 /**
214 * Returns a hexadecimal string representation of the
215 * {@code double} argument. All characters mentioned below
216 * are ASCII characters.
217 *
218 * <ul>
219 * <li>If the argument is NaN, the result is the string
220 * "{@code NaN}".
221 * <li>Otherwise, the result is a string that represents the sign
222 * and magnitude of the argument. If the sign is negative, the
223 * first character of the result is '{@code -}'
224 * ({@code '\u005Cu002D'}); if the sign is positive, no sign
225 * character appears in the result. As for the magnitude <i>m</i>:
226 *
227 * <ul>
228 * <li>If <i>m</i> is infinity, it is represented by the string
229 * {@code "Infinity"}; thus, positive infinity produces the
230 * result {@code "Infinity"} and negative infinity produces
231 * the result {@code "-Infinity"}.
232 *
233 * <li>If <i>m</i> is zero, it is represented by the string
234 * {@code "0x0.0p0"}; thus, negative zero produces the result
235 * {@code "-0x0.0p0"} and positive zero produces the result
236 * {@code "0x0.0p0"}.
237 *
238 * <li>If <i>m</i> is a {@code double} value with a
239 * normalized representation, substrings are used to represent the
240 * significand and exponent fields. The significand is
241 * represented by the characters {@code "0x1."}
242 * followed by a lowercase hexadecimal representation of the rest
243 * of the significand as a fraction. Trailing zeros in the
244 * hexadecimal representation are removed unless all the digits
245 * are zero, in which case a single zero is used. Next, the
246 * exponent is represented by {@code "p"} followed
247 * by a decimal string of the unbiased exponent as if produced by
248 * a call to {@link Integer#toString(int) Integer.toString} on the
249 * exponent value.
250 *
251 * <li>If <i>m</i> is a {@code double} value with a subnormal
252 * representation, the significand is represented by the
253 * characters {@code "0x0."} followed by a
254 * hexadecimal representation of the rest of the significand as a
255 * fraction. Trailing zeros in the hexadecimal representation are
256 * removed. Next, the exponent is represented by
257 * {@code "p-1022"}. Note that there must be at
258 * least one nonzero digit in a subnormal significand.
259 *
260 * </ul>
261 *
262 * </ul>
263 *
264 * <table class="striped">
265 * <caption>Examples</caption>
266 * <thead>
267 * <tr><th scope="col">Floating-point Value</th><th scope="col">Hexadecimal String</th>
268 * </thead>
269 * <tbody style="text-align:right">
270 * <tr><th scope="row">{@code 1.0}</th> <td>{@code 0x1.0p0}</td>
271 * <tr><th scope="row">{@code -1.0}</th> <td>{@code -0x1.0p0}</td>
272 * <tr><th scope="row">{@code 2.0}</th> <td>{@code 0x1.0p1}</td>
273 * <tr><th scope="row">{@code 3.0}</th> <td>{@code 0x1.8p1}</td>
274 * <tr><th scope="row">{@code 0.5}</th> <td>{@code 0x1.0p-1}</td>
275 * <tr><th scope="row">{@code 0.25}</th> <td>{@code 0x1.0p-2}</td>
276 * <tr><th scope="row">{@code Double.MAX_VALUE}</th>
277 * <td>{@code 0x1.fffffffffffffp1023}</td>
278 * <tr><th scope="row">{@code Minimum Normal Value}</th>
279 * <td>{@code 0x1.0p-1022}</td>
280 * <tr><th scope="row">{@code Maximum Subnormal Value}</th>
281 * <td>{@code 0x0.fffffffffffffp-1022}</td>
282 * <tr><th scope="row">{@code Double.MIN_VALUE}</th>
283 * <td>{@code 0x0.0000000000001p-1022}</td>
284 * </tbody>
285 * </table>
286 * @param d the {@code double} to be converted.
287 * @return a hex string representation of the argument.
288 * @since 1.5
289 * @author Joseph D. Darcy
290 */
291 public static String toHexString(double d) {
292 /*
293 * Modeled after the "a" conversion specifier in C99, section
294 * 7.19.6.1; however, the output of this method is more
295 * tightly specified.
296 */
297 if (!isFinite(d) )
298 // For infinity and NaN, use the decimal output.
299 return Double.toString(d);
300 else {
301 // Initialized to maximum size of output.
302 StringBuilder answer = new StringBuilder(24);
303
304 if (Math.copySign(1.0, d) == -1.0) // value is negative,
305 answer.append("-"); // so append sign info
306
307 answer.append("0x");
308
309 d = Math.abs(d);
310
311 if(d == 0.0) {
312 answer.append("0.0p0");
313 } else {
314 boolean subnormal = (d < Double.MIN_NORMAL);
315
316 // Isolate significand bits and OR in a high-order bit
317 // so that the string representation has a known
318 // length.
319 long signifBits = (Double.doubleToLongBits(d)
320 & DoubleConsts.SIGNIF_BIT_MASK) |
321 0x1000000000000000L;
322
323 // Subnormal values have a 0 implicit bit; normal
324 // values have a 1 implicit bit.
325 answer.append(subnormal ? "0." : "1.");
326
327 // Isolate the low-order 13 digits of the hex
328 // representation. If all the digits are zero,
329 // replace with a single 0; otherwise, remove all
330 // trailing zeros.
331 String signif = Long.toHexString(signifBits).substring(3,16);
332 answer.append(signif.equals("0000000000000") ? // 13 zeros
333 "0":
334 signif.replaceFirst("0{1,12}$", ""));
335
336 answer.append('p');
337 // If the value is subnormal, use the E_min exponent
338 // value for double; otherwise, extract and report d's
339 // exponent (the representation of a subnormal uses
340 // E_min -1).
341 answer.append(subnormal ?
342 Double.MIN_EXPONENT:
343 Math.getExponent(d));
344 }
345 return answer.toString();
346 }
347 }
348
349 /**
350 * Returns a {@code Double} object holding the
351 * {@code double} value represented by the argument string
352 * {@code s}.
353 *
354 * <p>If {@code s} is {@code null}, then a
355 * {@code NullPointerException} is thrown.
356 *
357 * <p>Leading and trailing whitespace characters in {@code s}
358 * are ignored. Whitespace is removed as if by the {@link
359 * String#trim} method; that is, both ASCII space and control
360 * characters are removed. The rest of {@code s} should
361 * constitute a <i>FloatValue</i> as described by the lexical
362 * syntax rules:
363 *
364 * <blockquote>
365 * <dl>
366 * <dt><i>FloatValue:</i>
367 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
368 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
369 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
370 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
371 * <dd><i>SignedInteger</i>
372 * </dl>
373 *
374 * <dl>
375 * <dt><i>HexFloatingPointLiteral</i>:
376 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
377 * </dl>
378 *
379 * <dl>
380 * <dt><i>HexSignificand:</i>
381 * <dd><i>HexNumeral</i>
382 * <dd><i>HexNumeral</i> {@code .}
383 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
384 * </i>{@code .}<i> HexDigits</i>
385 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
386 * </i>{@code .} <i>HexDigits</i>
387 * </dl>
388 *
389 * <dl>
390 * <dt><i>BinaryExponent:</i>
391 * <dd><i>BinaryExponentIndicator SignedInteger</i>
392 * </dl>
393 *
394 * <dl>
395 * <dt><i>BinaryExponentIndicator:</i>
396 * <dd>{@code p}
397 * <dd>{@code P}
398 * </dl>
399 *
400 * </blockquote>
401 *
402 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
403 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
404 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
405 * sections of
406 * <cite>The Java™ Language Specification</cite>,
407 * except that underscores are not accepted between digits.
408 * If {@code s} does not have the form of
409 * a <i>FloatValue</i>, then a {@code NumberFormatException}
410 * is thrown. Otherwise, {@code s} is regarded as
411 * representing an exact decimal value in the usual
412 * "computerized scientific notation" or as an exact
413 * hexadecimal value; this exact numerical value is then
414 * conceptually converted to an "infinitely precise"
415 * binary value that is then rounded to type {@code double}
416 * by the usual round-to-nearest rule of IEEE 754 floating-point
417 * arithmetic, which includes preserving the sign of a zero
418 * value.
419 *
420 * Note that the round-to-nearest rule also implies overflow and
421 * underflow behaviour; if the exact value of {@code s} is large
422 * enough in magnitude (greater than or equal to ({@link
423 * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2),
424 * rounding to {@code double} will result in an infinity and if the
425 * exact value of {@code s} is small enough in magnitude (less
426 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
427 * result in a zero.
428 *
429 * Finally, after rounding a {@code Double} object representing
430 * this {@code double} value is returned.
431 *
432 * <p> To interpret localized string representations of a
433 * floating-point value, use subclasses of {@link
434 * java.text.NumberFormat}.
435 *
436 * <p>Note that trailing format specifiers, specifiers that
437 * determine the type of a floating-point literal
438 * ({@code 1.0f} is a {@code float} value;
439 * {@code 1.0d} is a {@code double} value), do
440 * <em>not</em> influence the results of this method. In other
441 * words, the numerical value of the input string is converted
442 * directly to the target floating-point type. The two-step
443 * sequence of conversions, string to {@code float} followed
444 * by {@code float} to {@code double}, is <em>not</em>
445 * equivalent to converting a string directly to
446 * {@code double}. For example, the {@code float}
447 * literal {@code 0.1f} is equal to the {@code double}
448 * value {@code 0.10000000149011612}; the {@code float}
449 * literal {@code 0.1f} represents a different numerical
450 * value than the {@code double} literal
451 * {@code 0.1}. (The numerical value 0.1 cannot be exactly
452 * represented in a binary floating-point number.)
453 *
454 * <p>To avoid calling this method on an invalid string and having
455 * a {@code NumberFormatException} be thrown, the regular
456 * expression below can be used to screen the input string:
457 *
458 * <pre>{@code
459 * final String Digits = "(\\p{Digit}+)";
460 * final String HexDigits = "(\\p{XDigit}+)";
461 * // an exponent is 'e' or 'E' followed by an optionally
462 * // signed decimal integer.
463 * final String Exp = "[eE][+-]?"+Digits;
464 * final String fpRegex =
465 * ("[\\x00-\\x20]*"+ // Optional leading "whitespace"
466 * "[+-]?(" + // Optional sign character
467 * "NaN|" + // "NaN" string
468 * "Infinity|" + // "Infinity" string
469 *
470 * // A decimal floating-point string representing a finite positive
471 * // number without a leading sign has at most five basic pieces:
472 * // Digits . Digits ExponentPart FloatTypeSuffix
473 * //
474 * // Since this method allows integer-only strings as input
475 * // in addition to strings of floating-point literals, the
476 * // two sub-patterns below are simplifications of the grammar
477 * // productions from section 3.10.2 of
478 * // The Java Language Specification.
479 *
480 * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt
481 * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+
482 *
483 * // . Digits ExponentPart_opt FloatTypeSuffix_opt
484 * "(\\.("+Digits+")("+Exp+")?)|"+
485 *
486 * // Hexadecimal strings
487 * "((" +
488 * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt
489 * "(0[xX]" + HexDigits + "(\\.)?)|" +
490 *
491 * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt
492 * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +
493 *
494 * ")[pP][+-]?" + Digits + "))" +
495 * "[fFdD]?))" +
496 * "[\\x00-\\x20]*");// Optional trailing "whitespace"
497 *
498 * if (Pattern.matches(fpRegex, myString))
499 * Double.valueOf(myString); // Will not throw NumberFormatException
500 * else {
501 * // Perform suitable alternative action
502 * }
503 * }</pre>
504 *
505 * @param s the string to be parsed.
506 * @return a {@code Double} object holding the value
507 * represented by the {@code String} argument.
508 * @throws NumberFormatException if the string does not contain a
509 * parsable number.
510 */
511 public static Double valueOf(String s) throws NumberFormatException {
512 return new Double(parseDouble(s));
513 }
514
515 /**
516 * Returns a {@code Double} instance representing the specified
517 * {@code double} value.
518 * If a new {@code Double} instance is not required, this method
519 * should generally be used in preference to the constructor
520 * {@link #Double(double)}, as this method is likely to yield
521 * significantly better space and time performance by caching
522 * frequently requested values.
523 *
524 * @param d a double value.
525 * @return a {@code Double} instance representing {@code d}.
526 * @since 1.5
527 */
528 @HotSpotIntrinsicCandidate
529 public static Double valueOf(double d) {
530 return new Double(d);
531 }
532
533 /**
534 * Returns a new {@code double} initialized to the value
535 * represented by the specified {@code String}, as performed
536 * by the {@code valueOf} method of class
537 * {@code Double}.
538 *
539 * @param s the string to be parsed.
540 * @return the {@code double} value represented by the string
541 * argument.
542 * @throws NullPointerException if the string is null
543 * @throws NumberFormatException if the string does not contain
544 * a parsable {@code double}.
545 * @see java.lang.Double#valueOf(String)
546 * @since 1.2
547 */
548 public static double parseDouble(String s) throws NumberFormatException {
549 return FloatingDecimal.parseDouble(s);
550 }
551
552 /**
553 * Returns {@code true} if the specified number is a
554 * Not-a-Number (NaN) value, {@code false} otherwise.
555 *
556 * @param v the value to be tested.
557 * @return {@code true} if the value of the argument is NaN;
558 * {@code false} otherwise.
559 */
560 public static boolean isNaN(double v) {
561 return (v != v);
562 }
563
564 /**
565 * Returns {@code true} if the specified number is infinitely
566 * large in magnitude, {@code false} otherwise.
567 *
568 * @param v the value to be tested.
569 * @return {@code true} if the value of the argument is positive
570 * infinity or negative infinity; {@code false} otherwise.
571 */
572 public static boolean isInfinite(double v) {
573 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
574 }
575
576 /**
577 * Returns {@code true} if the argument is a finite floating-point
578 * value; returns {@code false} otherwise (for NaN and infinity
579 * arguments).
580 *
581 * @param d the {@code double} value to be tested
582 * @return {@code true} if the argument is a finite
583 * floating-point value, {@code false} otherwise.
584 * @since 1.8
585 */
586 public static boolean isFinite(double d) {
587 return Math.abs(d) <= Double.MAX_VALUE;
588 }
589
590 /**
591 * The value of the Double.
592 *
593 * @serial
594 */
595 private final double value;
596
597 /**
598 * Constructs a newly allocated {@code Double} object that
599 * represents the primitive {@code double} argument.
600 *
601 * @param value the value to be represented by the {@code Double}.
602 *
603 * @deprecated
604 * It is rarely appropriate to use this constructor. The static factory
605 * {@link #valueOf(double)} is generally a better choice, as it is
606 * likely to yield significantly better space and time performance.
607 */
608 @Deprecated(since="9")
609 public Double(double value) {
610 this.value = value;
611 }
612
613 /**
614 * Constructs a newly allocated {@code Double} object that
615 * represents the floating-point value of type {@code double}
616 * represented by the string. The string is converted to a
617 * {@code double} value as if by the {@code valueOf} method.
618 *
619 * @param s a string to be converted to a {@code Double}.
620 * @throws NumberFormatException if the string does not contain a
621 * parsable number.
622 *
623 * @deprecated
624 * It is rarely appropriate to use this constructor.
625 * Use {@link #parseDouble(String)} to convert a string to a
626 * {@code double} primitive, or use {@link #valueOf(String)}
627 * to convert a string to a {@code Double} object.
628 */
629 @Deprecated(since="9")
630 public Double(String s) throws NumberFormatException {
631 value = parseDouble(s);
632 }
633
634 /**
635 * Returns {@code true} if this {@code Double} value is
636 * a Not-a-Number (NaN), {@code false} otherwise.
637 *
638 * @return {@code true} if the value represented by this object is
639 * NaN; {@code false} otherwise.
640 */
641 public boolean isNaN() {
642 return isNaN(value);
643 }
644
645 /**
646 * Returns {@code true} if this {@code Double} value is
647 * infinitely large in magnitude, {@code false} otherwise.
648 *
649 * @return {@code true} if the value represented by this object is
650 * positive infinity or negative infinity;
651 * {@code false} otherwise.
652 */
653 public boolean isInfinite() {
654 return isInfinite(value);
655 }
656
657 /**
658 * Returns a string representation of this {@code Double} object.
659 * The primitive {@code double} value represented by this
660 * object is converted to a string exactly as if by the method
661 * {@code toString} of one argument.
662 *
663 * @return a {@code String} representation of this object.
664 * @see java.lang.Double#toString(double)
665 */
666 public String toString() {
667 return toString(value);
668 }
669
670 /**
671 * Returns the value of this {@code Double} as a {@code byte}
672 * after a narrowing primitive conversion.
673 *
674 * @return the {@code double} value represented by this object
675 * converted to type {@code byte}
676 * @jls 5.1.3 Narrowing Primitive Conversion
677 * @since 1.1
678 */
679 public byte byteValue() {
680 return (byte)value;
681 }
682
683 /**
684 * Returns the value of this {@code Double} as a {@code short}
685 * after a narrowing primitive conversion.
686 *
687 * @return the {@code double} value represented by this object
688 * converted to type {@code short}
689 * @jls 5.1.3 Narrowing Primitive Conversion
690 * @since 1.1
691 */
692 public short shortValue() {
693 return (short)value;
694 }
695
696 /**
697 * Returns the value of this {@code Double} as an {@code int}
698 * after a narrowing primitive conversion.
699 * @jls 5.1.3 Narrowing Primitive Conversion
700 *
701 * @return the {@code double} value represented by this object
702 * converted to type {@code int}
703 */
704 public int intValue() {
705 return (int)value;
706 }
707
708 /**
709 * Returns the value of this {@code Double} as a {@code long}
710 * after a narrowing primitive conversion.
711 *
712 * @return the {@code double} value represented by this object
713 * converted to type {@code long}
714 * @jls 5.1.3 Narrowing Primitive Conversion
715 */
716 public long longValue() {
717 return (long)value;
718 }
719
720 /**
721 * Returns the value of this {@code Double} as a {@code float}
722 * after a narrowing primitive conversion.
723 *
724 * @return the {@code double} value represented by this object
725 * converted to type {@code float}
726 * @jls 5.1.3 Narrowing Primitive Conversion
727 * @since 1.0
728 */
729 public float floatValue() {
730 return (float)value;
731 }
732
733 /**
734 * Returns the {@code double} value of this {@code Double} object.
735 *
736 * @return the {@code double} value represented by this object
737 */
738 @HotSpotIntrinsicCandidate
739 public double doubleValue() {
740 return value;
741 }
742
743 /**
744 * Returns a hash code for this {@code Double} object. The
745 * result is the exclusive OR of the two halves of the
746 * {@code long} integer bit representation, exactly as
747 * produced by the method {@link #doubleToLongBits(double)}, of
748 * the primitive {@code double} value represented by this
749 * {@code Double} object. That is, the hash code is the value
750 * of the expression:
751 *
752 * <blockquote>
753 * {@code (int)(v^(v>>>32))}
754 * </blockquote>
755 *
756 * where {@code v} is defined by:
757 *
758 * <blockquote>
759 * {@code long v = Double.doubleToLongBits(this.doubleValue());}
760 * </blockquote>
761 *
762 * @return a {@code hash code} value for this object.
763 */
764 @Override
765 public int hashCode() {
766 return Double.hashCode(value);
767 }
768
769 /**
770 * Returns a hash code for a {@code double} value; compatible with
771 * {@code Double.hashCode()}.
772 *
773 * @param value the value to hash
774 * @return a hash code value for a {@code double} value.
775 * @since 1.8
776 */
777 public static int hashCode(double value) {
778 long bits = doubleToLongBits(value);
779 return (int)(bits ^ (bits >>> 32));
780 }
781
782 /**
783 * Compares this object against the specified object. The result
784 * is {@code true} if and only if the argument is not
785 * {@code null} and is a {@code Double} object that
786 * represents a {@code double} that has the same value as the
787 * {@code double} represented by this object. For this
788 * purpose, two {@code double} values are considered to be
789 * the same if and only if the method {@link
790 * #doubleToLongBits(double)} returns the identical
791 * {@code long} value when applied to each.
792 *
793 * <p>Note that in most cases, for two instances of class
794 * {@code Double}, {@code d1} and {@code d2}, the
795 * value of {@code d1.equals(d2)} is {@code true} if and
796 * only if
797 *
798 * <blockquote>
799 * {@code d1.doubleValue() == d2.doubleValue()}
800 * </blockquote>
801 *
802 * <p>also has the value {@code true}. However, there are two
803 * exceptions:
804 * <ul>
805 * <li>If {@code d1} and {@code d2} both represent
806 * {@code Double.NaN}, then the {@code equals} method
807 * returns {@code true}, even though
808 * {@code Double.NaN==Double.NaN} has the value
809 * {@code false}.
810 * <li>If {@code d1} represents {@code +0.0} while
811 * {@code d2} represents {@code -0.0}, or vice versa,
812 * the {@code equal} test has the value {@code false},
813 * even though {@code +0.0==-0.0} has the value {@code true}.
814 * </ul>
815 * This definition allows hash tables to operate properly.
816 * @param obj the object to compare with.
817 * @return {@code true} if the objects are the same;
818 * {@code false} otherwise.
819 * @see java.lang.Double#doubleToLongBits(double)
820 */
821 public boolean equals(Object obj) {
822 return (obj instanceof Double)
823 && (doubleToLongBits(((Double)obj).value) ==
824 doubleToLongBits(value));
825 }
826
827 /**
828 * Returns a representation of the specified floating-point value
829 * according to the IEEE 754 floating-point "double
830 * format" bit layout.
831 *
832 * <p>Bit 63 (the bit that is selected by the mask
833 * {@code 0x8000000000000000L}) represents the sign of the
834 * floating-point number. Bits
835 * 62-52 (the bits that are selected by the mask
836 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
837 * (the bits that are selected by the mask
838 * {@code 0x000fffffffffffffL}) represent the significand
839 * (sometimes called the mantissa) of the floating-point number.
840 *
841 * <p>If the argument is positive infinity, the result is
842 * {@code 0x7ff0000000000000L}.
843 *
844 * <p>If the argument is negative infinity, the result is
845 * {@code 0xfff0000000000000L}.
846 *
847 * <p>If the argument is NaN, the result is
848 * {@code 0x7ff8000000000000L}.
849 *
850 * <p>In all cases, the result is a {@code long} integer that, when
851 * given to the {@link #longBitsToDouble(long)} method, will produce a
852 * floating-point value the same as the argument to
853 * {@code doubleToLongBits} (except all NaN values are
854 * collapsed to a single "canonical" NaN value).
855 *
856 * @param value a {@code double} precision floating-point number.
857 * @return the bits that represent the floating-point number.
858 */
859 @HotSpotIntrinsicCandidate
860 public static long doubleToLongBits(double value) {
861 if (!isNaN(value)) {
862 return doubleToRawLongBits(value);
863 }
864 return 0x7ff8000000000000L;
865 }
866
867 /**
868 * Returns a representation of the specified floating-point value
869 * according to the IEEE 754 floating-point "double
870 * format" bit layout, preserving Not-a-Number (NaN) values.
871 *
872 * <p>Bit 63 (the bit that is selected by the mask
873 * {@code 0x8000000000000000L}) represents the sign of the
874 * floating-point number. Bits
875 * 62-52 (the bits that are selected by the mask
876 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
877 * (the bits that are selected by the mask
878 * {@code 0x000fffffffffffffL}) represent the significand
879 * (sometimes called the mantissa) of the floating-point number.
880 *
881 * <p>If the argument is positive infinity, the result is
882 * {@code 0x7ff0000000000000L}.
883 *
884 * <p>If the argument is negative infinity, the result is
885 * {@code 0xfff0000000000000L}.
886 *
887 * <p>If the argument is NaN, the result is the {@code long}
888 * integer representing the actual NaN value. Unlike the
889 * {@code doubleToLongBits} method,
890 * {@code doubleToRawLongBits} does not collapse all the bit
891 * patterns encoding a NaN to a single "canonical" NaN
892 * value.
893 *
894 * <p>In all cases, the result is a {@code long} integer that,
895 * when given to the {@link #longBitsToDouble(long)} method, will
896 * produce a floating-point value the same as the argument to
897 * {@code doubleToRawLongBits}.
898 *
899 * @param value a {@code double} precision floating-point number.
900 * @return the bits that represent the floating-point number.
901 * @since 1.3
902 */
903 @HotSpotIntrinsicCandidate
904 public static native long doubleToRawLongBits(double value);
905
906 /**
907 * Returns the {@code double} value corresponding to a given
908 * bit representation.
909 * The argument is considered to be a representation of a
910 * floating-point value according to the IEEE 754 floating-point
911 * "double format" bit layout.
912 *
913 * <p>If the argument is {@code 0x7ff0000000000000L}, the result
914 * is positive infinity.
915 *
916 * <p>If the argument is {@code 0xfff0000000000000L}, the result
917 * is negative infinity.
918 *
919 * <p>If the argument is any value in the range
920 * {@code 0x7ff0000000000001L} through
921 * {@code 0x7fffffffffffffffL} or in the range
922 * {@code 0xfff0000000000001L} through
923 * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE
924 * 754 floating-point operation provided by Java can distinguish
925 * between two NaN values of the same type with different bit
926 * patterns. Distinct values of NaN are only distinguishable by
927 * use of the {@code Double.doubleToRawLongBits} method.
928 *
929 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
930 * values that can be computed from the argument:
931 *
932 * <blockquote><pre>{@code
933 * int s = ((bits >> 63) == 0) ? 1 : -1;
934 * int e = (int)((bits >> 52) & 0x7ffL);
935 * long m = (e == 0) ?
936 * (bits & 0xfffffffffffffL) << 1 :
937 * (bits & 0xfffffffffffffL) | 0x10000000000000L;
938 * }</pre></blockquote>
939 *
940 * Then the floating-point result equals the value of the mathematical
941 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>.
942 *
943 * <p>Note that this method may not be able to return a
944 * {@code double} NaN with exactly same bit pattern as the
945 * {@code long} argument. IEEE 754 distinguishes between two
946 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
947 * differences between the two kinds of NaN are generally not
948 * visible in Java. Arithmetic operations on signaling NaNs turn
949 * them into quiet NaNs with a different, but often similar, bit
950 * pattern. However, on some processors merely copying a
951 * signaling NaN also performs that conversion. In particular,
952 * copying a signaling NaN to return it to the calling method
953 * may perform this conversion. So {@code longBitsToDouble}
954 * may not be able to return a {@code double} with a
955 * signaling NaN bit pattern. Consequently, for some
956 * {@code long} values,
957 * {@code doubleToRawLongBits(longBitsToDouble(start))} may
958 * <i>not</i> equal {@code start}. Moreover, which
959 * particular bit patterns represent signaling NaNs is platform
960 * dependent; although all NaN bit patterns, quiet or signaling,
961 * must be in the NaN range identified above.
962 *
963 * @param bits any {@code long} integer.
964 * @return the {@code double} floating-point value with the same
965 * bit pattern.
966 */
967 @HotSpotIntrinsicCandidate
968 public static native double longBitsToDouble(long bits);
969
970 /**
971 * Compares two {@code Double} objects numerically. There
972 * are two ways in which comparisons performed by this method
973 * differ from those performed by the Java language numerical
974 * comparison operators ({@code <, <=, ==, >=, >})
975 * when applied to primitive {@code double} values:
976 * <ul><li>
977 * {@code Double.NaN} is considered by this method
978 * to be equal to itself and greater than all other
979 * {@code double} values (including
980 * {@code Double.POSITIVE_INFINITY}).
981 * <li>
982 * {@code 0.0d} is considered by this method to be greater
983 * than {@code -0.0d}.
984 * </ul>
985 * This ensures that the <i>natural ordering</i> of
986 * {@code Double} objects imposed by this method is <i>consistent
987 * with equals</i>.
988 *
989 * @param anotherDouble the {@code Double} to be compared.
990 * @return the value {@code 0} if {@code anotherDouble} is
991 * numerically equal to this {@code Double}; a value
992 * less than {@code 0} if this {@code Double}
993 * is numerically less than {@code anotherDouble};
994 * and a value greater than {@code 0} if this
995 * {@code Double} is numerically greater than
996 * {@code anotherDouble}.
997 *
998 * @since 1.2
999 */
1000 public int compareTo(Double anotherDouble) {
1001 return Double.compare(value, anotherDouble.value);
1002 }
1003
1004 /**
1005 * Compares the two specified {@code double} values. The sign
1006 * of the integer value returned is the same as that of the
1007 * integer that would be returned by the call:
1008 * <pre>
1009 * new Double(d1).compareTo(new Double(d2))
1010 * </pre>
1011 *
1012 * @param d1 the first {@code double} to compare
1013 * @param d2 the second {@code double} to compare
1014 * @return the value {@code 0} if {@code d1} is
1015 * numerically equal to {@code d2}; a value less than
1016 * {@code 0} if {@code d1} is numerically less than
1017 * {@code d2}; and a value greater than {@code 0}
1018 * if {@code d1} is numerically greater than
1019 * {@code d2}.
1020 * @since 1.4
1021 */
1022 public static int compare(double d1, double d2) {
1023 if (d1 < d2)
1024 return -1; // Neither val is NaN, thisVal is smaller
1025 if (d1 > d2)
1026 return 1; // Neither val is NaN, thisVal is larger
1027
1028 // Cannot use doubleToRawLongBits because of possibility of NaNs.
1029 long thisBits = Double.doubleToLongBits(d1);
1030 long anotherBits = Double.doubleToLongBits(d2);
1031
1032 return (thisBits == anotherBits ? 0 : // Values are equal
1033 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1034 1)); // (0.0, -0.0) or (NaN, !NaN)
1035 }
1036
1037 /**
1038 * Adds two {@code double} values together as per the + operator.
1039 *
1040 * @param a the first operand
1041 * @param b the second operand
1042 * @return the sum of {@code a} and {@code b}
1043 * @jls 4.2.4 Floating-Point Operations
1044 * @see java.util.function.BinaryOperator
1045 * @since 1.8
1046 */
1047 public static double sum(double a, double b) {
1048 return a + b;
1049 }
1050
1051 /**
1052 * Returns the greater of two {@code double} values
1053 * as if by calling {@link Math#max(double, double) Math.max}.
1054 *
1055 * @param a the first operand
1056 * @param b the second operand
1057 * @return the greater of {@code a} and {@code b}
1058 * @see java.util.function.BinaryOperator
1059 * @since 1.8
1060 */
1061 public static double max(double a, double b) {
1062 return Math.max(a, b);
1063 }
1064
1065 /**
1066 * Returns the smaller of two {@code double} values
1067 * as if by calling {@link Math#min(double, double) Math.min}.
1068 *
1069 * @param a the first operand
1070 * @param b the second operand
1071 * @return the smaller of {@code a} and {@code b}.
1072 * @see java.util.function.BinaryOperator
1073 * @since 1.8
1074 */
1075 public static double min(double a, double b) {
1076 return Math.min(a, b);
1077 }
1078
1079 /**
1080 * Returns an {@link Optional} containing the nominal descriptor for this
1081 * instance, which is the instance itself.
1082 *
1083 * @return an {@link Optional} describing the {@linkplain Double} instance
1084 * @since 12
1085 */
1086 @Override
1087 public Optional<Double> describeConstable() {
1088 return Optional.of(this);
1089 }
1090
1091 /**
1092 * Resolves this instance as a {@link ConstantDesc}, the result of which is
1093 * the instance itself.
1094 *
1095 * @param lookup ignored
1096 * @return the {@linkplain Double} instance
1097 * @since 12
1098 */
1099 @Override
1100 public Double resolveConstantDesc(MethodHandles.Lookup lookup) {
1101 return this;
1102 }
1103
1104 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1105 @java.io.Serial
1106 private static final long serialVersionUID = -9172774392245257468L;
1107 }