1 /* 2 * Copyright (c) 1994, 2014, 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 sun.misc.FloatingDecimal; 29 import sun.misc.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 border> 259 * <caption>Examples</caption> 260 * <tr><th>Floating-point Value</th><th>Hexadecimal String</th> 261 * <tr><td>{@code 1.0}</td> <td>{@code 0x1.0p0}</td> 262 * <tr><td>{@code -1.0}</td> <td>{@code -0x1.0p0}</td> 263 * <tr><td>{@code 2.0}</td> <td>{@code 0x1.0p1}</td> 264 * <tr><td>{@code 3.0}</td> <td>{@code 0x1.8p1}</td> 265 * <tr><td>{@code 0.5}</td> <td>{@code 0x1.0p-1}</td> 266 * <tr><td>{@code 0.25}</td> <td>{@code 0x1.0p-2}</td> 267 * <tr><td>{@code Double.MAX_VALUE}</td> 268 * <td>{@code 0x1.fffffffffffffp1023}</td> 269 * <tr><td>{@code Minimum Normal Value}</td> 270 * <td>{@code 0x1.0p-1022}</td> 271 * <tr><td>{@code Maximum Subnormal Value}</td> 272 * <td>{@code 0x0.fffffffffffffp-1022}</td> 273 * <tr><td>{@code Double.MIN_VALUE}</td> 274 * <td>{@code 0x0.0000000000001p-1022}</td> 275 * </table> 276 * @param d the {@code double} to be converted. 277 * @return a hex string representation of the argument. 278 * @since 1.5 279 * @author Joseph D. Darcy 280 */ 281 public static String toHexString(double d) { 282 /* 283 * Modeled after the "a" conversion specifier in C99, section 284 * 7.19.6.1; however, the output of this method is more 285 * tightly specified. 286 */ 287 if (!isFinite(d) ) 288 // For infinity and NaN, use the decimal output. 289 return Double.toString(d); 290 else { 291 // Initialized to maximum size of output. 292 StringBuilder answer = new StringBuilder(24); 293 294 if (Math.copySign(1.0, d) == -1.0) // value is negative, 295 answer.append("-"); // so append sign info 296 297 answer.append("0x"); 298 299 d = Math.abs(d); 300 301 if(d == 0.0) { 302 answer.append("0.0p0"); 303 } else { 304 boolean subnormal = (d < DoubleConsts.MIN_NORMAL); 305 306 // Isolate significand bits and OR in a high-order bit 307 // so that the string representation has a known 308 // length. 309 long signifBits = (Double.doubleToLongBits(d) 310 & DoubleConsts.SIGNIF_BIT_MASK) | 311 0x1000000000000000L; 312 313 // Subnormal values have a 0 implicit bit; normal 314 // values have a 1 implicit bit. 315 answer.append(subnormal ? "0." : "1."); 316 317 // Isolate the low-order 13 digits of the hex 318 // representation. If all the digits are zero, 319 // replace with a single 0; otherwise, remove all 320 // trailing zeros. 321 String signif = Long.toHexString(signifBits).substring(3,16); 322 answer.append(signif.equals("0000000000000") ? // 13 zeros 323 "0": 324 signif.replaceFirst("0{1,12}$", "")); 325 326 answer.append('p'); 327 // If the value is subnormal, use the E_min exponent 328 // value for double; otherwise, extract and report d's 329 // exponent (the representation of a subnormal uses 330 // E_min -1). 331 answer.append(subnormal ? 332 DoubleConsts.MIN_EXPONENT: 333 Math.getExponent(d)); 334 } 335 return answer.toString(); 336 } 337 } 338 339 /** 340 * Returns a {@code Double} object holding the 341 * {@code double} value represented by the argument string 342 * {@code s}. 343 * 344 * <p>If {@code s} is {@code null}, then a 345 * {@code NullPointerException} is thrown. 346 * 347 * <p>Leading and trailing whitespace characters in {@code s} 348 * are ignored. Whitespace is removed as if by the {@link 349 * String#trim} method; that is, both ASCII space and control 350 * characters are removed. The rest of {@code s} should 351 * constitute a <i>FloatValue</i> as described by the lexical 352 * syntax rules: 353 * 354 * <blockquote> 355 * <dl> 356 * <dt><i>FloatValue:</i> 357 * <dd><i>Sign<sub>opt</sub></i> {@code NaN} 358 * <dd><i>Sign<sub>opt</sub></i> {@code Infinity} 359 * <dd><i>Sign<sub>opt</sub> FloatingPointLiteral</i> 360 * <dd><i>Sign<sub>opt</sub> HexFloatingPointLiteral</i> 361 * <dd><i>SignedInteger</i> 362 * </dl> 363 * 364 * <dl> 365 * <dt><i>HexFloatingPointLiteral</i>: 366 * <dd> <i>HexSignificand BinaryExponent FloatTypeSuffix<sub>opt</sub></i> 367 * </dl> 368 * 369 * <dl> 370 * <dt><i>HexSignificand:</i> 371 * <dd><i>HexNumeral</i> 372 * <dd><i>HexNumeral</i> {@code .} 373 * <dd>{@code 0x} <i>HexDigits<sub>opt</sub> 374 * </i>{@code .}<i> HexDigits</i> 375 * <dd>{@code 0X}<i> HexDigits<sub>opt</sub> 376 * </i>{@code .} <i>HexDigits</i> 377 * </dl> 378 * 379 * <dl> 380 * <dt><i>BinaryExponent:</i> 381 * <dd><i>BinaryExponentIndicator SignedInteger</i> 382 * </dl> 383 * 384 * <dl> 385 * <dt><i>BinaryExponentIndicator:</i> 386 * <dd>{@code p} 387 * <dd>{@code P} 388 * </dl> 389 * 390 * </blockquote> 391 * 392 * where <i>Sign</i>, <i>FloatingPointLiteral</i>, 393 * <i>HexNumeral</i>, <i>HexDigits</i>, <i>SignedInteger</i> and 394 * <i>FloatTypeSuffix</i> are as defined in the lexical structure 395 * sections of 396 * <cite>The Java™ Language Specification</cite>, 397 * except that underscores are not accepted between digits. 398 * If {@code s} does not have the form of 399 * a <i>FloatValue</i>, then a {@code NumberFormatException} 400 * is thrown. Otherwise, {@code s} is regarded as 401 * representing an exact decimal value in the usual 402 * "computerized scientific notation" or as an exact 403 * hexadecimal value; this exact numerical value is then 404 * conceptually converted to an "infinitely precise" 405 * binary value that is then rounded to type {@code double} 406 * by the usual round-to-nearest rule of IEEE 754 floating-point 407 * arithmetic, which includes preserving the sign of a zero 408 * value. 409 * 410 * Note that the round-to-nearest rule also implies overflow and 411 * underflow behaviour; if the exact value of {@code s} is large 412 * enough in magnitude (greater than or equal to ({@link 413 * #MAX_VALUE} + {@link Math#ulp(double) ulp(MAX_VALUE)}/2), 414 * rounding to {@code double} will result in an infinity and if the 415 * exact value of {@code s} is small enough in magnitude (less 416 * than or equal to {@link #MIN_VALUE}/2), rounding to float will 417 * result in a zero. 418 * 419 * Finally, after rounding a {@code Double} object representing 420 * this {@code double} value is returned. 421 * 422 * <p> To interpret localized string representations of a 423 * floating-point value, use subclasses of {@link 424 * java.text.NumberFormat}. 425 * 426 * <p>Note that trailing format specifiers, specifiers that 427 * determine the type of a floating-point literal 428 * ({@code 1.0f} is a {@code float} value; 429 * {@code 1.0d} is a {@code double} value), do 430 * <em>not</em> influence the results of this method. In other 431 * words, the numerical value of the input string is converted 432 * directly to the target floating-point type. The two-step 433 * sequence of conversions, string to {@code float} followed 434 * by {@code float} to {@code double}, is <em>not</em> 435 * equivalent to converting a string directly to 436 * {@code double}. For example, the {@code float} 437 * literal {@code 0.1f} is equal to the {@code double} 438 * value {@code 0.10000000149011612}; the {@code float} 439 * literal {@code 0.1f} represents a different numerical 440 * value than the {@code double} literal 441 * {@code 0.1}. (The numerical value 0.1 cannot be exactly 442 * represented in a binary floating-point number.) 443 * 444 * <p>To avoid calling this method on an invalid string and having 445 * a {@code NumberFormatException} be thrown, the regular 446 * expression below can be used to screen the input string: 447 * 448 * <pre>{@code 449 * final String Digits = "(\\p{Digit}+)"; 450 * final String HexDigits = "(\\p{XDigit}+)"; 451 * // an exponent is 'e' or 'E' followed by an optionally 452 * // signed decimal integer. 453 * final String Exp = "[eE][+-]?"+Digits; 454 * final String fpRegex = 455 * ("[\\x00-\\x20]*"+ // Optional leading "whitespace" 456 * "[+-]?(" + // Optional sign character 457 * "NaN|" + // "NaN" string 458 * "Infinity|" + // "Infinity" string 459 * 460 * // A decimal floating-point string representing a finite positive 461 * // number without a leading sign has at most five basic pieces: 462 * // Digits . Digits ExponentPart FloatTypeSuffix 463 * // 464 * // Since this method allows integer-only strings as input 465 * // in addition to strings of floating-point literals, the 466 * // two sub-patterns below are simplifications of the grammar 467 * // productions from section 3.10.2 of 468 * // The Java Language Specification. 469 * 470 * // Digits ._opt Digits_opt ExponentPart_opt FloatTypeSuffix_opt 471 * "((("+Digits+"(\\.)?("+Digits+"?)("+Exp+")?)|"+ 472 * 473 * // . Digits ExponentPart_opt FloatTypeSuffix_opt 474 * "(\\.("+Digits+")("+Exp+")?)|"+ 475 * 476 * // Hexadecimal strings 477 * "((" + 478 * // 0[xX] HexDigits ._opt BinaryExponent FloatTypeSuffix_opt 479 * "(0[xX]" + HexDigits + "(\\.)?)|" + 480 * 481 * // 0[xX] HexDigits_opt . HexDigits BinaryExponent FloatTypeSuffix_opt 482 * "(0[xX]" + HexDigits + "?(\\.)" + HexDigits + ")" + 483 * 484 * ")[pP][+-]?" + Digits + "))" + 485 * "[fFdD]?))" + 486 * "[\\x00-\\x20]*");// Optional trailing "whitespace" 487 * 488 * if (Pattern.matches(fpRegex, myString)) 489 * Double.valueOf(myString); // Will not throw NumberFormatException 490 * else { 491 * // Perform suitable alternative action 492 * } 493 * }</pre> 494 * 495 * @param s the string to be parsed. 496 * @return a {@code Double} object holding the value 497 * represented by the {@code String} argument. 498 * @throws NumberFormatException if the string does not contain a 499 * parsable number. 500 */ 501 public static Double valueOf(String s) throws NumberFormatException { 502 return new Double(parseDouble(s)); 503 } 504 505 /** 506 * Returns a {@code Double} instance representing the specified 507 * {@code double} value. 508 * If a new {@code Double} instance is not required, this method 509 * should generally be used in preference to the constructor 510 * {@link #Double(double)}, as this method is likely to yield 511 * significantly better space and time performance by caching 512 * frequently requested values. 513 * 514 * @param d a double value. 515 * @return a {@code Double} instance representing {@code d}. 516 * @since 1.5 517 */ 518 @HotSpotIntrinsicCandidate 519 public static Double valueOf(double d) { 520 return new Double(d); 521 } 522 523 /** 524 * Returns a new {@code double} initialized to the value 525 * represented by the specified {@code String}, as performed 526 * by the {@code valueOf} method of class 527 * {@code Double}. 528 * 529 * @param s the string to be parsed. 530 * @return the {@code double} value represented by the string 531 * argument. 532 * @throws NullPointerException if the string is null 533 * @throws NumberFormatException if the string does not contain 534 * a parsable {@code double}. 535 * @see java.lang.Double#valueOf(String) 536 * @since 1.2 537 */ 538 public static double parseDouble(String s) throws NumberFormatException { 539 return FloatingDecimal.parseDouble(s); 540 } 541 542 /** 543 * Returns {@code true} if the specified number is a 544 * Not-a-Number (NaN) value, {@code false} otherwise. 545 * 546 * @param v the value to be tested. 547 * @return {@code true} if the value of the argument is NaN; 548 * {@code false} otherwise. 549 */ 550 public static boolean isNaN(double v) { 551 return (v != v); 552 } 553 554 /** 555 * Returns {@code true} if the specified number is infinitely 556 * large in magnitude, {@code false} otherwise. 557 * 558 * @param v the value to be tested. 559 * @return {@code true} if the value of the argument is positive 560 * infinity or negative infinity; {@code false} otherwise. 561 */ 562 public static boolean isInfinite(double v) { 563 return (v == POSITIVE_INFINITY) || (v == NEGATIVE_INFINITY); 564 } 565 566 /** 567 * Returns {@code true} if the argument is a finite floating-point 568 * value; returns {@code false} otherwise (for NaN and infinity 569 * arguments). 570 * 571 * @param d the {@code double} value to be tested 572 * @return {@code true} if the argument is a finite 573 * floating-point value, {@code false} otherwise. 574 * @since 1.8 575 */ 576 public static boolean isFinite(double d) { 577 return Math.abs(d) <= DoubleConsts.MAX_VALUE; 578 } 579 580 /** 581 * The value of the Double. 582 * 583 * @serial 584 */ 585 private final double value; 586 587 /** 588 * Constructs a newly allocated {@code Double} object that 589 * represents the primitive {@code double} argument. 590 * 591 * @param value the value to be represented by the {@code Double}. 592 */ 593 public Double(double value) { 594 this.value = value; 595 } 596 597 /** 598 * Constructs a newly allocated {@code Double} object that 599 * represents the floating-point value of type {@code double} 600 * represented by the string. The string is converted to a 601 * {@code double} value as if by the {@code valueOf} method. 602 * 603 * @param s a string to be converted to a {@code Double}. 604 * @throws NumberFormatException if the string does not contain a 605 * parsable number. 606 * @see java.lang.Double#valueOf(java.lang.String) 607 */ 608 public Double(String s) throws NumberFormatException { 609 value = parseDouble(s); 610 } 611 612 /** 613 * Returns {@code true} if this {@code Double} value is 614 * a Not-a-Number (NaN), {@code false} otherwise. 615 * 616 * @return {@code true} if the value represented by this object is 617 * NaN; {@code false} otherwise. 618 */ 619 public boolean isNaN() { 620 return isNaN(value); 621 } 622 623 /** 624 * Returns {@code true} if this {@code Double} value is 625 * infinitely large in magnitude, {@code false} otherwise. 626 * 627 * @return {@code true} if the value represented by this object is 628 * positive infinity or negative infinity; 629 * {@code false} otherwise. 630 */ 631 public boolean isInfinite() { 632 return isInfinite(value); 633 } 634 635 /** 636 * Returns a string representation of this {@code Double} object. 637 * The primitive {@code double} value represented by this 638 * object is converted to a string exactly as if by the method 639 * {@code toString} of one argument. 640 * 641 * @return a {@code String} representation of this object. 642 * @see java.lang.Double#toString(double) 643 */ 644 public String toString() { 645 return toString(value); 646 } 647 648 /** 649 * Returns the value of this {@code Double} as a {@code byte} 650 * after a narrowing primitive conversion. 651 * 652 * @return the {@code double} value represented by this object 653 * converted to type {@code byte} 654 * @jls 5.1.3 Narrowing Primitive Conversions 655 * @since 1.1 656 */ 657 public byte byteValue() { 658 return (byte)value; 659 } 660 661 /** 662 * Returns the value of this {@code Double} as a {@code short} 663 * after a narrowing primitive conversion. 664 * 665 * @return the {@code double} value represented by this object 666 * converted to type {@code short} 667 * @jls 5.1.3 Narrowing Primitive Conversions 668 * @since 1.1 669 */ 670 public short shortValue() { 671 return (short)value; 672 } 673 674 /** 675 * Returns the value of this {@code Double} as an {@code int} 676 * after a narrowing primitive conversion. 677 * @jls 5.1.3 Narrowing Primitive Conversions 678 * 679 * @return the {@code double} value represented by this object 680 * converted to type {@code int} 681 */ 682 public int intValue() { 683 return (int)value; 684 } 685 686 /** 687 * Returns the value of this {@code Double} as a {@code long} 688 * after a narrowing primitive conversion. 689 * 690 * @return the {@code double} value represented by this object 691 * converted to type {@code long} 692 * @jls 5.1.3 Narrowing Primitive Conversions 693 */ 694 public long longValue() { 695 return (long)value; 696 } 697 698 /** 699 * Returns the value of this {@code Double} as a {@code float} 700 * after a narrowing primitive conversion. 701 * 702 * @return the {@code double} value represented by this object 703 * converted to type {@code float} 704 * @jls 5.1.3 Narrowing Primitive Conversions 705 * @since 1.0 706 */ 707 public float floatValue() { 708 return (float)value; 709 } 710 711 /** 712 * Returns the {@code double} value of this {@code Double} object. 713 * 714 * @return the {@code double} value represented by this object 715 */ 716 @HotSpotIntrinsicCandidate 717 public double doubleValue() { 718 return value; 719 } 720 721 /** 722 * Returns a hash code for this {@code Double} object. The 723 * result is the exclusive OR of the two halves of the 724 * {@code long} integer bit representation, exactly as 725 * produced by the method {@link #doubleToLongBits(double)}, of 726 * the primitive {@code double} value represented by this 727 * {@code Double} object. That is, the hash code is the value 728 * of the expression: 729 * 730 * <blockquote> 731 * {@code (int)(v^(v>>>32))} 732 * </blockquote> 733 * 734 * where {@code v} is defined by: 735 * 736 * <blockquote> 737 * {@code long v = Double.doubleToLongBits(this.doubleValue());} 738 * </blockquote> 739 * 740 * @return a {@code hash code} value for this object. 741 */ 742 @Override 743 public int hashCode() { 744 return Double.hashCode(value); 745 } 746 747 /** 748 * Returns a hash code for a {@code double} value; compatible with 749 * {@code Double.hashCode()}. 750 * 751 * @param value the value to hash 752 * @return a hash code value for a {@code double} value. 753 * @since 1.8 754 */ 755 public static int hashCode(double value) { 756 long bits = doubleToLongBits(value); 757 return (int)(bits ^ (bits >>> 32)); 758 } 759 760 /** 761 * Compares this object against the specified object. The result 762 * is {@code true} if and only if the argument is not 763 * {@code null} and is a {@code Double} object that 764 * represents a {@code double} that has the same value as the 765 * {@code double} represented by this object. For this 766 * purpose, two {@code double} values are considered to be 767 * the same if and only if the method {@link 768 * #doubleToLongBits(double)} returns the identical 769 * {@code long} value when applied to each. 770 * 771 * <p>Note that in most cases, for two instances of class 772 * {@code Double}, {@code d1} and {@code d2}, the 773 * value of {@code d1.equals(d2)} is {@code true} if and 774 * only if 775 * 776 * <blockquote> 777 * {@code d1.doubleValue() == d2.doubleValue()} 778 * </blockquote> 779 * 780 * <p>also has the value {@code true}. However, there are two 781 * exceptions: 782 * <ul> 783 * <li>If {@code d1} and {@code d2} both represent 784 * {@code Double.NaN}, then the {@code equals} method 785 * returns {@code true}, even though 786 * {@code Double.NaN==Double.NaN} has the value 787 * {@code false}. 788 * <li>If {@code d1} represents {@code +0.0} while 789 * {@code d2} represents {@code -0.0}, or vice versa, 790 * the {@code equal} test has the value {@code false}, 791 * even though {@code +0.0==-0.0} has the value {@code true}. 792 * </ul> 793 * This definition allows hash tables to operate properly. 794 * @param obj the object to compare with. 795 * @return {@code true} if the objects are the same; 796 * {@code false} otherwise. 797 * @see java.lang.Double#doubleToLongBits(double) 798 */ 799 public boolean equals(Object obj) { 800 return (obj instanceof Double) 801 && (doubleToLongBits(((Double)obj).value) == 802 doubleToLongBits(value)); 803 } 804 805 /** 806 * Returns a representation of the specified floating-point value 807 * according to the IEEE 754 floating-point "double 808 * format" bit layout. 809 * 810 * <p>Bit 63 (the bit that is selected by the mask 811 * {@code 0x8000000000000000L}) represents the sign of the 812 * floating-point number. Bits 813 * 62-52 (the bits that are selected by the mask 814 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 815 * (the bits that are selected by the mask 816 * {@code 0x000fffffffffffffL}) represent the significand 817 * (sometimes called the mantissa) of the floating-point number. 818 * 819 * <p>If the argument is positive infinity, the result is 820 * {@code 0x7ff0000000000000L}. 821 * 822 * <p>If the argument is negative infinity, the result is 823 * {@code 0xfff0000000000000L}. 824 * 825 * <p>If the argument is NaN, the result is 826 * {@code 0x7ff8000000000000L}. 827 * 828 * <p>In all cases, the result is a {@code long} integer that, when 829 * given to the {@link #longBitsToDouble(long)} method, will produce a 830 * floating-point value the same as the argument to 831 * {@code doubleToLongBits} (except all NaN values are 832 * collapsed to a single "canonical" NaN value). 833 * 834 * @param value a {@code double} precision floating-point number. 835 * @return the bits that represent the floating-point number. 836 */ 837 @HotSpotIntrinsicCandidate 838 public static long doubleToLongBits(double value) { 839 if (!isNaN(value)) { 840 return doubleToRawLongBits(value); 841 } 842 return 0x7ff8000000000000L; 843 } 844 845 /** 846 * Returns a representation of the specified floating-point value 847 * according to the IEEE 754 floating-point "double 848 * format" bit layout, preserving Not-a-Number (NaN) values. 849 * 850 * <p>Bit 63 (the bit that is selected by the mask 851 * {@code 0x8000000000000000L}) represents the sign of the 852 * floating-point number. Bits 853 * 62-52 (the bits that are selected by the mask 854 * {@code 0x7ff0000000000000L}) represent the exponent. Bits 51-0 855 * (the bits that are selected by the mask 856 * {@code 0x000fffffffffffffL}) represent the significand 857 * (sometimes called the mantissa) of the floating-point number. 858 * 859 * <p>If the argument is positive infinity, the result is 860 * {@code 0x7ff0000000000000L}. 861 * 862 * <p>If the argument is negative infinity, the result is 863 * {@code 0xfff0000000000000L}. 864 * 865 * <p>If the argument is NaN, the result is the {@code long} 866 * integer representing the actual NaN value. Unlike the 867 * {@code doubleToLongBits} method, 868 * {@code doubleToRawLongBits} does not collapse all the bit 869 * patterns encoding a NaN to a single "canonical" NaN 870 * value. 871 * 872 * <p>In all cases, the result is a {@code long} integer that, 873 * when given to the {@link #longBitsToDouble(long)} method, will 874 * produce a floating-point value the same as the argument to 875 * {@code doubleToRawLongBits}. 876 * 877 * @param value a {@code double} precision floating-point number. 878 * @return the bits that represent the floating-point number. 879 * @since 1.3 880 */ 881 @HotSpotIntrinsicCandidate 882 public static native long doubleToRawLongBits(double value); 883 884 /** 885 * Returns the {@code double} value corresponding to a given 886 * bit representation. 887 * The argument is considered to be a representation of a 888 * floating-point value according to the IEEE 754 floating-point 889 * "double format" bit layout. 890 * 891 * <p>If the argument is {@code 0x7ff0000000000000L}, the result 892 * is positive infinity. 893 * 894 * <p>If the argument is {@code 0xfff0000000000000L}, the result 895 * is negative infinity. 896 * 897 * <p>If the argument is any value in the range 898 * {@code 0x7ff0000000000001L} through 899 * {@code 0x7fffffffffffffffL} or in the range 900 * {@code 0xfff0000000000001L} through 901 * {@code 0xffffffffffffffffL}, the result is a NaN. No IEEE 902 * 754 floating-point operation provided by Java can distinguish 903 * between two NaN values of the same type with different bit 904 * patterns. Distinct values of NaN are only distinguishable by 905 * use of the {@code Double.doubleToRawLongBits} method. 906 * 907 * <p>In all other cases, let <i>s</i>, <i>e</i>, and <i>m</i> be three 908 * values that can be computed from the argument: 909 * 910 * <blockquote><pre>{@code 911 * int s = ((bits >> 63) == 0) ? 1 : -1; 912 * int e = (int)((bits >> 52) & 0x7ffL); 913 * long m = (e == 0) ? 914 * (bits & 0xfffffffffffffL) << 1 : 915 * (bits & 0xfffffffffffffL) | 0x10000000000000L; 916 * }</pre></blockquote> 917 * 918 * Then the floating-point result equals the value of the mathematical 919 * expression <i>s</i>·<i>m</i>·2<sup><i>e</i>-1075</sup>. 920 * 921 * <p>Note that this method may not be able to return a 922 * {@code double} NaN with exactly same bit pattern as the 923 * {@code long} argument. IEEE 754 distinguishes between two 924 * kinds of NaNs, quiet NaNs and <i>signaling NaNs</i>. The 925 * differences between the two kinds of NaN are generally not 926 * visible in Java. Arithmetic operations on signaling NaNs turn 927 * them into quiet NaNs with a different, but often similar, bit 928 * pattern. However, on some processors merely copying a 929 * signaling NaN also performs that conversion. In particular, 930 * copying a signaling NaN to return it to the calling method 931 * may perform this conversion. So {@code longBitsToDouble} 932 * may not be able to return a {@code double} with a 933 * signaling NaN bit pattern. Consequently, for some 934 * {@code long} values, 935 * {@code doubleToRawLongBits(longBitsToDouble(start))} may 936 * <i>not</i> equal {@code start}. Moreover, which 937 * particular bit patterns represent signaling NaNs is platform 938 * dependent; although all NaN bit patterns, quiet or signaling, 939 * must be in the NaN range identified above. 940 * 941 * @param bits any {@code long} integer. 942 * @return the {@code double} floating-point value with the same 943 * bit pattern. 944 */ 945 @HotSpotIntrinsicCandidate 946 public static native double longBitsToDouble(long bits); 947 948 /** 949 * Compares two {@code Double} objects numerically. There 950 * are two ways in which comparisons performed by this method 951 * differ from those performed by the Java language numerical 952 * comparison operators ({@code <, <=, ==, >=, >}) 953 * when applied to primitive {@code double} values: 954 * <ul><li> 955 * {@code Double.NaN} is considered by this method 956 * to be equal to itself and greater than all other 957 * {@code double} values (including 958 * {@code Double.POSITIVE_INFINITY}). 959 * <li> 960 * {@code 0.0d} is considered by this method to be greater 961 * than {@code -0.0d}. 962 * </ul> 963 * This ensures that the <i>natural ordering</i> of 964 * {@code Double} objects imposed by this method is <i>consistent 965 * with equals</i>. 966 * 967 * @param anotherDouble the {@code Double} to be compared. 968 * @return the value {@code 0} if {@code anotherDouble} is 969 * numerically equal to this {@code Double}; a value 970 * less than {@code 0} if this {@code Double} 971 * is numerically less than {@code anotherDouble}; 972 * and a value greater than {@code 0} if this 973 * {@code Double} is numerically greater than 974 * {@code anotherDouble}. 975 * 976 * @since 1.2 977 */ 978 public int compareTo(Double anotherDouble) { 979 return Double.compare(value, anotherDouble.value); 980 } 981 982 /** 983 * Compares the two specified {@code double} values. The sign 984 * of the integer value returned is the same as that of the 985 * integer that would be returned by the call: 986 * <pre> 987 * new Double(d1).compareTo(new Double(d2)) 988 * </pre> 989 * 990 * @param d1 the first {@code double} to compare 991 * @param d2 the second {@code double} to compare 992 * @return the value {@code 0} if {@code d1} is 993 * numerically equal to {@code d2}; a value less than 994 * {@code 0} if {@code d1} is numerically less than 995 * {@code d2}; and a value greater than {@code 0} 996 * if {@code d1} is numerically greater than 997 * {@code d2}. 998 * @since 1.4 999 */ 1000 public static int compare(double d1, double d2) { 1001 if (d1 < d2) 1002 return -1; // Neither val is NaN, thisVal is smaller 1003 if (d1 > d2) 1004 return 1; // Neither val is NaN, thisVal is larger 1005 1006 // Cannot use doubleToRawLongBits because of possibility of NaNs. 1007 long thisBits = Double.doubleToLongBits(d1); 1008 long anotherBits = Double.doubleToLongBits(d2); 1009 1010 return (thisBits == anotherBits ? 0 : // Values are equal 1011 (thisBits < anotherBits ? -1 : // (-0.0, 0.0) or (!NaN, NaN) 1012 1)); // (0.0, -0.0) or (NaN, !NaN) 1013 } 1014 1015 /** 1016 * Adds two {@code double} values together as per the + operator. 1017 * 1018 * @param a the first operand 1019 * @param b the second operand 1020 * @return the sum of {@code a} and {@code b} 1021 * @jls 4.2.4 Floating-Point Operations 1022 * @see java.util.function.BinaryOperator 1023 * @since 1.8 1024 */ 1025 public static double sum(double a, double b) { 1026 return a + b; 1027 } 1028 1029 /** 1030 * Returns the greater of two {@code double} values 1031 * as if by calling {@link Math#max(double, double) Math.max}. 1032 * 1033 * @param a the first operand 1034 * @param b the second operand 1035 * @return the greater of {@code a} and {@code b} 1036 * @see java.util.function.BinaryOperator 1037 * @since 1.8 1038 */ 1039 public static double max(double a, double b) { 1040 return Math.max(a, b); 1041 } 1042 1043 /** 1044 * Returns the smaller of two {@code double} values 1045 * as if by calling {@link Math#min(double, double) Math.min}. 1046 * 1047 * @param a the first operand 1048 * @param b the second operand 1049 * @return the smaller of {@code a} and {@code b}. 1050 * @see java.util.function.BinaryOperator 1051 * @since 1.8 1052 */ 1053 public static double min(double a, double b) { 1054 return Math.min(a, b); 1055 } 1056 1057 /** use serialVersionUID from JDK 1.0.2 for interoperability */ 1058 private static final long serialVersionUID = -9172774392245257468L; 1059 }