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 }