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 }