src/share/classes/java/time/Duration.java

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  44  *    and/or other materials provided with the distribution.
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  46  *  * Neither the name of JSR-310 nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  51  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  52  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  53  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  54  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  55  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  56  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  57  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  58  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  59  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  60  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  61  */
  62 package java.time;
  63 

  64 import static java.time.LocalTime.SECONDS_PER_DAY;
  65 import static java.time.temporal.ChronoField.INSTANT_SECONDS;

  66 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
  67 import static java.time.temporal.ChronoUnit.DAYS;


  68 
  69 import java.io.DataInput;
  70 import java.io.DataOutput;
  71 import java.io.IOException;
  72 import java.io.InvalidObjectException;
  73 import java.io.ObjectStreamException;
  74 import java.io.Serializable;
  75 import java.math.BigDecimal;
  76 import java.math.BigInteger;
  77 import java.math.RoundingMode;
  78 import java.time.format.DateTimeParseException;
  79 import java.time.temporal.ChronoField;
  80 import java.time.temporal.ChronoUnit;
  81 import java.time.temporal.Temporal;
  82 import java.time.temporal.TemporalAccessor;
  83 import java.time.temporal.TemporalAdder;
  84 import java.time.temporal.TemporalSubtractor;
  85 import java.time.temporal.TemporalUnit;



  86 import java.util.Objects;


  87 
  88 /**
  89  * A duration between two instants on the time-line.
  90  * <p>
  91  * This class models a duration of time and is not tied to any instant.
  92  * The model is of a directed duration, meaning that the duration may be negative.



  93  * <p>
  94  * A physical duration could be of infinite length.
  95  * For practicality, the duration is stored with constraints similar to {@link Instant}.
  96  * The duration uses nanosecond resolution with a maximum value of the seconds that can
  97  * be held in a {@code long}. This is greater than the current estimated age of the universe.
  98  * <p>
  99  * The range of a duration requires the storage of a number larger than a {@code long}.
 100  * To achieve this, the class stores a {@code long} representing seconds and an {@code int}
 101  * representing nanosecond-of-second, which will always be between 0 and 999,999,999.

 102  * <p>
 103  * The duration is measured in "seconds", but these are not necessarily identical to
 104  * the scientific "SI second" definition based on atomic clocks.
 105  * This difference only impacts durations measured near a leap-second and should not affect
 106  * most applications.
 107  * See {@link Instant} for a discussion as to the meaning of the second and time-scales.
 108  *
 109  * <h3>Specification for implementors</h3>
 110  * This class is immutable and thread-safe.
 111  *
 112  * @since 1.8
 113  */
 114 public final class Duration
 115         implements TemporalAdder, TemporalSubtractor, Comparable<Duration>, Serializable {
 116 
 117     /**
 118      * Constant for a duration of zero.
 119      */
 120     public static final Duration ZERO = new Duration(0, 0);
 121     /**
 122      * Serialization version.
 123      */
 124     private static final long serialVersionUID = 3078945930695997490L;
 125     /**
 126      * Constant for nanos per second.
 127      */
 128     private static final int NANOS_PER_SECOND = 1000_000_000;
 129     /**
 130      * Constant for nanos per second.
 131      */
 132     private static final BigInteger BI_NANOS_PER_SECOND = BigInteger.valueOf(NANOS_PER_SECOND);



 133 
 134     /**
 135      * The number of seconds in the duration.
 136      */
 137     private final long seconds;
 138     /**
 139      * The number of nanoseconds in the duration, expressed as a fraction of the
 140      * number of seconds. This is always positive, and never exceeds 999,999,999.
 141      */
 142     private final int nanos;
 143 
 144     //-----------------------------------------------------------------------
 145     /**
 146      * Obtains an instance of {@code Duration} from a number of seconds.














































 147      * <p>
 148      * The nanosecond in second field is set to zero.
 149      *
 150      * @param seconds  the number of seconds, positive or negative
 151      * @return a {@code Duration}, not null
 152      */
 153     public static Duration ofSeconds(long seconds) {
 154         return create(seconds, 0);
 155     }
 156 
 157     /**
 158      * Obtains an instance of {@code Duration} from a number of seconds
 159      * and an adjustment in nanoseconds.
 160      * <p>
 161      * This method allows an arbitrary number of nanoseconds to be passed in.
 162      * The factory will alter the values of the second and nanosecond in order
 163      * to ensure that the stored nanosecond is in the range 0 to 999,999,999.
 164      * For example, the following will result in the exactly the same duration:
 165      * <pre>
 166      *  Duration.ofSeconds(3, 1);
 167      *  Duration.ofSeconds(4, -999_999_999);
 168      *  Duration.ofSeconds(2, 1000_000_001);
 169      * </pre>
 170      *
 171      * @param seconds  the number of seconds, positive or negative
 172      * @param nanoAdjustment  the nanosecond adjustment to the number of seconds, positive or negative
 173      * @return a {@code Duration}, not null
 174      * @throws ArithmeticException if the adjustment causes the seconds to exceed the capacity of {@code Duration}
 175      */
 176     public static Duration ofSeconds(long seconds, long nanoAdjustment) {
 177         long secs = Math.addExact(seconds, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND));
 178         int nos = (int)Math.floorMod(nanoAdjustment, NANOS_PER_SECOND);
 179         return create(secs, nos);
 180     }
 181 
 182     //-----------------------------------------------------------------------
 183     /**
 184      * Obtains an instance of {@code Duration} from a number of milliseconds.
 185      * <p>
 186      * The seconds and nanoseconds are extracted from the specified milliseconds.
 187      *
 188      * @param millis  the number of milliseconds, positive or negative
 189      * @return a {@code Duration}, not null
 190      */
 191     public static Duration ofMillis(long millis) {
 192         long secs = millis / 1000;
 193         int mos = (int) (millis % 1000);
 194         if (mos < 0) {
 195             mos += 1000;
 196             secs--;
 197         }
 198         return create(secs, mos * 1000_000);
 199     }
 200 
 201     //-----------------------------------------------------------------------
 202     /**
 203      * Obtains an instance of {@code Duration} from a number of nanoseconds.
 204      * <p>
 205      * The seconds and nanoseconds are extracted from the specified nanoseconds.
 206      *
 207      * @param nanos  the number of nanoseconds, positive or negative
 208      * @return a {@code Duration}, not null
 209      */
 210     public static Duration ofNanos(long nanos) {
 211         long secs = nanos / NANOS_PER_SECOND;
 212         int nos = (int) (nanos % NANOS_PER_SECOND);
 213         if (nos < 0) {
 214             nos += NANOS_PER_SECOND;
 215             secs--;
 216         }
 217         return create(secs, nos);
 218     }
 219 
 220     //-----------------------------------------------------------------------
 221     /**
 222      * Obtains an instance of {@code Duration} from a number of standard length minutes.
 223      * <p>
 224      * The seconds are calculated based on the standard definition of a minute,
 225      * where each minute is 60 seconds.
 226      * The nanosecond in second field is set to zero.
 227      *
 228      * @param minutes  the number of minutes, positive or negative
 229      * @return a {@code Duration}, not null
 230      * @throws ArithmeticException if the input minutes exceeds the capacity of {@code Duration}
 231      */
 232     public static Duration ofMinutes(long minutes) {
 233         return create(Math.multiplyExact(minutes, 60), 0);
 234     }
 235 
 236     /**
 237      * Obtains an instance of {@code Duration} from a number of standard length hours.
 238      * <p>
 239      * The seconds are calculated based on the standard definition of an hour,
 240      * where each hour is 3600 seconds.
 241      * The nanosecond in second field is set to zero.
 242      *
 243      * @param hours  the number of hours, positive or negative
 244      * @return a {@code Duration}, not null
 245      * @throws ArithmeticException if the input hours exceeds the capacity of {@code Duration}
 246      */
 247     public static Duration ofHours(long hours) {
 248         return create(Math.multiplyExact(hours, 3600), 0);
 249     }
 250 
 251     /**
 252      * Obtains an instance of {@code Duration} from a number of standard 24 hour days.
 253      * <p>
 254      * The seconds are calculated based on the standard definition of a day,
 255      * where each day is 86400 seconds which implies a 24 hour day.
 256      * The nanosecond in second field is set to zero.
 257      *
 258      * @param days  the number of days, positive or negative
 259      * @return a {@code Duration}, not null
 260      * @throws ArithmeticException if the input days exceeds the capacity of {@code Duration}
 261      */
 262     public static Duration ofDays(long days) {
 263         return create(Math.multiplyExact(days, 86400), 0);
 264     }
 265 
 266     //-----------------------------------------------------------------------
 267     /**
 268      * Obtains an instance of {@code Duration} from a duration in the specified unit.
 269      * <p>
 270      * The parameters represent the two parts of a phrase like '6 Hours'. For example:
 271      * <pre>
 272      *  Duration.of(3, SECONDS);
 273      *  Duration.of(465, HOURS);
 274      * </pre>
 275      * Only a subset of units are accepted by this method.
 276      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 277      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 278      *
 279      * @param amount  the amount of the duration, measured in terms of the unit, positive or negative
 280      * @param unit  the unit that the duration is measured in, must have an exact duration, not null
 281      * @return a {@code Duration}, not null
 282      * @throws DateTimeException if the period unit has an estimated duration
 283      * @throws ArithmeticException if a numeric overflow occurs
 284      */
 285     public static Duration of(long amount, TemporalUnit unit) {
 286         return ZERO.plus(amount, unit);
 287     }
 288 
 289     //-----------------------------------------------------------------------
 290     /**
 291      * Obtains an instance of {@code Duration} representing the duration between two instants.
 292      * <p>
 293      * A {@code Duration} represents a directed distance between two points on the time-line.
 294      * As such, this method will return a negative duration if the end is before the start.
 295      * To guarantee to obtain a positive duration call {@link #abs()} on the result of this factory.





 296      *
 297      * @param startInclusive  the start instant, inclusive, not null
 298      * @param endExclusive  the end instant, exclusive, not null
 299      * @return a {@code Duration}, not null
 300      * @throws ArithmeticException if the calculation exceeds the capacity of {@code Duration}
 301      */
 302     public static Duration between(TemporalAccessor startInclusive, TemporalAccessor endExclusive) {
 303         long secs = Math.subtractExact(endExclusive.getLong(INSTANT_SECONDS), startInclusive.getLong(INSTANT_SECONDS));
 304         long nanos = endExclusive.getLong(NANO_OF_SECOND) - startInclusive.getLong(NANO_OF_SECOND);
 305         secs = Math.addExact(secs, Math.floorDiv(nanos, NANOS_PER_SECOND));
 306         nanos = Math.floorMod(nanos, NANOS_PER_SECOND);
 307         return create(secs, (int) nanos);  // safe from overflow



 308     }
 309 
 310     //-----------------------------------------------------------------------
 311     /**
 312      * Obtains an instance of {@code Duration} by parsing a text string.
 313      * <p>
 314      * This will parse the string produced by {@link #toString()} which is
 315      * the ISO-8601 format {@code PTnS} where {@code n} is
 316      * the number of seconds with optional decimal part.
 317      * The number must consist of ASCII numerals.
 318      * There must only be a negative sign at the start of the number and it can
 319      * only be present if the value is less than zero.
 320      * There must be at least one digit before any decimal point.
 321      * There must be between 1 and 9 inclusive digits after any decimal point.
 322      * The letters (P, T and S) will be accepted in upper or lower case.










 323      * The decimal point may be either a dot or a comma.
















 324      *
 325      * @param text  the text to parse, not null
 326      * @return a {@code Duration}, not null
 327      * @throws DateTimeParseException if the text cannot be parsed to a {@code Duration}
 328      */
 329     public static Duration parse(final CharSequence text) {
 330         Objects.requireNonNull(text, "text");
 331         int len = text.length();
 332         if (len < 4 ||
 333                 (text.charAt(0) != 'P' && text.charAt(0) != 'p') ||
 334                 (text.charAt(1) != 'T' && text.charAt(1) != 't') ||
 335                 (text.charAt(len - 1) != 'S' && text.charAt(len - 1) != 's') ||
 336                 (len == 5 && text.charAt(2) == '-' && text.charAt(3) == '0')) {
 337             throw new DateTimeParseException("Duration could not be parsed: " + text, text, 0);
 338         }
 339         String numberText = text.subSequence(2, len - 1).toString().replace(',', '.');
 340         if (numberText.charAt(0) == '+') {
 341             throw new DateTimeParseException("Duration could not be parsed: " + text, text, 2);

































 342         }
 343         int dot = numberText.indexOf('.');
 344         try {
 345             if (dot == -1) {
 346                 // no decimal places
 347                 if (numberText.startsWith("-0")) {
 348                     throw new DateTimeParseException("Duration could not be parsed: " + text, text, 2);
 349                 }
 350                 return create(Long.parseLong(numberText), 0);
 351             }
 352             // decimal places
 353             boolean negative = false;
 354             if (numberText.charAt(0) == '-') {
 355                 negative = true;
 356             }
 357             long secs = Long.parseLong(numberText.substring(0, dot));
 358             numberText = numberText.substring(dot + 1);
 359             len = numberText.length();
 360             if (len == 0 || len > 9 || numberText.charAt(0) == '-' || numberText.charAt(0) == '+') {
 361                 throw new DateTimeParseException("Duration could not be parsed: " + text, text, 2);
 362             }
 363             int nanos = Integer.parseInt(numberText);
 364             switch (len) {
 365                 case 1:
 366                     nanos *= 100000000;
 367                     break;
 368                 case 2:
 369                     nanos *= 10000000;
 370                     break;
 371                 case 3:
 372                     nanos *= 1000000;
 373                     break;
 374                 case 4:
 375                     nanos *= 100000;
 376                     break;
 377                 case 5:
 378                     nanos *= 10000;
 379                     break;
 380                 case 6:
 381                     nanos *= 1000;
 382                     break;
 383                 case 7:
 384                     nanos *= 100;
 385                     break;
 386                 case 8:
 387                     nanos *= 10;
 388                     break;
 389             }
 390             return negative ? ofSeconds(secs, -nanos) : create(secs, nanos);
 391 
 392         } catch (ArithmeticException | NumberFormatException ex) {
 393             throw new DateTimeParseException("Duration could not be parsed: " + text, text, 2, ex);


 394         }

 395     }
 396 
 397     //-----------------------------------------------------------------------
 398     /**
 399      * Obtains an instance of {@code Duration} using seconds and nanoseconds.
 400      *
 401      * @param seconds  the length of the duration in seconds, positive or negative
 402      * @param nanoAdjustment  the nanosecond adjustment within the second, from 0 to 999,999,999
 403      */
 404     private static Duration create(long seconds, int nanoAdjustment) {
 405         if ((seconds | nanoAdjustment) == 0) {
 406             return ZERO;
 407         }
 408         return new Duration(seconds, nanoAdjustment);
 409     }
 410 
 411     /**
 412      * Constructs an instance of {@code Duration} using seconds and nanoseconds.
 413      *
 414      * @param seconds  the length of the duration in seconds, positive or negative
 415      * @param nanos  the nanoseconds within the second, from 0 to 999,999,999
 416      */
 417     private Duration(long seconds, int nanos) {
 418         super();
 419         this.seconds = seconds;
 420         this.nanos = nanos;
 421     }
 422 
 423     //-----------------------------------------------------------------------
 424     /**
 425      * Checks if this duration is zero length.
 426      * <p>
 427      * A {@code Duration} represents a directed distance between two points on
 428      * the time-line and can therefore be positive, zero or negative.
 429      * This method checks whether the length is zero.

























 430      *
 431      * @return true if this duration has a total length equal to zero
 432      */
 433     public boolean isZero() {
 434         return (seconds | nanos) == 0;











 435     }
 436 

 437     /**
 438      * Checks if this duration is positive, excluding zero.
 439      * <p>
 440      * A {@code Duration} represents a directed distance between two points on
 441      * the time-line and can therefore be positive, zero or negative.
 442      * This method checks whether the length is greater than zero.
 443      *
 444      * @return true if this duration has a total length greater than zero
 445      */
 446     public boolean isPositive() {
 447         return seconds >= 0 && ((seconds | nanos) != 0);
 448     }
 449 
 450     /**
 451      * Checks if this duration is negative, excluding zero.
 452      * <p>
 453      * A {@code Duration} represents a directed distance between two points on
 454      * the time-line and can therefore be positive, zero or negative.
 455      * This method checks whether the length is less than zero.
 456      *
 457      * @return true if this duration has a total length less than zero
 458      */
 459     public boolean isNegative() {
 460         return seconds < 0;
 461     }
 462 
 463     //-----------------------------------------------------------------------
 464     /**
 465      * Gets the number of seconds in this duration.
 466      * <p>
 467      * The length of the duration is stored using two fields - seconds and nanoseconds.


 482     /**
 483      * Gets the number of nanoseconds within the second in this duration.
 484      * <p>
 485      * The length of the duration is stored using two fields - seconds and nanoseconds.
 486      * The nanoseconds part is a value from 0 to 999,999,999 that is an adjustment to
 487      * the length in seconds.
 488      * The total duration is defined by calling this method and {@link #getSeconds()}.
 489      * <p>
 490      * A {@code Duration} represents a directed distance between two points on the time-line.
 491      * A negative duration is expressed by the negative sign of the seconds part.
 492      * A duration of -1 nanosecond is stored as -1 seconds plus 999,999,999 nanoseconds.
 493      *
 494      * @return the nanoseconds within the second part of the length of the duration, from 0 to 999,999,999
 495      */
 496     public int getNano() {
 497         return nanos;
 498     }
 499 
 500     //-----------------------------------------------------------------------
 501     /**

































 502      * Returns a copy of this duration with the specified duration added.
 503      * <p>
 504      * This instance is immutable and unaffected by this method call.
 505      *
 506      * @param duration  the duration to add, positive or negative, not null
 507      * @return a {@code Duration} based on this duration with the specified duration added, not null
 508      * @throws ArithmeticException if numeric overflow occurs
 509      */
 510     public Duration plus(Duration duration) {
 511         return plus(duration.getSeconds(), duration.getNano());
 512      }
 513 
 514     /**
 515      * Returns a copy of this duration with the specified duration added.
 516      * <p>
 517      * The duration amount is measured in terms of the specified unit.
 518      * Only a subset of units are accepted by this method.
 519      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 520      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 521      * <p>


 535             throw new DateTimeException("Unit must not have an estimated duration");
 536         }
 537         if (amountToAdd == 0) {
 538             return this;
 539         }
 540         if (unit instanceof ChronoUnit) {
 541             switch ((ChronoUnit) unit) {
 542                 case NANOS: return plusNanos(amountToAdd);
 543                 case MICROS: return plusSeconds((amountToAdd / (1000_000L * 1000)) * 1000).plusNanos((amountToAdd % (1000_000L * 1000)) * 1000);
 544                 case MILLIS: return plusMillis(amountToAdd);
 545                 case SECONDS: return plusSeconds(amountToAdd);
 546             }
 547             return plusSeconds(Math.multiplyExact(unit.getDuration().seconds, amountToAdd));
 548         }
 549         Duration duration = unit.getDuration().multipliedBy(amountToAdd);
 550         return plusSeconds(duration.getSeconds()).plusNanos(duration.getNano());
 551     }
 552 
 553     //-----------------------------------------------------------------------
 554     /**










































 555      * Returns a copy of this duration with the specified duration in seconds added.
 556      * <p>
 557      * This instance is immutable and unaffected by this method call.
 558      *
 559      * @param secondsToAdd  the seconds to add, positive or negative
 560      * @return a {@code Duration} based on this duration with the specified seconds added, not null
 561      * @throws ArithmeticException if numeric overflow occurs
 562      */
 563     public Duration plusSeconds(long secondsToAdd) {
 564         return plus(secondsToAdd, 0);
 565     }
 566 
 567     /**
 568      * Returns a copy of this duration with the specified duration in milliseconds added.
 569      * <p>
 570      * This instance is immutable and unaffected by this method call.
 571      *
 572      * @param millisToAdd  the milliseconds to add, positive or negative
 573      * @return a {@code Duration} based on this duration with the specified milliseconds added, not null
 574      * @throws ArithmeticException if numeric overflow occurs


 634      * Returns a copy of this duration with the specified duration subtracted.
 635      * <p>
 636      * The duration amount is measured in terms of the specified unit.
 637      * Only a subset of units are accepted by this method.
 638      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 639      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 640      * <p>
 641      * This instance is immutable and unaffected by this method call.
 642      *
 643      * @param amountToSubtract  the amount of the period, measured in terms of the unit, positive or negative
 644      * @param unit  the unit that the period is measured in, must have an exact duration, not null
 645      * @return a {@code Duration} based on this duration with the specified duration subtracted, not null
 646      * @throws ArithmeticException if numeric overflow occurs
 647      */
 648     public Duration minus(long amountToSubtract, TemporalUnit unit) {
 649         return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
 650     }
 651 
 652     //-----------------------------------------------------------------------
 653     /**














































 654      * Returns a copy of this duration with the specified duration in seconds subtracted.
 655      * <p>
 656      * This instance is immutable and unaffected by this method call.
 657      *
 658      * @param secondsToSubtract  the seconds to subtract, positive or negative
 659      * @return a {@code Duration} based on this duration with the specified seconds subtracted, not null
 660      * @throws ArithmeticException if numeric overflow occurs
 661      */
 662     public Duration minusSeconds(long secondsToSubtract) {
 663         return (secondsToSubtract == Long.MIN_VALUE ? plusSeconds(Long.MAX_VALUE).plusSeconds(1) : plusSeconds(-secondsToSubtract));
 664     }
 665 
 666     /**
 667      * Returns a copy of this duration with the specified duration in milliseconds subtracted.
 668      * <p>
 669      * This instance is immutable and unaffected by this method call.
 670      *
 671      * @param millisToSubtract  the milliseconds to subtract, positive or negative
 672      * @return a {@code Duration} based on this duration with the specified milliseconds subtracted, not null
 673      * @throws ArithmeticException if numeric overflow occurs


 699      * @return a {@code Duration} based on this duration multiplied by the specified scalar, not null
 700      * @throws ArithmeticException if numeric overflow occurs
 701      */
 702     public Duration multipliedBy(long multiplicand) {
 703         if (multiplicand == 0) {
 704             return ZERO;
 705         }
 706         if (multiplicand == 1) {
 707             return this;
 708         }
 709         return create(toSeconds().multiply(BigDecimal.valueOf(multiplicand)));
 710      }
 711 
 712     /**
 713      * Returns a copy of this duration divided by the specified value.
 714      * <p>
 715      * This instance is immutable and unaffected by this method call.
 716      *
 717      * @param divisor  the value to divide the duration by, positive or negative, not zero
 718      * @return a {@code Duration} based on this duration divided by the specified divisor, not null
 719      * @throws ArithmeticException if the divisor is zero
 720      * @throws ArithmeticException if numeric overflow occurs
 721      */
 722     public Duration dividedBy(long divisor) {
 723         if (divisor == 0) {
 724             throw new ArithmeticException("Cannot divide by zero");
 725         }
 726         if (divisor == 1) {
 727             return this;
 728         }
 729         return create(toSeconds().divide(BigDecimal.valueOf(divisor), RoundingMode.DOWN));
 730      }
 731 
 732     /**
 733      * Converts this duration to the total length in seconds and
 734      * fractional nanoseconds expressed as a {@code BigDecimal}.
 735      *
 736      * @return the total length of the duration in seconds, with a scale of 9, not null
 737      */
 738     private BigDecimal toSeconds() {
 739         return BigDecimal.valueOf(seconds).add(BigDecimal.valueOf(nanos, 9));
 740     }


 777      * This method returns a positive duration by effectively removing the sign from any negative total length.
 778      * For example, {@code PT-1.3S} will be returned as {@code PT1.3S}.
 779      * <p>
 780      * This instance is immutable and unaffected by this method call.
 781      *
 782      * @return a {@code Duration} based on this duration with an absolute length, not null
 783      * @throws ArithmeticException if numeric overflow occurs
 784      */
 785     public Duration abs() {
 786         return isNegative() ? negated() : this;
 787     }
 788 
 789     //-------------------------------------------------------------------------
 790     /**
 791      * Adds this duration to the specified temporal object.
 792      * <p>
 793      * This returns a temporal object of the same observable type as the input
 794      * with this duration added.
 795      * <p>
 796      * In most cases, it is clearer to reverse the calling pattern by using
 797      * {@link Temporal#plus(TemporalAdder)}.
 798      * <pre>
 799      *   // these two lines are equivalent, but the second approach is recommended
 800      *   dateTime = thisDuration.addTo(dateTime);
 801      *   dateTime = dateTime.plus(thisDuration);
 802      * </pre>
 803      * <p>
 804      * A {@code Duration} can only be added to a {@code Temporal} that
 805      * represents an instant and can supply {@link ChronoField#INSTANT_SECONDS}.
 806      * <p>
 807      * This instance is immutable and unaffected by this method call.
 808      *
 809      * @param temporal  the temporal object to adjust, not null
 810      * @return an object of the same type with the adjustment made, not null
 811      * @throws DateTimeException if unable to add
 812      * @throws ArithmeticException if numeric overflow occurs
 813      */
 814     @Override
 815     public Temporal addTo(Temporal temporal) {
 816         long instantSecs = temporal.getLong(INSTANT_SECONDS);
 817         long instantNanos = temporal.getLong(NANO_OF_SECOND);
 818         instantSecs = Math.addExact(instantSecs, seconds);
 819         instantNanos = Math.addExact(instantNanos, nanos);
 820         instantSecs = Math.addExact(instantSecs, Math.floorDiv(instantNanos, NANOS_PER_SECOND));
 821         instantNanos = Math.floorMod(instantNanos, NANOS_PER_SECOND);
 822         return temporal.with(INSTANT_SECONDS, instantSecs).with(NANO_OF_SECOND, instantNanos);
 823     }
 824 
 825     /**
 826      * Subtracts this duration from the specified temporal object.
 827      * <p>
 828      * This returns a temporal object of the same observable type as the input
 829      * with this duration subtracted.
 830      * <p>
 831      * In most cases, it is clearer to reverse the calling pattern by using
 832      * {@link Temporal#minus(TemporalSubtractor)}.
 833      * <pre>
 834      *   // these two lines are equivalent, but the second approach is recommended
 835      *   dateTime = thisDuration.subtractFrom(dateTime);
 836      *   dateTime = dateTime.minus(thisDuration);
 837      * </pre>
 838      * <p>
 839      * A {@code Duration} can only be subtracted from a {@code Temporal} that
 840      * represents an instant and can supply {@link ChronoField#INSTANT_SECONDS}.
 841      * <p>
 842      * This instance is immutable and unaffected by this method call.
 843      *
 844      * @param temporal  the temporal object to adjust, not null
 845      * @return an object of the same type with the adjustment made, not null
 846      * @throws DateTimeException if unable to subtract
 847      * @throws ArithmeticException if numeric overflow occurs
 848      */
 849     @Override
 850     public Temporal subtractFrom(Temporal temporal) {
 851         long instantSecs = temporal.getLong(INSTANT_SECONDS);
 852         long instantNanos = temporal.getLong(NANO_OF_SECOND);
 853         instantSecs = Math.subtractExact(instantSecs, seconds);
 854         instantNanos = Math.subtractExact(instantNanos, nanos);
 855         instantSecs = Math.addExact(instantSecs, Math.floorDiv(instantNanos, NANOS_PER_SECOND));
 856         instantNanos = Math.floorMod(instantNanos, NANOS_PER_SECOND);
 857         return temporal.with(INSTANT_SECONDS, instantSecs).with(NANO_OF_SECOND, instantNanos);
 858     }
 859 
 860     //-----------------------------------------------------------------------
 861     /**











































 862      * Converts this duration to the total length in milliseconds.
 863      * <p>
 864      * If this duration is too large to fit in a {@code long} milliseconds, then an
 865      * exception is thrown.
 866      * <p>
 867      * If this duration has greater than millisecond precision, then the conversion
 868      * will drop any excess precision information as though the amount in nanoseconds
 869      * was subject to integer division by one million.
 870      *
 871      * @return the total length of the duration in milliseconds
 872      * @throws ArithmeticException if numeric overflow occurs
 873      */
 874     public long toMillis() {
 875         long millis = Math.multiplyExact(seconds, 1000);
 876         millis = Math.addExact(millis, nanos / 1000_000);
 877         return millis;
 878     }
 879 
 880     /**
 881      * Converts this duration to the total length in nanoseconds expressed as a {@code long}.
 882      * <p>
 883      * If this duration is too large to fit in a {@code long} nanoseconds, then an
 884      * exception is thrown.
 885      *
 886      * @return the total length of the duration in nanoseconds
 887      * @throws ArithmeticException if numeric overflow occurs
 888      */
 889     public long toNanos() {
 890         long millis = Math.multiplyExact(seconds, 1000_000_000);
 891         millis = Math.addExact(millis, nanos);
 892         return millis;
 893     }
 894 
 895     //-----------------------------------------------------------------------
 896     /**
 897      * Compares this duration to the specified {@code Duration}.
 898      * <p>
 899      * The comparison is based on the total length of the durations.
 900      * It is "consistent with equals", as defined by {@link Comparable}.
 901      *
 902      * @param otherDuration  the other duration to compare to, not null
 903      * @return the comparator value, negative if less, positive if greater
 904      */
 905     @Override
 906     public int compareTo(Duration otherDuration) {
 907         int cmp = Long.compare(seconds, otherDuration.seconds);
 908         if (cmp != 0) {
 909             return cmp;
 910         }
 911         return nanos - otherDuration.nanos;
 912     }
 913 
 914     /**
 915      * Checks if this duration is greater than the specified {@code Duration}.
 916      * <p>
 917      * The comparison is based on the total length of the durations.
 918      *
 919      * @param otherDuration  the other duration to compare to, not null
 920      * @return true if this duration is greater than the specified duration
 921      */
 922     public boolean isGreaterThan(Duration otherDuration) {
 923         return compareTo(otherDuration) > 0;
 924     }
 925 
 926     /**
 927      * Checks if this duration is less than the specified {@code Duration}.
 928      * <p>
 929      * The comparison is based on the total length of the durations.
 930      *
 931      * @param otherDuration  the other duration to compare to, not null
 932      * @return true if this duration is less than the specified duration
 933      */
 934     public boolean isLessThan(Duration otherDuration) {
 935         return compareTo(otherDuration) < 0;
 936     }
 937 
 938     //-----------------------------------------------------------------------
 939     /**
 940      * Checks if this duration is equal to the specified {@code Duration}.
 941      * <p>
 942      * The comparison is based on the total length of the durations.
 943      *
 944      * @param otherDuration  the other duration, null returns false
 945      * @return true if the other duration is equal to this one
 946      */
 947     @Override
 948     public boolean equals(Object otherDuration) {
 949         if (this == otherDuration) {
 950             return true;
 951         }
 952         if (otherDuration instanceof Duration) {
 953             Duration other = (Duration) otherDuration;
 954             return this.seconds == other.seconds &&
 955                    this.nanos == other.nanos;
 956         }
 957         return false;
 958     }
 959 
 960     /**
 961      * A hash code for this duration.
 962      *
 963      * @return a suitable hash code
 964      */
 965     @Override
 966     public int hashCode() {
 967         return ((int) (seconds ^ (seconds >>> 32))) + (51 * nanos);
 968     }
 969 
 970     //-----------------------------------------------------------------------
 971     /**
 972      * A string representation of this duration using ISO-8601 seconds
 973      * based representation, such as {@code PT12.345S}.
 974      * <p>
 975      * The format of the returned string will be {@code PTnS} where n is
 976      * the seconds and fractional seconds of the duration.













 977      *
 978      * @return an ISO-8601 representation of this duration, not null
 979      */
 980     @Override
 981     public String toString() {






 982         StringBuilder buf = new StringBuilder(24);
 983         buf.append("PT");
 984         if (seconds < 0 && nanos > 0) {
 985             if (seconds == -1) {









 986                 buf.append("-0");
 987             } else {
 988                 buf.append(seconds + 1);
 989             }
 990         } else {
 991             buf.append(seconds);
 992         }
 993         if (nanos > 0) {
 994             int pos = buf.length();
 995             if (seconds < 0) {
 996                 buf.append(2 * NANOS_PER_SECOND - nanos);
 997             } else {
 998                 buf.append(nanos + NANOS_PER_SECOND);
 999             }
1000             while (buf.charAt(buf.length() - 1) == '0') {
1001                 buf.setLength(buf.length() - 1);
1002             }
1003             buf.setCharAt(pos, '.');
1004         }
1005         buf.append('S');
1006         return buf.toString();
1007     }
1008 
1009     //-----------------------------------------------------------------------
1010     /**
1011      * Writes the object using a
1012      * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1013      * <pre>
1014      *  out.writeByte(1);  // identifies this as a Duration
1015      *  out.writeLong(seconds);




  44  *    and/or other materials provided with the distribution.
  45  *
  46  *  * Neither the name of JSR-310 nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  51  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  52  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  53  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  54  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  55  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  56  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  57  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  58  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  59  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  60  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  61  */
  62 package java.time;
  63 
  64 import static java.time.LocalTime.NANOS_PER_SECOND;
  65 import static java.time.LocalTime.SECONDS_PER_DAY;
  66 import static java.time.LocalTime.SECONDS_PER_HOUR;
  67 import static java.time.LocalTime.SECONDS_PER_MINUTE;
  68 import static java.time.temporal.ChronoField.NANO_OF_SECOND;
  69 import static java.time.temporal.ChronoUnit.DAYS;
  70 import static java.time.temporal.ChronoUnit.NANOS;
  71 import static java.time.temporal.ChronoUnit.SECONDS;
  72 
  73 import java.io.DataInput;
  74 import java.io.DataOutput;
  75 import java.io.IOException;
  76 import java.io.InvalidObjectException;
  77 import java.io.ObjectStreamException;
  78 import java.io.Serializable;
  79 import java.math.BigDecimal;
  80 import java.math.BigInteger;
  81 import java.math.RoundingMode;
  82 import java.time.format.DateTimeParseException;
  83 import java.time.temporal.ChronoField;
  84 import java.time.temporal.ChronoUnit;
  85 import java.time.temporal.Temporal;
  86 import java.time.temporal.TemporalAmount;


  87 import java.time.temporal.TemporalUnit;
  88 import java.util.Arrays;
  89 import java.util.Collections;
  90 import java.util.List;
  91 import java.util.Objects;
  92 import java.util.regex.Matcher;
  93 import java.util.regex.Pattern;
  94 
  95 /**
  96  * A time-based amount of time, such as '34.5 seconds'.
  97  * <p>
  98  * This class models a quantity or amount of time in terms of seconds and nanoseconds.
  99  * It can be accessed using other duration-based units, such as minutes and hours.
 100  * In addition, the {@link ChronoUnit#DAYS DAYS} unit can be used and is treated as
 101  * exactly equal to 24 hours, thus ignoring daylight savings effects.
 102  * See {@link Period} for the date-based equivalent to this class.
 103  * <p>
 104  * A physical duration could be of infinite length.
 105  * For practicality, the duration is stored with constraints similar to {@link Instant}.
 106  * The duration uses nanosecond resolution with a maximum value of the seconds that can
 107  * be held in a {@code long}. This is greater than the current estimated age of the universe.
 108  * <p>
 109  * The range of a duration requires the storage of a number larger than a {@code long}.
 110  * To achieve this, the class stores a {@code long} representing seconds and an {@code int}
 111  * representing nanosecond-of-second, which will always be between 0 and 999,999,999.
 112  * The model is of a directed duration, meaning that the duration may be negative.
 113  * <p>
 114  * The duration is measured in "seconds", but these are not necessarily identical to
 115  * the scientific "SI second" definition based on atomic clocks.
 116  * This difference only impacts durations measured near a leap-second and should not affect
 117  * most applications.
 118  * See {@link Instant} for a discussion as to the meaning of the second and time-scales.
 119  *
 120  * <h3>Specification for implementors</h3>
 121  * This class is immutable and thread-safe.
 122  *
 123  * @since 1.8
 124  */
 125 public final class Duration
 126         implements TemporalAmount, Comparable<Duration>, Serializable {
 127 
 128     /**
 129      * Constant for a duration of zero.
 130      */
 131     public static final Duration ZERO = new Duration(0, 0);
 132     /**
 133      * Serialization version.
 134      */
 135     private static final long serialVersionUID = 3078945930695997490L;
 136     /**
 137      * Constant for nanos per second.
 138      */
 139     private static final BigInteger BI_NANOS_PER_SECOND = BigInteger.valueOf(NANOS_PER_SECOND);
 140     /**
 141      * The pattern for parsing.
 142      */
 143     private final static Pattern PATTERN =
 144             Pattern.compile("([-+]?)P(?:([-+]?[0-9]+)D)?" +
 145                     "(T(?:([-+]?[0-9]+)H)?(?:([-+]?[0-9]+)M)?(?:([-+]?[0-9]+)(?:[.,]([0-9]{0,9}))?S)?)?",
 146                     Pattern.CASE_INSENSITIVE);
 147 
 148     /**
 149      * The number of seconds in the duration.
 150      */
 151     private final long seconds;
 152     /**
 153      * The number of nanoseconds in the duration, expressed as a fraction of the
 154      * number of seconds. This is always positive, and never exceeds 999,999,999.
 155      */
 156     private final int nanos;
 157 
 158     //-----------------------------------------------------------------------
 159     /**
 160      * Obtains a {@code Duration} representing a number of standard 24 hour days.
 161      * <p>
 162      * The seconds are calculated based on the standard definition of a day,
 163      * where each day is 86400 seconds which implies a 24 hour day.
 164      * The nanosecond in second field is set to zero.
 165      *
 166      * @param days  the number of days, positive or negative
 167      * @return a {@code Duration}, not null
 168      * @throws ArithmeticException if the input days exceeds the capacity of {@code Duration}
 169      */
 170     public static Duration ofDays(long days) {
 171         return create(Math.multiplyExact(days, SECONDS_PER_DAY), 0);
 172     }
 173 
 174     /**
 175      * Obtains a {@code Duration} representing a number of standard hours.
 176      * <p>
 177      * The seconds are calculated based on the standard definition of an hour,
 178      * where each hour is 3600 seconds.
 179      * The nanosecond in second field is set to zero.
 180      *
 181      * @param hours  the number of hours, positive or negative
 182      * @return a {@code Duration}, not null
 183      * @throws ArithmeticException if the input hours exceeds the capacity of {@code Duration}
 184      */
 185     public static Duration ofHours(long hours) {
 186         return create(Math.multiplyExact(hours, SECONDS_PER_HOUR), 0);
 187     }
 188 
 189     /**
 190      * Obtains a {@code Duration} representing a number of standard minutes.
 191      * <p>
 192      * The seconds are calculated based on the standard definition of a minute,
 193      * where each minute is 60 seconds.
 194      * The nanosecond in second field is set to zero.
 195      *
 196      * @param minutes  the number of minutes, positive or negative
 197      * @return a {@code Duration}, not null
 198      * @throws ArithmeticException if the input minutes exceeds the capacity of {@code Duration}
 199      */
 200     public static Duration ofMinutes(long minutes) {
 201         return create(Math.multiplyExact(minutes, SECONDS_PER_MINUTE), 0);
 202     }
 203 
 204     //-----------------------------------------------------------------------
 205     /**
 206      * Obtains a {@code Duration} representing a number of seconds.
 207      * <p>
 208      * The nanosecond in second field is set to zero.
 209      *
 210      * @param seconds  the number of seconds, positive or negative
 211      * @return a {@code Duration}, not null
 212      */
 213     public static Duration ofSeconds(long seconds) {
 214         return create(seconds, 0);
 215     }
 216 
 217     /**
 218      * Obtains a {@code Duration} representing a number of seconds and an
 219      * adjustment in nanoseconds.
 220      * <p>
 221      * This method allows an arbitrary number of nanoseconds to be passed in.
 222      * The factory will alter the values of the second and nanosecond in order
 223      * to ensure that the stored nanosecond is in the range 0 to 999,999,999.
 224      * For example, the following will result in the exactly the same duration:
 225      * <pre>
 226      *  Duration.ofSeconds(3, 1);
 227      *  Duration.ofSeconds(4, -999_999_999);
 228      *  Duration.ofSeconds(2, 1000_000_001);
 229      * </pre>
 230      *
 231      * @param seconds  the number of seconds, positive or negative
 232      * @param nanoAdjustment  the nanosecond adjustment to the number of seconds, positive or negative
 233      * @return a {@code Duration}, not null
 234      * @throws ArithmeticException if the adjustment causes the seconds to exceed the capacity of {@code Duration}
 235      */
 236     public static Duration ofSeconds(long seconds, long nanoAdjustment) {
 237         long secs = Math.addExact(seconds, Math.floorDiv(nanoAdjustment, NANOS_PER_SECOND));
 238         int nos = (int) Math.floorMod(nanoAdjustment, NANOS_PER_SECOND);
 239         return create(secs, nos);
 240     }
 241 
 242     //-----------------------------------------------------------------------
 243     /**
 244      * Obtains a {@code Duration} representing a number of milliseconds.
 245      * <p>
 246      * The seconds and nanoseconds are extracted from the specified milliseconds.
 247      *
 248      * @param millis  the number of milliseconds, positive or negative
 249      * @return a {@code Duration}, not null
 250      */
 251     public static Duration ofMillis(long millis) {
 252         long secs = millis / 1000;
 253         int mos = (int) (millis % 1000);
 254         if (mos < 0) {
 255             mos += 1000;
 256             secs--;
 257         }
 258         return create(secs, mos * 1000_000);
 259     }
 260 
 261     //-----------------------------------------------------------------------
 262     /**
 263      * Obtains a {@code Duration} representing a number of nanoseconds.
 264      * <p>
 265      * The seconds and nanoseconds are extracted from the specified nanoseconds.
 266      *
 267      * @param nanos  the number of nanoseconds, positive or negative
 268      * @return a {@code Duration}, not null
 269      */
 270     public static Duration ofNanos(long nanos) {
 271         long secs = nanos / NANOS_PER_SECOND;
 272         int nos = (int) (nanos % NANOS_PER_SECOND);
 273         if (nos < 0) {
 274             nos += NANOS_PER_SECOND;
 275             secs--;
 276         }
 277         return create(secs, nos);
 278     }
 279 
 280     //-----------------------------------------------------------------------
 281     /**
 282      * Obtains a {@code Duration} representing an amount in the specified unit.














































 283      * <p>
 284      * The parameters represent the two parts of a phrase like '6 Hours'. For example:
 285      * <pre>
 286      *  Duration.of(3, SECONDS);
 287      *  Duration.of(465, HOURS);
 288      * </pre>
 289      * Only a subset of units are accepted by this method.
 290      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 291      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 292      *
 293      * @param amount  the amount of the duration, measured in terms of the unit, positive or negative
 294      * @param unit  the unit that the duration is measured in, must have an exact duration, not null
 295      * @return a {@code Duration}, not null
 296      * @throws DateTimeException if the period unit has an estimated duration
 297      * @throws ArithmeticException if a numeric overflow occurs
 298      */
 299     public static Duration of(long amount, TemporalUnit unit) {
 300         return ZERO.plus(amount, unit);
 301     }
 302 
 303     //-----------------------------------------------------------------------
 304     /**
 305      * Obtains a {@code Duration} representing the duration between two instants.
 306      * <p>
 307      * This calculates the duration between two temporal objects of the same type.
 308      * The difference in seconds is calculated using
 309      * {@link Temporal#periodUntil(Temporal, TemporalUnit)}.
 310      * The difference in nanoseconds is calculated using by querying the
 311      * {@link ChronoField#NANO_OF_SECOND NANO_OF_SECOND} field.
 312      * <p>
 313      * The result of this method can be a negative period if the end is before the start.
 314      * To guarantee to obtain a positive duration call {@link #abs()} on the result.
 315      *
 316      * @param startInclusive  the start instant, inclusive, not null
 317      * @param endExclusive  the end instant, exclusive, not null
 318      * @return a {@code Duration}, not null
 319      * @throws ArithmeticException if the calculation exceeds the capacity of {@code Duration}
 320      */
 321     public static  Duration between(Temporal startInclusive, Temporal endExclusive) {
 322         long secs = startInclusive.periodUntil(endExclusive, SECONDS);
 323         long nanos;
 324         try {
 325             nanos = endExclusive.getLong(NANO_OF_SECOND) - startInclusive.getLong(NANO_OF_SECOND);
 326         } catch (DateTimeException ex) {
 327             nanos = 0;
 328         }
 329         return ofSeconds(secs, nanos);
 330     }
 331 
 332     //-----------------------------------------------------------------------
 333     /**
 334      * Obtains a {@code Duration} from a text string such as {@code PnDTnHnMn.nS}.
 335      * <p>
 336      * This will parse a textual representation of a duration, including the
 337      * string produced by {@code toString()}. The formats accepted are based
 338      * on the ISO-8601 duration format {@code PnDTnHnMn.nS} with days
 339      * considered to be exactly 24 hours.
 340      * <p>
 341      * The string starts with an optional sign, denoted by the ASCII negative
 342      * or positive symbol. If negative, the whole period is negated.
 343      * The ASCII letter "P" is next in upper or lower case.
 344      * There are then four sections, each consisting of a number and a suffix.
 345      * The sections have suffixes in ASCII of "D", "H", "M" and "S" for
 346      * days, hours, minutes and seconds, accepted in upper or lower case.
 347      * The suffixes must occur in order. The ASCII letter "T" must occur before
 348      * the first occurrence, if any, of an hour, minute or second section.
 349      * At least one of the four sections must be present, and if "T" is present
 350      * there must be at least one section after the "T".
 351      * The number part of each section must consist of one or more ASCII digits.
 352      * The number may be prefixed by the ASCII negative or positive symbol.
 353      * The number of days, hours and minutes must parse to an {@code long}.
 354      * The number of seconds must parse to an {@code long} with optional fraction.
 355      * The decimal point may be either a dot or a comma.
 356      * The fractional part may have from zero to 9 digits.
 357      * <p>
 358      * The leading plus/minus sign, and negative values for other units are
 359      * not part of the ISO-8601 standard.
 360      * <p>
 361      * Examples:
 362      * <pre>
 363      *    "PT20.345S" -> parses as "20.345 seconds"
 364      *    "PT15M"     -> parses as "15 minutes" (where a minute is 60 seconds)
 365      *    "PT10H"     -> parses as "10 hours" (where an hour is 3600 seconds)
 366      *    "P2D"       -> parses as "2 days" (where a day is 24 hours or 86400 seconds)
 367      *    "P2DT3H4M"  -> parses as "2 days, 3 hours and 4 minutes"
 368      *    "P-6H3M"    -> parses as "-6 hours and +3 minutes"
 369      *    "-P6H3M"    -> parses as "-6 hours and -3 minutes"
 370      *    "-P-6H+3M"  -> parses as "+6 hours and -3 minutes"
 371      * </pre>
 372      *
 373      * @param text  the text to parse, not null
 374      * @return the parsed duration, not null
 375      * @throws DateTimeParseException if the text cannot be parsed to a duration
 376      */
 377     public static Duration parse(CharSequence text) {
 378         Objects.requireNonNull(text, "text");
 379         Matcher matcher = PATTERN.matcher(text);
 380         if (matcher.matches()) {
 381             // check for letter T but no time sections
 382             if ("T".equals(matcher.group(3)) == false) {
 383                 boolean negate = "-".equals(matcher.group(1));
 384                 String dayMatch = matcher.group(2);
 385                 String hourMatch = matcher.group(4);
 386                 String minuteMatch = matcher.group(5);
 387                 String secondMatch = matcher.group(6);
 388                 String fractionMatch = matcher.group(7);
 389                 if (dayMatch != null || hourMatch != null || minuteMatch != null || secondMatch != null) {
 390                     long daysAsSecs = parseNumber(text, dayMatch, SECONDS_PER_DAY, "days");
 391                     long hoursAsSecs = parseNumber(text, hourMatch, SECONDS_PER_HOUR, "hours");
 392                     long minsAsSecs = parseNumber(text, minuteMatch, SECONDS_PER_MINUTE, "minutes");
 393                     long seconds = parseNumber(text, secondMatch, 1, "seconds");
 394                     int nanos = parseFraction(text,  fractionMatch, seconds < 0 ? -1 : 1);
 395                     try {
 396                         return create(negate, daysAsSecs, hoursAsSecs, minsAsSecs, seconds, nanos);
 397                     } catch (ArithmeticException ex) {
 398                         throw (DateTimeParseException) new DateTimeParseException("Text cannot be parsed to a Duration: overflow", text, 0).initCause(ex);
 399                     }
 400                 }
 401             }
 402         }
 403         throw new DateTimeParseException("Text cannot be parsed to a Duration", text, 0);
 404     }
 405 
 406     private static long parseNumber(CharSequence text, String parsed, int multiplier, String errorText) {
 407         // regex limits to [-+]?[0-9]+
 408         if (parsed == null) {
 409             return 0;
 410         }
 411         try {
 412             long val = Long.parseLong(parsed);
 413             return Math.multiplyExact(val, multiplier);
 414         } catch (NumberFormatException | ArithmeticException ex) {
 415             throw (DateTimeParseException) new DateTimeParseException("Text cannot be parsed to a Duration: " + errorText, text, 0).initCause(ex);
 416         }
 417     }
 418 
 419     private static int parseFraction(CharSequence text, String parsed, int negate) {
 420         // regex limits to [0-9]{0,9}
 421         if (parsed == null || parsed.length() == 0) {
 422             return 0;
 423         }

 424         try {
 425             parsed = (parsed + "000000000").substring(0, 9);
 426             return Integer.parseInt(parsed) * negate;
 427         } catch (NumberFormatException | ArithmeticException ex) {
 428             throw (DateTimeParseException) new DateTimeParseException("Text cannot be parsed to a Duration: fraction", text, 0).initCause(ex);
 429         }







































 430     }

 431 
 432     private static Duration create(boolean negate, long daysAsSecs, long hoursAsSecs, long minsAsSecs, long secs, int nanos) {
 433         long seconds = Math.addExact(daysAsSecs, Math.addExact(hoursAsSecs, Math.addExact(minsAsSecs, secs)));
 434         if (negate) {
 435             return ofSeconds(seconds, nanos).negated();
 436         }
 437         return ofSeconds(seconds, nanos);
 438     }
 439 
 440     //-----------------------------------------------------------------------
 441     /**
 442      * Obtains an instance of {@code Duration} using seconds and nanoseconds.
 443      *
 444      * @param seconds  the length of the duration in seconds, positive or negative
 445      * @param nanoAdjustment  the nanosecond adjustment within the second, from 0 to 999,999,999
 446      */
 447     private static Duration create(long seconds, int nanoAdjustment) {
 448         if ((seconds | nanoAdjustment) == 0) {
 449             return ZERO;
 450         }
 451         return new Duration(seconds, nanoAdjustment);
 452     }
 453 
 454     /**
 455      * Constructs an instance of {@code Duration} using seconds and nanoseconds.
 456      *
 457      * @param seconds  the length of the duration in seconds, positive or negative
 458      * @param nanos  the nanoseconds within the second, from 0 to 999,999,999
 459      */
 460     private Duration(long seconds, int nanos) {
 461         super();
 462         this.seconds = seconds;
 463         this.nanos = nanos;
 464     }
 465 
 466     //-----------------------------------------------------------------------
 467     /**
 468      * Gets the value of the requested unit.
 469      * <p>
 470      * This returns a value for each of the two supported units,
 471      * {@link ChronoUnit#SECONDS SECONDS} and {@link ChronoUnit#NANOS NANOS}.
 472      * All other units throw an exception.
 473      *
 474      * @param unit the {@code TemporalUnit} for which to return the value
 475      * @return the long value of the unit
 476      * @throws DateTimeException if the unit is not supported
 477      */
 478     @Override
 479     public long get(TemporalUnit unit) {
 480         if (unit == SECONDS) {
 481             return seconds;
 482         } else if (unit == NANOS) {
 483             return nanos;
 484         } else {
 485             throw new DateTimeException("Unsupported unit: " + unit.getName());
 486         }
 487     }
 488 
 489     /**
 490      * Gets the set of units supported by this duration.
 491      * <p>
 492      * The supported units are {@link ChronoUnit#SECONDS SECONDS},
 493      * and {@link ChronoUnit#NANOS NANOS}.
 494      * They are returned in the order seconds, nanos.
 495      * <p>
 496      * This set can be used in conjunction with {@link #get(TemporalUnit)}
 497      * to access the entire state of the period.
 498      *
 499      * @return a list containing the seconds and nanos units, not null
 500      */
 501     @Override
 502     public List<TemporalUnit> getUnits() {
 503         return DurationUnits.UNITS;
 504     }
 505 
 506     /**
 507      * Private class to delay initialization of this list until needed.
 508      * The circular dependency between Duration and ChronoUnit prevents
 509      * the simple initialization in Duration.
 510      */
 511     private static class DurationUnits {
 512         final static List<TemporalUnit> UNITS =
 513                 Collections.unmodifiableList(Arrays.<TemporalUnit>asList(SECONDS, NANOS));
 514     }
 515 
 516     //-----------------------------------------------------------------------
 517     /**
 518      * Checks if this duration is zero length.
 519      * <p>
 520      * A {@code Duration} represents a directed distance between two points on
 521      * the time-line and can therefore be positive, zero or negative.
 522      * This method checks whether the length is zero.
 523      *
 524      * @return true if this duration has a total length equal to zero
 525      */
 526     public boolean isZero() {
 527         return (seconds | nanos) == 0;
 528     }
 529 
 530     /**
 531      * Checks if this duration is negative, excluding zero.
 532      * <p>
 533      * A {@code Duration} represents a directed distance between two points on
 534      * the time-line and can therefore be positive, zero or negative.
 535      * This method checks whether the length is less than zero.
 536      *
 537      * @return true if this duration has a total length less than zero
 538      */
 539     public boolean isNegative() {
 540         return seconds < 0;
 541     }
 542 
 543     //-----------------------------------------------------------------------
 544     /**
 545      * Gets the number of seconds in this duration.
 546      * <p>
 547      * The length of the duration is stored using two fields - seconds and nanoseconds.


 562     /**
 563      * Gets the number of nanoseconds within the second in this duration.
 564      * <p>
 565      * The length of the duration is stored using two fields - seconds and nanoseconds.
 566      * The nanoseconds part is a value from 0 to 999,999,999 that is an adjustment to
 567      * the length in seconds.
 568      * The total duration is defined by calling this method and {@link #getSeconds()}.
 569      * <p>
 570      * A {@code Duration} represents a directed distance between two points on the time-line.
 571      * A negative duration is expressed by the negative sign of the seconds part.
 572      * A duration of -1 nanosecond is stored as -1 seconds plus 999,999,999 nanoseconds.
 573      *
 574      * @return the nanoseconds within the second part of the length of the duration, from 0 to 999,999,999
 575      */
 576     public int getNano() {
 577         return nanos;
 578     }
 579 
 580     //-----------------------------------------------------------------------
 581     /**
 582      * Returns a copy of this duration with the specified amount of seconds.
 583      * <p>
 584      * This returns a duration with the specified seconds, retaining the
 585      * nano-of-second part of this duration.
 586      * <p>
 587      * This instance is immutable and unaffected by this method call.
 588      *
 589      * @param seconds  the seconds to represent, may be negative
 590      * @return a {@code Duration} based on this period with the requested seconds, not null
 591      */
 592     public Duration withSeconds(long seconds) {
 593         return create(seconds, nanos);
 594     }
 595 
 596     /**
 597      * Returns a copy of this duration with the specified nano-of-second.
 598      * <p>
 599      * This returns a duration with the specified nano-of-second, retaining the
 600      * seconds part of this duration.
 601      * <p>
 602      * This instance is immutable and unaffected by this method call.
 603      *
 604      * @param nanoOfSecond  the nano-of-second to represent, from 0 to 999,999,999
 605      * @return a {@code Duration} based on this period with the requested nano-of-second, not null
 606      * @throws DateTimeException if the nano-of-second is invalid
 607      */
 608     public Duration withNanos(int nanoOfSecond) {
 609         NANO_OF_SECOND.checkValidIntValue(nanoOfSecond);
 610         return create(seconds, nanoOfSecond);
 611     }
 612 
 613     //-----------------------------------------------------------------------
 614     /**
 615      * Returns a copy of this duration with the specified duration added.
 616      * <p>
 617      * This instance is immutable and unaffected by this method call.
 618      *
 619      * @param duration  the duration to add, positive or negative, not null
 620      * @return a {@code Duration} based on this duration with the specified duration added, not null
 621      * @throws ArithmeticException if numeric overflow occurs
 622      */
 623     public Duration plus(Duration duration) {
 624         return plus(duration.getSeconds(), duration.getNano());
 625      }
 626 
 627     /**
 628      * Returns a copy of this duration with the specified duration added.
 629      * <p>
 630      * The duration amount is measured in terms of the specified unit.
 631      * Only a subset of units are accepted by this method.
 632      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 633      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 634      * <p>


 648             throw new DateTimeException("Unit must not have an estimated duration");
 649         }
 650         if (amountToAdd == 0) {
 651             return this;
 652         }
 653         if (unit instanceof ChronoUnit) {
 654             switch ((ChronoUnit) unit) {
 655                 case NANOS: return plusNanos(amountToAdd);
 656                 case MICROS: return plusSeconds((amountToAdd / (1000_000L * 1000)) * 1000).plusNanos((amountToAdd % (1000_000L * 1000)) * 1000);
 657                 case MILLIS: return plusMillis(amountToAdd);
 658                 case SECONDS: return plusSeconds(amountToAdd);
 659             }
 660             return plusSeconds(Math.multiplyExact(unit.getDuration().seconds, amountToAdd));
 661         }
 662         Duration duration = unit.getDuration().multipliedBy(amountToAdd);
 663         return plusSeconds(duration.getSeconds()).plusNanos(duration.getNano());
 664     }
 665 
 666     //-----------------------------------------------------------------------
 667     /**
 668      * Returns a copy of this duration with the specified duration in standard 24 hour days added.
 669      * <p>
 670      * The number of days is multiplied by 86400 to obtain the number of seconds to add.
 671      * This is based on the standard definition of a day as 24 hours.
 672      * <p>
 673      * This instance is immutable and unaffected by this method call.
 674      *
 675      * @param daysToAdd  the days to add, positive or negative
 676      * @return a {@code Duration} based on this duration with the specified days added, not null
 677      * @throws ArithmeticException if numeric overflow occurs
 678      */
 679     public Duration plusDays(long daysToAdd) {
 680         return plus(Math.multiplyExact(daysToAdd, SECONDS_PER_DAY), 0);
 681     }
 682 
 683     /**
 684      * Returns a copy of this duration with the specified duration in hours added.
 685      * <p>
 686      * This instance is immutable and unaffected by this method call.
 687      *
 688      * @param hoursToAdd  the hours to add, positive or negative
 689      * @return a {@code Duration} based on this duration with the specified hours added, not null
 690      * @throws ArithmeticException if numeric overflow occurs
 691      */
 692     public Duration plusHours(long hoursToAdd) {
 693         return plus(Math.multiplyExact(hoursToAdd, SECONDS_PER_HOUR), 0);
 694     }
 695 
 696     /**
 697      * Returns a copy of this duration with the specified duration in minutes added.
 698      * <p>
 699      * This instance is immutable and unaffected by this method call.
 700      *
 701      * @param minutesToAdd  the minutes to add, positive or negative
 702      * @return a {@code Duration} based on this duration with the specified minutes added, not null
 703      * @throws ArithmeticException if numeric overflow occurs
 704      */
 705     public Duration plusMinutes(long minutesToAdd) {
 706         return plus(Math.multiplyExact(minutesToAdd, SECONDS_PER_MINUTE), 0);
 707     }
 708 
 709     /**
 710      * Returns a copy of this duration with the specified duration in seconds added.
 711      * <p>
 712      * This instance is immutable and unaffected by this method call.
 713      *
 714      * @param secondsToAdd  the seconds to add, positive or negative
 715      * @return a {@code Duration} based on this duration with the specified seconds added, not null
 716      * @throws ArithmeticException if numeric overflow occurs
 717      */
 718     public Duration plusSeconds(long secondsToAdd) {
 719         return plus(secondsToAdd, 0);
 720     }
 721 
 722     /**
 723      * Returns a copy of this duration with the specified duration in milliseconds added.
 724      * <p>
 725      * This instance is immutable and unaffected by this method call.
 726      *
 727      * @param millisToAdd  the milliseconds to add, positive or negative
 728      * @return a {@code Duration} based on this duration with the specified milliseconds added, not null
 729      * @throws ArithmeticException if numeric overflow occurs


 789      * Returns a copy of this duration with the specified duration subtracted.
 790      * <p>
 791      * The duration amount is measured in terms of the specified unit.
 792      * Only a subset of units are accepted by this method.
 793      * The unit must either have an {@linkplain TemporalUnit#isDurationEstimated() exact duration} or
 794      * be {@link ChronoUnit#DAYS} which is treated as 24 hours. Other units throw an exception.
 795      * <p>
 796      * This instance is immutable and unaffected by this method call.
 797      *
 798      * @param amountToSubtract  the amount of the period, measured in terms of the unit, positive or negative
 799      * @param unit  the unit that the period is measured in, must have an exact duration, not null
 800      * @return a {@code Duration} based on this duration with the specified duration subtracted, not null
 801      * @throws ArithmeticException if numeric overflow occurs
 802      */
 803     public Duration minus(long amountToSubtract, TemporalUnit unit) {
 804         return (amountToSubtract == Long.MIN_VALUE ? plus(Long.MAX_VALUE, unit).plus(1, unit) : plus(-amountToSubtract, unit));
 805     }
 806 
 807     //-----------------------------------------------------------------------
 808     /**
 809      * Returns a copy of this duration with the specified duration in standard 24 hour days subtracted.
 810      * <p>
 811      * The number of days is multiplied by 86400 to obtain the number of seconds to subtract.
 812      * This is based on the standard definition of a day as 24 hours.
 813      * <p>
 814      * This instance is immutable and unaffected by this method call.
 815      *
 816      * @param daysToSubtract  the days to subtract, positive or negative
 817      * @return a {@code Duration} based on this duration with the specified days subtracted, not null
 818      * @throws ArithmeticException if numeric overflow occurs
 819      */
 820     public Duration minusDays(long daysToSubtract) {
 821         return (daysToSubtract == Long.MIN_VALUE ? plusDays(Long.MAX_VALUE).plusDays(1) : plusDays(-daysToSubtract));
 822     }
 823 
 824     /**
 825      * Returns a copy of this duration with the specified duration in hours subtracted.
 826      * <p>
 827      * The number of hours is multiplied by 3600 to obtain the number of seconds to subtract.
 828      * <p>
 829      * This instance is immutable and unaffected by this method call.
 830      *
 831      * @param hoursToSubtract  the hours to subtract, positive or negative
 832      * @return a {@code Duration} based on this duration with the specified hours subtracted, not null
 833      * @throws ArithmeticException if numeric overflow occurs
 834      */
 835     public Duration minusHours(long hoursToSubtract) {
 836         return (hoursToSubtract == Long.MIN_VALUE ? plusHours(Long.MAX_VALUE).plusHours(1) : plusHours(-hoursToSubtract));
 837     }
 838 
 839     /**
 840      * Returns a copy of this duration with the specified duration in minutes subtracted.
 841      * <p>
 842      * The number of hours is multiplied by 60 to obtain the number of seconds to subtract.
 843      * <p>
 844      * This instance is immutable and unaffected by this method call.
 845      *
 846      * @param minutesToSubtract  the minutes to subtract, positive or negative
 847      * @return a {@code Duration} based on this duration with the specified minutes subtracted, not null
 848      * @throws ArithmeticException if numeric overflow occurs
 849      */
 850     public Duration minusMinutes(long minutesToSubtract) {
 851         return (minutesToSubtract == Long.MIN_VALUE ? plusMinutes(Long.MAX_VALUE).plusMinutes(1) : plusMinutes(-minutesToSubtract));
 852     }
 853 
 854     /**
 855      * Returns a copy of this duration with the specified duration in seconds subtracted.
 856      * <p>
 857      * This instance is immutable and unaffected by this method call.
 858      *
 859      * @param secondsToSubtract  the seconds to subtract, positive or negative
 860      * @return a {@code Duration} based on this duration with the specified seconds subtracted, not null
 861      * @throws ArithmeticException if numeric overflow occurs
 862      */
 863     public Duration minusSeconds(long secondsToSubtract) {
 864         return (secondsToSubtract == Long.MIN_VALUE ? plusSeconds(Long.MAX_VALUE).plusSeconds(1) : plusSeconds(-secondsToSubtract));
 865     }
 866 
 867     /**
 868      * Returns a copy of this duration with the specified duration in milliseconds subtracted.
 869      * <p>
 870      * This instance is immutable and unaffected by this method call.
 871      *
 872      * @param millisToSubtract  the milliseconds to subtract, positive or negative
 873      * @return a {@code Duration} based on this duration with the specified milliseconds subtracted, not null
 874      * @throws ArithmeticException if numeric overflow occurs


 900      * @return a {@code Duration} based on this duration multiplied by the specified scalar, not null
 901      * @throws ArithmeticException if numeric overflow occurs
 902      */
 903     public Duration multipliedBy(long multiplicand) {
 904         if (multiplicand == 0) {
 905             return ZERO;
 906         }
 907         if (multiplicand == 1) {
 908             return this;
 909         }
 910         return create(toSeconds().multiply(BigDecimal.valueOf(multiplicand)));
 911      }
 912 
 913     /**
 914      * Returns a copy of this duration divided by the specified value.
 915      * <p>
 916      * This instance is immutable and unaffected by this method call.
 917      *
 918      * @param divisor  the value to divide the duration by, positive or negative, not zero
 919      * @return a {@code Duration} based on this duration divided by the specified divisor, not null
 920      * @throws ArithmeticException if the divisor is zero or if numeric overflow occurs

 921      */
 922     public Duration dividedBy(long divisor) {
 923         if (divisor == 0) {
 924             throw new ArithmeticException("Cannot divide by zero");
 925         }
 926         if (divisor == 1) {
 927             return this;
 928         }
 929         return create(toSeconds().divide(BigDecimal.valueOf(divisor), RoundingMode.DOWN));
 930      }
 931 
 932     /**
 933      * Converts this duration to the total length in seconds and
 934      * fractional nanoseconds expressed as a {@code BigDecimal}.
 935      *
 936      * @return the total length of the duration in seconds, with a scale of 9, not null
 937      */
 938     private BigDecimal toSeconds() {
 939         return BigDecimal.valueOf(seconds).add(BigDecimal.valueOf(nanos, 9));
 940     }


 977      * This method returns a positive duration by effectively removing the sign from any negative total length.
 978      * For example, {@code PT-1.3S} will be returned as {@code PT1.3S}.
 979      * <p>
 980      * This instance is immutable and unaffected by this method call.
 981      *
 982      * @return a {@code Duration} based on this duration with an absolute length, not null
 983      * @throws ArithmeticException if numeric overflow occurs
 984      */
 985     public Duration abs() {
 986         return isNegative() ? negated() : this;
 987     }
 988 
 989     //-------------------------------------------------------------------------
 990     /**
 991      * Adds this duration to the specified temporal object.
 992      * <p>
 993      * This returns a temporal object of the same observable type as the input
 994      * with this duration added.
 995      * <p>
 996      * In most cases, it is clearer to reverse the calling pattern by using
 997      * {@link Temporal#plus(TemporalAmount)}.
 998      * <pre>
 999      *   // these two lines are equivalent, but the second approach is recommended
1000      *   dateTime = thisDuration.addTo(dateTime);
1001      *   dateTime = dateTime.plus(thisDuration);
1002      * </pre>
1003      * <p>
1004      * The calculation will add the seconds, then nanos.
1005      * Only non-zero amounts will be added.
1006      * <p>
1007      * This instance is immutable and unaffected by this method call.
1008      *
1009      * @param temporal  the temporal object to adjust, not null
1010      * @return an object of the same type with the adjustment made, not null
1011      * @throws DateTimeException if unable to add
1012      * @throws ArithmeticException if numeric overflow occurs
1013      */
1014     @Override
1015     public Temporal addTo(Temporal temporal) {
1016         if (seconds != 0) {
1017             temporal = temporal.plus(seconds, SECONDS);
1018         }
1019         if (nanos != 0) {
1020             temporal = temporal.plus(nanos, NANOS);
1021         }
1022         return temporal;
1023     }
1024 
1025     /**
1026      * Subtracts this duration from the specified temporal object.
1027      * <p>
1028      * This returns a temporal object of the same observable type as the input
1029      * with this duration subtracted.
1030      * <p>
1031      * In most cases, it is clearer to reverse the calling pattern by using
1032      * {@link Temporal#minus(TemporalAmount)}.
1033      * <pre>
1034      *   // these two lines are equivalent, but the second approach is recommended
1035      *   dateTime = thisDuration.subtractFrom(dateTime);
1036      *   dateTime = dateTime.minus(thisDuration);
1037      * </pre>
1038      * <p>
1039      * The calculation will subtract the seconds, then nanos.
1040      * Only non-zero amounts will be added.
1041      * <p>
1042      * This instance is immutable and unaffected by this method call.
1043      *
1044      * @param temporal  the temporal object to adjust, not null
1045      * @return an object of the same type with the adjustment made, not null
1046      * @throws DateTimeException if unable to subtract
1047      * @throws ArithmeticException if numeric overflow occurs
1048      */
1049     @Override
1050     public Temporal subtractFrom(Temporal temporal) {
1051         if (seconds != 0) {
1052             temporal = temporal.minus(seconds, SECONDS);
1053         }
1054         if (nanos != 0) {
1055             temporal = temporal.minus(nanos, NANOS);
1056         }
1057         return temporal;
1058     }
1059 
1060     //-----------------------------------------------------------------------
1061     /**
1062      * Gets the number of minutes in this duration.
1063      * <p>
1064      * This returns the total number of minutes in the duration by dividing the
1065      * number of seconds by 86400.
1066      * This is based on the standard definition of a day as 24 hours.
1067      * <p>
1068      * This instance is immutable and unaffected by this method call.
1069      *
1070      * @return the number of minutes in the duration, may be negative
1071      */
1072     public long toDays() {
1073         return seconds / SECONDS_PER_DAY;
1074     }
1075 
1076     /**
1077      * Gets the number of minutes in this duration.
1078      * <p>
1079      * This returns the total number of minutes in the duration by dividing the
1080      * number of seconds by 3600.
1081      * <p>
1082      * This instance is immutable and unaffected by this method call.
1083      *
1084      * @return the number of minutes in the duration, may be negative
1085      */
1086     public long toHours() {
1087         return seconds / SECONDS_PER_HOUR;
1088     }
1089 
1090     /**
1091      * Gets the number of minutes in this duration.
1092      * <p>
1093      * This returns the total number of minutes in the duration by dividing the
1094      * number of seconds by 60.
1095      * <p>
1096      * This instance is immutable and unaffected by this method call.
1097      *
1098      * @return the number of minutes in the duration, may be negative
1099      */
1100     public long toMinutes() {
1101         return seconds / SECONDS_PER_MINUTE;
1102     }
1103 
1104     /**
1105      * Converts this duration to the total length in milliseconds.
1106      * <p>
1107      * If this duration is too large to fit in a {@code long} milliseconds, then an
1108      * exception is thrown.
1109      * <p>
1110      * If this duration has greater than millisecond precision, then the conversion
1111      * will drop any excess precision information as though the amount in nanoseconds
1112      * was subject to integer division by one million.
1113      *
1114      * @return the total length of the duration in milliseconds
1115      * @throws ArithmeticException if numeric overflow occurs
1116      */
1117     public long toMillis() {
1118         long millis = Math.multiplyExact(seconds, 1000);
1119         millis = Math.addExact(millis, nanos / 1000_000);
1120         return millis;
1121     }
1122 
1123     /**
1124      * Converts this duration to the total length in nanoseconds expressed as a {@code long}.
1125      * <p>
1126      * If this duration is too large to fit in a {@code long} nanoseconds, then an
1127      * exception is thrown.
1128      *
1129      * @return the total length of the duration in nanoseconds
1130      * @throws ArithmeticException if numeric overflow occurs
1131      */
1132     public long toNanos() {
1133         long millis = Math.multiplyExact(seconds, NANOS_PER_SECOND);
1134         millis = Math.addExact(millis, nanos);
1135         return millis;
1136     }
1137 
1138     //-----------------------------------------------------------------------
1139     /**
1140      * Compares this duration to the specified {@code Duration}.
1141      * <p>
1142      * The comparison is based on the total length of the durations.
1143      * It is "consistent with equals", as defined by {@link Comparable}.
1144      *
1145      * @param otherDuration  the other duration to compare to, not null
1146      * @return the comparator value, negative if less, positive if greater
1147      */
1148     @Override
1149     public int compareTo(Duration otherDuration) {
1150         int cmp = Long.compare(seconds, otherDuration.seconds);
1151         if (cmp != 0) {
1152             return cmp;
1153         }
1154         return nanos - otherDuration.nanos;
1155     }
1156 
























1157     //-----------------------------------------------------------------------
1158     /**
1159      * Checks if this duration is equal to the specified {@code Duration}.
1160      * <p>
1161      * The comparison is based on the total length of the durations.
1162      *
1163      * @param otherDuration  the other duration, null returns false
1164      * @return true if the other duration is equal to this one
1165      */
1166     @Override
1167     public boolean equals(Object otherDuration) {
1168         if (this == otherDuration) {
1169             return true;
1170         }
1171         if (otherDuration instanceof Duration) {
1172             Duration other = (Duration) otherDuration;
1173             return this.seconds == other.seconds &&
1174                    this.nanos == other.nanos;
1175         }
1176         return false;
1177     }
1178 
1179     /**
1180      * A hash code for this duration.
1181      *
1182      * @return a suitable hash code
1183      */
1184     @Override
1185     public int hashCode() {
1186         return ((int) (seconds ^ (seconds >>> 32))) + (51 * nanos);
1187     }
1188 
1189     //-----------------------------------------------------------------------
1190     /**
1191      * A string representation of this duration using ISO-8601 seconds
1192      * based representation, such as {@code PT8H6M12.345S}.
1193      * <p>
1194      * The format of the returned string will be {@code PTnHnMnS}, where n is
1195      * the relevant hours, minutes or seconds part of the duration.
1196      * Any fractional seconds are placed after a decimal point i the seconds section.
1197      * If a section has a zero value, it is omitted.
1198      * The hours, minutes and seconds will all have the same sign.
1199      * <p>
1200      * Examples:
1201      * <pre>
1202      *    "20.345 seconds"                 -> "PT20.345S
1203      *    "15 minutes" (15 * 60 seconds)   -> "PT15M"
1204      *    "10 hours" (10 * 3600 seconds)   -> "PT10H"
1205      *    "2 days" (2 * 86400 seconds)     -> "PT48H"
1206      * </pre>
1207      * Note that multiples of 24 hours are not output as days to avoid confusion
1208      * with {@code Period}.
1209      *
1210      * @return an ISO-8601 representation of this duration, not null
1211      */
1212     @Override
1213     public String toString() {
1214         if (this == ZERO) {
1215             return "PT0S";
1216         }
1217         long hours = seconds / SECONDS_PER_HOUR;
1218         int minutes = (int) ((seconds % SECONDS_PER_HOUR) / SECONDS_PER_MINUTE);
1219         int secs = (int) (seconds % SECONDS_PER_MINUTE);
1220         StringBuilder buf = new StringBuilder(24);
1221         buf.append("PT");
1222         if (hours != 0) {
1223             buf.append(hours).append('H');
1224         }
1225         if (minutes != 0) {
1226             buf.append(minutes).append('M');
1227         }
1228         if (secs == 0 && nanos == 0 && buf.length() > 2) {
1229             return buf.toString();
1230         }
1231         if (secs < 0 && nanos > 0) {
1232             if (secs == -1) {
1233                 buf.append("-0");
1234             } else {
1235                 buf.append(secs + 1);
1236             }
1237         } else {
1238             buf.append(secs);
1239         }
1240         if (nanos > 0) {
1241             int pos = buf.length();
1242             if (secs < 0) {
1243                 buf.append(2 * NANOS_PER_SECOND - nanos);
1244             } else {
1245                 buf.append(nanos + NANOS_PER_SECOND);
1246             }
1247             while (buf.charAt(buf.length() - 1) == '0') {
1248                 buf.setLength(buf.length() - 1);
1249             }
1250             buf.setCharAt(pos, '.');
1251         }
1252         buf.append('S');
1253         return buf.toString();
1254     }
1255 
1256     //-----------------------------------------------------------------------
1257     /**
1258      * Writes the object using a
1259      * <a href="../../serialized-form.html#java.time.Ser">dedicated serialized form</a>.
1260      * <pre>
1261      *  out.writeByte(1);  // identifies this as a Duration
1262      *  out.writeLong(seconds);