1 /*
2 * Copyright (c) 1994, 2016, 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.math.FloatingDecimal;
29 import jdk.internal.math.DoubleConsts;
30 import jdk.internal.HotSpotIntrinsicCandidate;
31
32 /**
33 * The {@code Double} class wraps a value of the primitive type
34 * {@code double} in an object. An object of type
35 * {@code Double} contains a single field whose type is
36 * {@code double}.
37 *
38 * <p>In addition, this class provides several methods for converting a
39 * {@code double} to a {@code String} and a
40 * {@code String} to a {@code double}, as well as other
41 * constants and methods useful when dealing with a
42 * {@code double}.
43 *
44 * @author Lee Boynton
45 * @author Arthur van Hoff
46 * @author Joseph D. Darcy
47 * @since 1.0
48 */
49 public final class Double extends Number implements Comparable<Double> {
50 /**
51 * A constant holding the positive infinity of type
52 * {@code double}. It is equal to the value returned by
53 * {@code Double.longBitsToDouble(0x7ff0000000000000L)}.
54 */
55 public static final double POSITIVE_INFINITY = 1.0 / 0.0;
56
57 /**
58 * A constant holding the negative infinity of type
59 * {@code double}. It is equal to the value returned by
60 * {@code Double.longBitsToDouble(0xfff0000000000000L)}.
61 */
62 public static final double NEGATIVE_INFINITY = -1.0 / 0.0;
63
64 /**
65 * A constant holding a Not-a-Number (NaN) value of type
66 * {@code double}. It is equivalent to the value returned by
67 * {@code Double.longBitsToDouble(0x7ff8000000000000L)}.
68 */
69 public static final double NaN = 0.0d / 0.0;
70
71 /**
72 * A constant holding the largest positive finite value of type
73 * {@code double},
74 * (2-2<sup>-52</sup>)·2<sup>1023</sup>. It is equal to
75 * the hexadecimal floating-point literal
76 * {@code 0x1.fffffffffffffP+1023} and also equal to
77 * {@code Double.longBitsToDouble(0x7fefffffffffffffL)}.
78 */
79 public static final double MAX_VALUE = 0x1.fffffffffffffP+1023; // 1.7976931348623157e+308
80
81 /**
82 * A constant holding the smallest positive normal value of type
83 * {@code double}, 2<sup>-1022</sup>. It is equal to the
84 * hexadecimal floating-point literal {@code 0x1.0p-1022} and also
85 * equal to {@code Double.longBitsToDouble(0x0010000000000000L)}.
86 *
87 * @since 1.6
88 */
89 public static final double MIN_NORMAL = 0x1.0p-1022; // 2.2250738585072014E-308
90
91 /**
92 * A constant holding the smallest positive nonzero value of type
93 * {@code double}, 2<sup>-1074</sup>. It is equal to the
94 * hexadecimal floating-point literal
95 * {@code 0x0.0000000000001P-1022} and also equal to
96 * {@code Double.longBitsToDouble(0x1L)}.
97 */
98 public static final double MIN_VALUE = 0x0.0000000000001P-1022; // 4.9e-324
99
100 /**
101 * Maximum exponent a finite {@code double} variable may have.
102 * It is equal to the value returned by
103 * {@code Math.getExponent(Double.MAX_VALUE)}.
104 *
105 * @since 1.6
106 */
107 public static final int MAX_EXPONENT = 1023;
108
109 /**
110 * Minimum exponent a normalized {@code double} variable may
111 * have. It is equal to the value returned by
112 * {@code Math.getExponent(Double.MIN_NORMAL)}.
113 *
114 * @since 1.6
115 */
116 public static final int MIN_EXPONENT = -1022;
117
118 /**
119 * The number of bits used to represent a {@code double} value.
120 *
121 * @since 1.5
122 */
123 public static final int SIZE = 64;
124
125 /**
126 * The number of bytes used to represent a {@code double} value.
127 *
128 * @since 1.8
129 */
130 public static final int BYTES = SIZE / Byte.SIZE;
131
132 /**
133 * The {@code Class} instance representing the primitive type
134 * {@code double}.
135 *
136 * @since 1.1
137 */
138 @SuppressWarnings("unchecked")
139 public static final Class<Double> TYPE = (Class<Double>) Class.getPrimitiveClass("double");
140
141 /**
142 * Returns a string representation of the {@code double}
143 * argument. All characters mentioned below are ASCII characters.
144 * <ul>
145 * <li>If the argument is NaN, the result is the string
146 * "{@code NaN}".
147 * <li>Otherwise, the result is a string that represents the sign and
148 * magnitude (absolute value) of the argument. If the sign is negative,
149 * the first character of the result is '{@code -}'
150 * ({@code '\u005Cu002D'}); if the sign is positive, no sign character
151 * appears in the result. As for the magnitude <i>m</i>:
152 * <ul>
153 * <li>If <i>m</i> is infinity, it is represented by the characters
154 * {@code "Infinity"}; thus, positive infinity produces the result
155 * {@code "Infinity"} and negative infinity produces the result
156 * {@code "-Infinity"}.
157 *
158 * <li>If <i>m</i> is zero, it is represented by the characters
159 * {@code "0.0"}; thus, negative zero produces the result
160 * {@code "-0.0"} and positive zero produces the result
161 * {@code "0.0"}.
162 *
163 * <li>If <i>m</i> is greater than or equal to 10<sup>-3</sup> but less
164 * than 10<sup>7</sup>, then it is represented as the integer part of
165 * <i>m</i>, in decimal form with no leading zeroes, followed by
166 * '{@code .}' ({@code '\u005Cu002E'}), followed by one or
167 * more decimal digits representing the fractional part of <i>m</i>.
168 *
169 * <li>If <i>m</i> is less than 10<sup>-3</sup> or greater than or
170 * equal to 10<sup>7</sup>, then it is represented in so-called
171 * "computerized scientific notation." Let <i>n</i> be the unique
172 * integer such that 10<sup><i>n</i></sup> ≤ <i>m</i> {@literal <}
173 * 10<sup><i>n</i>+1</sup>; then let <i>a</i> be the
174 * mathematically exact quotient of <i>m</i> and
175 * 10<sup><i>n</i></sup> so that 1 ≤ <i>a</i> {@literal <} 10. The
176 * magnitude is then represented as the integer part of <i>a</i>,
177 * as a single decimal digit, followed by '{@code .}'
178 * ({@code '\u005Cu002E'}), followed by decimal digits
179 * representing the fractional part of <i>a</i>, followed by the
180 * letter '{@code E}' ({@code '\u005Cu0045'}), followed
181 * by a representation of <i>n</i> as a decimal integer, as
182 * produced by the method {@link Integer#toString(int)}.
183 * </ul>
184 * </ul>
185 * How many digits must be printed for the fractional part of
186 * <i>m</i> or <i>a</i>? There must be at least one digit to represent
187 * the fractional part, and beyond that as many, but only as many, more
188 * digits as are needed to uniquely distinguish the argument value from
189 * adjacent values of type {@code double}. That is, suppose that
190 * <i>x</i> is the exact mathematical value represented by the decimal
191 * representation produced by this method for a finite nonzero argument
192 * <i>d</i>. Then <i>d</i> must be the {@code double} value nearest
193 * to <i>x</i>; or if two {@code double} values are equally close
194 * to <i>x</i>, then <i>d</i> must be one of them and the least
195 * significant bit of the significand of <i>d</i> must be {@code 0}.
196 *
197 * <p>To create localized string representations of a floating-point
198 * value, use subclasses of {@link java.text.NumberFormat}.
199 *
200 * @param d the {@code double} to be converted.
201 * @return a string representation of the argument.
202 */
203 public static String toString(double d) {
204 return FloatingDecimal.toJavaFormatString(d);
205 }
206
207 /**
208 * Returns a hexadecimal string representation of the
209 * {@code double} argument. All characters mentioned below
210 * are ASCII characters.
211 *
212 * <ul>
213 * <li>If the argument is NaN, the result is the string
214 * "{@code NaN}".
215 * <li>Otherwise, the result is a string that represents the sign
216 * and magnitude of the argument. If the sign is negative, the
217 * first character of the result is '{@code -}'
218 * ({@code '\u005Cu002D'}); if the sign is positive, no sign
219 * character appears in the result. As for the magnitude <i>m</i>:
220 *
221 * <ul>
222 * <li>If <i>m</i> is infinity, it is represented by the string
223 * {@code "Infinity"}; thus, positive infinity produces the
224 * result {@code "Infinity"} and negative infinity produces
225 * the result {@code "-Infinity"}.
226 *
227 * <li>If <i>m</i> is zero, it is represented by the string
228 * {@code "0x0.0p0"}; thus, negative zero produces the result
229 * {@code "-0x0.0p0"} and positive zero produces the result
230 * {@code "0x0.0p0"}.
231 *
232 * <li>If <i>m</i> is a {@code double} value with a
233 * normalized representation, substrings are used to represent the
234 * significand and exponent fields. The significand is
235 * represented by the characters {@code "0x1."}
236 * followed by a lowercase hexadecimal representation of the rest
237 * of the significand as a fraction. Trailing zeros in the
238 * hexadecimal representation are removed unless all the digits
239 * are zero, in which case a single zero is used. Next, the
240 * exponent is represented by {@code "p"} followed
241 * by a decimal string of the unbiased exponent as if produced by
242 * a call to {@link Integer#toString(int) Integer.toString} on the
243 * exponent value.
244 *
245 * <li>If <i>m</i> is a {@code double} value with a subnormal
246 * representation, the significand is represented by the
247 * characters {@code "0x0."} followed by a
248 * hexadecimal representation of the rest of the significand as a
249 * fraction. Trailing zeros in the hexadecimal representation are
250 * removed. Next, the exponent is represented by
251 * {@code "p-1022"}. Note that there must be at
252 * least one nonzero digit in a subnormal significand.
253 *
254 * </ul>
255 *
256 * </ul>
257 *
258 * <table class="plain">
259 * <caption>Examples</caption>
260 * <thead>
261 * <tr><th>Floating-point Value</th><th>Hexadecimal String</th>
262 * </thead>
263 * <tbody>
264 * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td>
265 * <tr><td>{@code -1.0}</td> <td>{@code -0x1.0p0}</td>
266 * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td>
267 * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td>
268 * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td>
269 * <tr><td>{@code 0.25}</td> <td>{@code 0x1.0p-2}</td>
270 * <tr><td>{@code Double.MAX_VALUE}</td>
271 * <td>{@code 0x1.fffffffffffffp1023}</td>
272 * <tr><td>{@code Minimum Normal Value}</td>
273 * <td>{@code 0x1.0p-1022}</td>
274 * <tr><td>{@code Maximum Subnormal Value}</td>
275 * <td>{@code 0x0.fffffffffffffp-1022}</td>
276 * <tr><td>{@code Double.MIN_VALUE}</td>
277 * <td>{@code 0x0.0000000000001p-1022}</td>
278 * </tbody>
279 * </table>
280 * @param d the {@code double} to be converted.
281 * @return a hex string representation of the argument.
282 * @since 1.5
283 * @author Joseph D. Darcy
284 */
285 public static String toHexString(double d) {
286 /*
287 * Modeled after the "a" conversion specifier in C99, section
288 * 7.19.6.1; however, the output of this method is more
289 * tightly specified.
290 */
291 if (!isFinite(d) )
292 // For infinity and NaN, use the decimal output.
293 return Double.toString(d);
294 else {
295 // Initialized to maximum size of output.
296 StringBuilder answer = new StringBuilder(24);
297
298 if (Math.copySign(1.0, d) == -1.0) // value is negative,
299 answer.append("-"); // so append sign info
300
301 answer.append("0x");
302
303 d = Math.abs(d);
304
305 if(d == 0.0) {
306 answer.append("0.0p0");
307 } else {
308 boolean subnormal = (d < Double.MIN_NORMAL);
309
310 // Isolate significand bits and OR in a high-order bit
311 // so that the string representation has a known
312 // length.
313 long signifBits = (Double.doubleToLongBits(d)
314 & DoubleConsts.SIGNIF_BIT_MASK) |
315 0x1000000000000000L;
316
317 // Subnormal values have a 0 implicit bit; normal
318 // values have a 1 implicit bit.
319 answer.append(subnormal ? "0." : "1.");
320
321 // Isolate the low-order 13 digits of the hex
322 // representation. If all the digits are zero,
323 // replace with a single 0; otherwise, remove all
324 // trailing zeros.
325 String signif = Long.toHexString(signifBits).substring(3,16);
326 answer.append(signif.equals("0000000000000") ? // 13 zeros
327 "0":
328 signif.replaceFirst("0{1,12}$", ""));
329
330 answer.append('p');
331 // If the value is subnormal, use the E_min exponent
332 // value for double; otherwise, extract and report d's
333 // exponent (the representation of a subnormal uses
334 // E_min -1).
335 answer.append(subnormal ?
336 Double.MIN_EXPONENT:
337 Math.getExponent(d));
338 }
339 return answer.toString();
340 }
341 }
342
343 /**
344 * Returns a {@code Double} object holding the
345 * {@code double} value represented by the argument string
346 * {@code s}.
347 *
348 * <p>If {@code s} is {@code null}, then a
349 * {@code NullPointerException} is thrown.
350 *
351 * <p>Leading and trailing whitespace characters in {@code s}
352 * are ignored. Whitespace is removed as if by the {@link
353 * String#trim} method; that is, both ASCII space and control
354 * characters are removed. The rest of {@code s} should
355 * constitute a <i>FloatValue</i> as described by the lexical
356 * syntax rules:
357 *
358 * <blockquote>
359 * <dl>
360 * <dt><i>FloatValue:</i>
361 * <dd><i>Sign<sub>opt</sub></i> {@code NaN}
362 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity}
363 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i>
364 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i>
365 * <dd><i>SignedInteger</i>
366 * </dl>
367 *
368 * <dl>
369 * <dt><i>HexFloatingPointLiteral</i>:
370 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i>
371 * </dl>
372 *
373 * <dl>
374 * <dt><i>HexSignificand:</i>
375 * <dd><i>HexNumeral</i>
376 * <dd><i>HexNumeral</i> {@code .}
377 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub>
378 * </i>{@code .}<i> HexDigits</i>
379 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub>
380 * </i>{@code .} <i>HexDigits</i>
381 * </dl>
382 *
383 * <dl>
384 * <dt><i>BinaryExponent:</i>
385 * <dd><i>BinaryExponentIndicator SignedInteger</i>
386 * </dl>
387 *
388 * <dl>
389 * <dt><i>BinaryExponentIndicator:</i>
390 * <dd>{@code p}
391 * <dd>{@code P}
392 * </dl>
393 *
394 * </blockquote>
395 *
396 * where <i>Sign</i>, <i>FloatingPointLiteral</i>,
397 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and
398 * <i>FloatTypeSuffix</i> are as defined in the lexical structure
399 * sections of
400 * <cite>The Java™ Language Specification</cite>,
401 * except that underscores are not accepted between digits.
402 * If {@code s} does not have the form of
403 * a <i>FloatValue</i>, then a {@code NumberFormatException}
404 * is thrown. Otherwise, {@code s} is regarded as
405 * representing an exact decimal value in the usual
406 * "computerized scientific notation" or as an exact
407 * hexadecimal value; this exact numerical value is then
408 * conceptually converted to an "infinitely precise"
409 * binary value that is then rounded to type {@code double}
410 * by the usual round-to-nearest rule of IEEE 754 floating-point
411 * arithmetic, which includes preserving the sign of a zero
412 * value.
413 *
414 * Note that the round-to-nearest rule also implies overflow and
415 * underflow behaviour; if the exact value of {@code s} is large
416 * enough in magnitude (greater than or equal to ({@link
417 * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2),
418 * rounding to {@code double} will result in an infinity and if the
419 * exact value of {@code s} is small enough in magnitude (less
420 * than or equal to {@link #MIN_VALUE}/2), rounding to float will
421 * result in a zero.
422 *
423 * Finally, after rounding a {@code Double} object representing
424 * this {@code double} value is returned.
425 *
426 * <p> To interpret localized string representations of a
427 * floating-point value, use subclasses of {@link
428 * java.text.NumberFormat}.
429 *
430 * <p>Note that trailing format specifiers, specifiers that
431 * determine the type of a floating-point literal
432 * ({@code 1.0f} is a {@code float} value;
433 * {@code 1.0d} is a {@code double} value), do
434 * <em>not</em> influence the results of this method. In other
435 * words, the numerical value of the input string is converted
436 * directly to the target floating-point type. The two-step
437 * sequence of conversions, string to {@code float} followed
438 * by {@code float} to {@code double}, is <em>not</em>
439 * equivalent to converting a string directly to
440 * {@code double}. For example, the {@code float}
441 * literal {@code 0.1f} is equal to the {@code double}
442 * value {@code 0.10000000149011612}; the {@code float}
443 * literal {@code 0.1f} represents a different numerical
444 * value than the {@code double} literal
445 * {@code 0.1}. (The numerical value 0.1 cannot be exactly
446 * represented in a binary floating-point number.)
447 *
448 * <p>To avoid calling this method on an invalid string and having
449 * a {@code NumberFormatException} be thrown, the regular
450 * expression below can be used to screen the input string:
451 *
452 * <pre>{@code
453 * final String Digits = "(\\p{Digit}+)";
454 * final String HexDigits = "(\\p{XDigit}+)";
455 * // an exponent is 'e' or 'E' followed by an optionally
456 * // signed decimal integer.
457 * final String Exp = "[eE][+-]?"+Digits;
458 * final String fpRegex =
459 * ("[\\x00-\\x20]*"+ // Optional leading "whitespace"
460 * "[+-]?(" + // Optional sign character
461 * "NaN|" + // "NaN" string
462 * "Infinity|" + // "Infinity" string
463 *
464 * // A decimal floating-point string representing a finite positive
465 * // number without a leading sign has at most five basic pieces:
466 * // Digits . Digits ExponentPart FloatTypeSuffix
467 * //
468 * // Since this method allows integer-only strings as input
469 * // in addition to strings of floating-point literals, the
470 * // two sub-patterns below are simplifications of the grammar
471 * // productions from section 3.10.2 of
472 * // The Java Language Specification.
473 *
474 * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt
475 * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+
476 *
477 * // . Digits ExponentPart_opt FloatTypeSuffix_opt
478 * "(\\.("+Digits+")("+Exp+")?)|"+
479 *
480 * // Hexadecimal strings
481 * "((" +
482 * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt
483 * "(0[xX]" + HexDigits + "(\\.)?)|" +
484 *
485 * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt
486 * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" +
487 *
488 * ")[pP][+-]?" + Digits + "))" +
489 * "[fFdD]?))" +
490 * "[\\x00-\\x20]*");// Optional trailing "whitespace"
491 *
492 * if (Pattern.matches(fpRegex, myString))
493 * Double.valueOf(myString); // Will not throw NumberFormatException
494 * else {
495 * // Perform suitable alternative action
496 * }
497 * }</pre>
498 *
499 * @param s the string to be parsed.
500 * @return a {@code Double} object holding the value
501 * represented by the {@code String} argument.
502 * @throws NumberFormatException if the string does not contain a
503 * parsable number.
504 */
505 public static Double valueOf(String s) throws NumberFormatException {
506 return new Double(parseDouble(s));
507 }
508
509 /**
510 * Returns a {@code Double} instance representing the specified
511 * {@code double} value.
512 * If a new {@code Double} instance is not required, this method
513 * should generally be used in preference to the constructor
514 * {@link #Double(double)}, as this method is likely to yield
515 * significantly better space and time performance by caching
516 * frequently requested values.
517 *
518 * @param d a double value.
519 * @return a {@code Double} instance representing {@code d}.
520 * @since 1.5
521 */
522 @HotSpotIntrinsicCandidate
523 public static Double valueOf(double d) {
524 return new Double(d);
525 }
526
527 /**
528 * Returns a new {@code double} initialized to the value
529 * represented by the specified {@code String}, as performed
530 * by the {@code valueOf} method of class
531 * {@code Double}.
532 *
533 * @param s the string to be parsed.
534 * @return the {@code double} value represented by the string
535 * argument.
536 * @throws NullPointerException if the string is null
537 * @throws NumberFormatException if the string does not contain
538 * a parsable {@code double}.
539 * @see java.lang.Double#valueOf(String)
540 * @since 1.2
541 */
542 public static double parseDouble(String s) throws NumberFormatException {
543 return FloatingDecimal.parseDouble(s);
544 }
545
546 /**
547 * Returns {@code true} if the specified number is a
548 * Not-a-Number (NaN) value, {@code false} otherwise.
549 *
550 * @param v the value to be tested.
551 * @return {@code true} if the value of the argument is NaN;
552 * {@code false} otherwise.
553 */
554 public static boolean isNaN(double v) {
555 return (v != v);
556 }
557
558 /**
559 * Returns {@code true} if the specified number is infinitely
560 * large in magnitude, {@code false} otherwise.
561 *
562 * @param v the value to be tested.
563 * @return {@code true} if the value of the argument is positive
564 * infinity or negative infinity; {@code false} otherwise.
565 */
566 public static boolean isInfinite(double v) {
567 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY);
568 }
569
570 /**
571 * Returns {@code true} if the argument is a finite floating-point
572 * value; returns {@code false} otherwise (for NaN and infinity
573 * arguments).
574 *
575 * @param d the {@code double} value to be tested
576 * @return {@code true} if the argument is a finite
577 * floating-point value, {@code false} otherwise.
578 * @since 1.8
579 */
580 public static boolean isFinite(double d) {
581 return Math.abs(d) <= Double.MAX_VALUE;
582 }
583
584 /**
585 * The value of the Double.
586 *
587 * @serial
588 */
589 private final double value;
590
591 /**
592 * Constructs a newly allocated {@code Double} object that
593 * represents the primitive {@code double} argument.
594 *
595 * @param value the value to be represented by the {@code Double}.
596 *
597 * @deprecated
598 * It is rarely appropriate to use this constructor. The static factory
599 * {@link #valueOf(double)} is generally a better choice, as it is
600 * likely to yield significantly better space and time performance.
601 */
602 @Deprecated(since="9")
603 public Double(double value) {
604 this.value = value;
605 }
606
607 /**
608 * Constructs a newly allocated {@code Double} object that
609 * represents the floating-point value of type {@code double}
610 * represented by the string. The string is converted to a
611 * {@code double} value as if by the {@code valueOf} method.
612 *
613 * @param s a string to be converted to a {@code Double}.
614 * @throws NumberFormatException if the string does not contain a
615 * parsable number.
616 *
617 * @deprecated
618 * It is rarely appropriate to use this constructor.
619 * Use {@link #parseDouble(String)} to convert a string to a
620 * {@code double} primitive, or use {@link #valueOf(String)}
621 * to convert a string to a {@code Double} object.
622 */
623 @Deprecated(since="9")
624 public Double(String s) throws NumberFormatException {
625 value = parseDouble(s);
626 }
627
628 /**
629 * Returns {@code true} if this {@code Double} value is
630 * a Not-a-Number (NaN), {@code false} otherwise.
631 *
632 * @return {@code true} if the value represented by this object is
633 * NaN; {@code false} otherwise.
634 */
635 public boolean isNaN() {
636 return isNaN(value);
637 }
638
639 /**
640 * Returns {@code true} if this {@code Double} value is
641 * infinitely large in magnitude, {@code false} otherwise.
642 *
643 * @return {@code true} if the value represented by this object is
644 * positive infinity or negative infinity;
645 * {@code false} otherwise.
646 */
647 public boolean isInfinite() {
648 return isInfinite(value);
649 }
650
651 /**
652 * Returns a string representation of this {@code Double} object.
653 * The primitive {@code double} value represented by this
654 * object is converted to a string exactly as if by the method
655 * {@code toString} of one argument.
656 *
657 * @return a {@code String} representation of this object.
658 * @see java.lang.Double#toString(double)
659 */
660 public String toString() {
661 return toString(value);
662 }
663
664 /**
665 * Returns the value of this {@code Double} as a {@code byte}
666 * after a narrowing primitive conversion.
667 *
668 * @return the {@code double} value represented by this object
669 * converted to type {@code byte}
670 * @jls 5.1.3 Narrowing Primitive Conversions
671 * @since 1.1
672 */
673 public byte byteValue() {
674 return (byte)value;
675 }
676
677 /**
678 * Returns the value of this {@code Double} as a {@code short}
679 * after a narrowing primitive conversion.
680 *
681 * @return the {@code double} value represented by this object
682 * converted to type {@code short}
683 * @jls 5.1.3 Narrowing Primitive Conversions
684 * @since 1.1
685 */
686 public short shortValue() {
687 return (short)value;
688 }
689
690 /**
691 * Returns the value of this {@code Double} as an {@code int}
692 * after a narrowing primitive conversion.
693 * @jls 5.1.3 Narrowing Primitive Conversions
694 *
695 * @return the {@code double} value represented by this object
696 * converted to type {@code int}
697 */
698 public int intValue() {
699 return (int)value;
700 }
701
702 /**
703 * Returns the value of this {@code Double} as a {@code long}
704 * after a narrowing primitive conversion.
705 *
706 * @return the {@code double} value represented by this object
707 * converted to type {@code long}
708 * @jls 5.1.3 Narrowing Primitive Conversions
709 */
710 public long longValue() {
711 return (long)value;
712 }
713
714 /**
715 * Returns the value of this {@code Double} as a {@code float}
716 * after a narrowing primitive conversion.
717 *
718 * @return the {@code double} value represented by this object
719 * converted to type {@code float}
720 * @jls 5.1.3 Narrowing Primitive Conversions
721 * @since 1.0
722 */
723 public float floatValue() {
724 return (float)value;
725 }
726
727 /**
728 * Returns the {@code double} value of this {@code Double} object.
729 *
730 * @return the {@code double} value represented by this object
731 */
732 @HotSpotIntrinsicCandidate
733 public double doubleValue() {
734 return value;
735 }
736
737 /**
738 * Returns a hash code for this {@code Double} object. The
739 * result is the exclusive OR of the two halves of the
740 * {@code long} integer bit representation, exactly as
741 * produced by the method {@link #doubleToLongBits(double)}, of
742 * the primitive {@code double} value represented by this
743 * {@code Double} object. That is, the hash code is the value
744 * of the expression:
745 *
746 * <blockquote>
747 * {@code (int)(v^(v>>>32))}
748 * </blockquote>
749 *
750 * where {@code v} is defined by:
751 *
752 * <blockquote>
753 * {@code long v = Double.doubleToLongBits(this.doubleValue());}
754 * </blockquote>
755 *
756 * @return a {@code hash code} value for this object.
757 */
758 @Override
759 public int hashCode() {
760 return Double.hashCode(value);
761 }
762
763 /**
764 * Returns a hash code for a {@code double} value; compatible with
765 * {@code Double.hashCode()}.
766 *
767 * @param value the value to hash
768 * @return a hash code value for a {@code double} value.
769 * @since 1.8
770 */
771 public static int hashCode(double value) {
772 long bits = doubleToLongBits(value);
773 return (int)(bits ^ (bits >>> 32));
774 }
775
776 /**
777 * Compares this object against the specified object. The result
778 * is {@code true} if and only if the argument is not
779 * {@code null} and is a {@code Double} object that
780 * represents a {@code double} that has the same value as the
781 * {@code double} represented by this object. For this
782 * purpose, two {@code double} values are considered to be
783 * the same if and only if the method {@link
784 * #doubleToLongBits(double)} returns the identical
785 * {@code long} value when applied to each.
786 *
787 * <p>Note that in most cases, for two instances of class
788 * {@code Double}, {@code d1} and {@code d2}, the
789 * value of {@code d1.equals(d2)} is {@code true} if and
790 * only if
791 *
792 * <blockquote>
793 * {@code d1.doubleValue() == d2.doubleValue()}
794 * </blockquote>
795 *
796 * <p>also has the value {@code true}. However, there are two
797 * exceptions:
798 * <ul>
799 * <li>If {@code d1} and {@code d2} both represent
800 * {@code Double.NaN}, then the {@code equals} method
801 * returns {@code true}, even though
802 * {@code Double.NaN==Double.NaN} has the value
803 * {@code false}.
804 * <li>If {@code d1} represents {@code +0.0} while
805 * {@code d2} represents {@code -0.0}, or vice versa,
806 * the {@code equal} test has the value {@code false},
807 * even though {@code +0.0==-0.0} has the value {@code true}.
808 * </ul>
809 * This definition allows hash tables to operate properly.
810 * @param obj the object to compare with.
811 * @return {@code true} if the objects are the same;
812 * {@code false} otherwise.
813 * @see java.lang.Double#doubleToLongBits(double)
814 */
815 public boolean equals(Object obj) {
816 return (obj instanceof Double)
817 && (doubleToLongBits(((Double)obj).value) ==
818 doubleToLongBits(value));
819 }
820
821 /**
822 * Returns a representation of the specified floating-point value
823 * according to the IEEE 754 floating-point "double
824 * format" bit layout.
825 *
826 * <p>Bit 63 (the bit that is selected by the mask
827 * {@code 0x8000000000000000L}) represents the sign of the
828 * floating-point number. Bits
829 * 62-52 (the bits that are selected by the mask
830 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
831 * (the bits that are selected by the mask
832 * {@code 0x000fffffffffffffL}) represent the significand
833 * (sometimes called the mantissa) of the floating-point number.
834 *
835 * <p>If the argument is positive infinity, the result is
836 * {@code 0x7ff0000000000000L}.
837 *
838 * <p>If the argument is negative infinity, the result is
839 * {@code 0xfff0000000000000L}.
840 *
841 * <p>If the argument is NaN, the result is
842 * {@code 0x7ff8000000000000L}.
843 *
844 * <p>In all cases, the result is a {@code long} integer that, when
845 * given to the {@link #longBitsToDouble(long)} method, will produce a
846 * floating-point value the same as the argument to
847 * {@code doubleToLongBits} (except all NaN values are
848 * collapsed to a single "canonical" NaN value).
849 *
850 * @param value a {@code double} precision floating-point number.
851 * @return the bits that represent the floating-point number.
852 */
853 @HotSpotIntrinsicCandidate
854 public static long doubleToLongBits(double value) {
855 if (!isNaN(value)) {
856 return doubleToRawLongBits(value);
857 }
858 return 0x7ff8000000000000L;
859 }
860
861 /**
862 * Returns a representation of the specified floating-point value
863 * according to the IEEE 754 floating-point "double
864 * format" bit layout, preserving Not-a-Number (NaN) values.
865 *
866 * <p>Bit 63 (the bit that is selected by the mask
867 * {@code 0x8000000000000000L}) represents the sign of the
868 * floating-point number. Bits
869 * 62-52 (the bits that are selected by the mask
870 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0
871 * (the bits that are selected by the mask
872 * {@code 0x000fffffffffffffL}) represent the significand
873 * (sometimes called the mantissa) of the floating-point number.
874 *
875 * <p>If the argument is positive infinity, the result is
876 * {@code 0x7ff0000000000000L}.
877 *
878 * <p>If the argument is negative infinity, the result is
879 * {@code 0xfff0000000000000L}.
880 *
881 * <p>If the argument is NaN, the result is the {@code long}
882 * integer representing the actual NaN value. Unlike the
883 * {@code doubleToLongBits} method,
884 * {@code doubleToRawLongBits} does not collapse all the bit
885 * patterns encoding a NaN to a single "canonical" NaN
886 * value.
887 *
888 * <p>In all cases, the result is a {@code long} integer that,
889 * when given to the {@link #longBitsToDouble(long)} method, will
890 * produce a floating-point value the same as the argument to
891 * {@code doubleToRawLongBits}.
892 *
893 * @param value a {@code double} precision floating-point number.
894 * @return the bits that represent the floating-point number.
895 * @since 1.3
896 */
897 @HotSpotIntrinsicCandidate
898 public static native long doubleToRawLongBits(double value);
899
900 /**
901 * Returns the {@code double} value corresponding to a given
902 * bit representation.
903 * The argument is considered to be a representation of a
904 * floating-point value according to the IEEE 754 floating-point
905 * "double format" bit layout.
906 *
907 * <p>If the argument is {@code 0x7ff0000000000000L}, the result
908 * is positive infinity.
909 *
910 * <p>If the argument is {@code 0xfff0000000000000L}, the result
911 * is negative infinity.
912 *
913 * <p>If the argument is any value in the range
914 * {@code 0x7ff0000000000001L} through
915 * {@code 0x7fffffffffffffffL} or in the range
916 * {@code 0xfff0000000000001L} through
917 * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE
918 * 754 floating-point operation provided by Java can distinguish
919 * between two NaN values of the same type with different bit
920 * patterns. Distinct values of NaN are only distinguishable by
921 * use of the {@code Double.doubleToRawLongBits} method.
922 *
923 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three
924 * values that can be computed from the argument:
925 *
926 * <blockquote><pre>{@code
927 * int s = ((bits >> 63) == 0) ? 1 : -1;
928 * int e = (int)((bits >> 52) & 0x7ffL);
929 * long m = (e == 0) ?
930 * (bits & 0xfffffffffffffL) << 1 :
931 * (bits & 0xfffffffffffffL) | 0x10000000000000L;
932 * }</pre></blockquote>
933 *
934 * Then the floating-point result equals the value of the mathematical
935 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>.
936 *
937 * <p>Note that this method may not be able to return a
938 * {@code double} NaN with exactly same bit pattern as the
939 * {@code long} argument. IEEE 754 distinguishes between two
940 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The
941 * differences between the two kinds of NaN are generally not
942 * visible in Java. Arithmetic operations on signaling NaNs turn
943 * them into quiet NaNs with a different, but often similar, bit
944 * pattern. However, on some processors merely copying a
945 * signaling NaN also performs that conversion. In particular,
946 * copying a signaling NaN to return it to the calling method
947 * may perform this conversion. So {@code longBitsToDouble}
948 * may not be able to return a {@code double} with a
949 * signaling NaN bit pattern. Consequently, for some
950 * {@code long} values,
951 * {@code doubleToRawLongBits(longBitsToDouble(start))} may
952 * <i>not</i> equal {@code start}. Moreover, which
953 * particular bit patterns represent signaling NaNs is platform
954 * dependent; although all NaN bit patterns, quiet or signaling,
955 * must be in the NaN range identified above.
956 *
957 * @param bits any {@code long} integer.
958 * @return the {@code double} floating-point value with the same
959 * bit pattern.
960 */
961 @HotSpotIntrinsicCandidate
962 public static native double longBitsToDouble(long bits);
963
964 /**
965 * Compares two {@code Double} objects numerically. There
966 * are two ways in which comparisons performed by this method
967 * differ from those performed by the Java language numerical
968 * comparison operators ({@code <, <=, ==, >=, >})
969 * when applied to primitive {@code double} values:
970 * <ul><li>
971 * {@code Double.NaN} is considered by this method
972 * to be equal to itself and greater than all other
973 * {@code double} values (including
974 * {@code Double.POSITIVE_INFINITY}).
975 * <li>
976 * {@code 0.0d} is considered by this method to be greater
977 * than {@code -0.0d}.
978 * </ul>
979 * This ensures that the <i>natural ordering</i> of
980 * {@code Double} objects imposed by this method is <i>consistent
981 * with equals</i>.
982 *
983 * @param anotherDouble the {@code Double} to be compared.
984 * @return the value {@code 0} if {@code anotherDouble} is
985 * numerically equal to this {@code Double}; a value
986 * less than {@code 0} if this {@code Double}
987 * is numerically less than {@code anotherDouble};
988 * and a value greater than {@code 0} if this
989 * {@code Double} is numerically greater than
990 * {@code anotherDouble}.
991 *
992 * @since 1.2
993 */
994 public int compareTo(Double anotherDouble) {
995 return Double.compare(value, anotherDouble.value);
996 }
997
998 /**
999 * Compares the two specified {@code double} values. The sign
1000 * of the integer value returned is the same as that of the
1001 * integer that would be returned by the call:
1002 * <pre>
1003 * new Double(d1).compareTo(new Double(d2))
1004 * </pre>
1005 *
1006 * @param d1 the first {@code double} to compare
1007 * @param d2 the second {@code double} to compare
1008 * @return the value {@code 0} if {@code d1} is
1009 * numerically equal to {@code d2}; a value less than
1010 * {@code 0} if {@code d1} is numerically less than
1011 * {@code d2}; and a value greater than {@code 0}
1012 * if {@code d1} is numerically greater than
1013 * {@code d2}.
1014 * @since 1.4
1015 */
1016 public static int compare(double d1, double d2) {
1017 if (d1 < d2)
1018 return -1; // Neither val is NaN, thisVal is smaller
1019 if (d1 > d2)
1020 return 1; // Neither val is NaN, thisVal is larger
1021
1022 // Cannot use doubleToRawLongBits because of possibility of NaNs.
1023 long thisBits = Double.doubleToLongBits(d1);
1024 long anotherBits = Double.doubleToLongBits(d2);
1025
1026 return (thisBits == anotherBits ? 0 : // Values are equal
1027 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN)
1028 1)); // (0.0, -0.0) or (NaN, !NaN)
1029 }
1030
1031 /**
1032 * Adds two {@code double} values together as per the + operator.
1033 *
1034 * @param a the first operand
1035 * @param b the second operand
1036 * @return the sum of {@code a} and {@code b}
1037 * @jls 4.2.4 Floating-Point Operations
1038 * @see java.util.function.BinaryOperator
1039 * @since 1.8
1040 */
1041 public static double sum(double a, double b) {
1042 return a + b;
1043 }
1044
1045 /**
1046 * Returns the greater of two {@code double} values
1047 * as if by calling {@link Math#max(double, double) Math.max}.
1048 *
1049 * @param a the first operand
1050 * @param b the second operand
1051 * @return the greater of {@code a} and {@code b}
1052 * @see java.util.function.BinaryOperator
1053 * @since 1.8
1054 */
1055 public static double max(double a, double b) {
1056 return Math.max(a, b);
1057 }
1058
1059 /**
1060 * Returns the smaller of two {@code double} values
1061 * as if by calling {@link Math#min(double, double) Math.min}.
1062 *
1063 * @param a the first operand
1064 * @param b the second operand
1065 * @return the smaller of {@code a} and {@code b}.
1066 * @see java.util.function.BinaryOperator
1067 * @since 1.8
1068 */
1069 public static double min(double a, double b) {
1070 return Math.min(a, b);
1071 }
1072
1073 /** use serialVersionUID from JDK 1.0.2 for interoperability */
1074 private static final long serialVersionUID = -9172774392245257468L;
1075 }