content: /*
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  /*
   * This file is available under and governed by the GNU General Public
   * License version 2 only, as published by the Free Software Foundation.
   * However, the following notice accompanied the original version of this
   * file:
   *
   * Written by Doug Lea with assistance from members of JCP JSR-166
   * Expert Group and released to the public domain, as explained at
   * http://creativecommons.org/publicdomain/zero/1.0/
   */
  
  package java.util.concurrent;
  
  import java.util.Objects;
  
  /**
   * A {@code TimeUnit} represents time durations at a given unit of
   * granularity and provides utility methods to convert across units,
   * and to perform timing and delay operations in these units.  A
   * {@code TimeUnit} does not maintain time information, but only
   * helps organize and use time representations that may be maintained
   * separately across various contexts.  A nanosecond is defined as one
   * thousandth of a microsecond, a microsecond as one thousandth of a
   * millisecond, a millisecond as one thousandth of a second, a minute
   * as sixty seconds, an hour as sixty minutes, and a day as twenty four
   * hours.
   *
   * <p>A {@code TimeUnit} is mainly used to inform time-based methods
   * how a given timing parameter should be interpreted. For example,
   * the following code will timeout in 50 milliseconds if the {@link
   * java.util.concurrent.locks.Lock lock} is not available:
   *
   * <pre> {@code
   * Lock lock = ...;
   * if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ...}</pre>
   *
   * while this code will timeout in 50 seconds:
   * <pre> {@code
   * Lock lock = ...;
   * if (lock.tryLock(50L, TimeUnit.SECONDS)) ...}</pre>
   *
   * Note however, that there is no guarantee that a particular timeout
   * implementation will be able to notice the passage of time at the
   * same granularity as the given {@code TimeUnit}.
   *
   * @since 1.5
   * @author Doug Lea
   */
  public enum TimeUnit {
      /**
       * Time unit representing one thousandth of a microsecond.
       */
      NANOSECONDS {
          public long toNanos(long d)   { return d; }
          public long toMicros(long d)  { return d/(C1/C0); }
          public long toMillis(long d)  { return d/(C2/C0); }
          public long toSeconds(long d) { return d/(C3/C0); }
          public long toMinutes(long d) { return d/(C4/C0); }
          public long toHours(long d)   { return d/(C5/C0); }
          public long toDays(long d)    { return d/(C6/C0); }
          public long convert(long d, TimeUnit u) { return u.toNanos(d); }
          int excessNanos(long d, long m) { return (int)(d - (m*C2)); }
      },
  
      /**
       * Time unit representing one thousandth of a millisecond.
       */
      MICROSECONDS {
          public long toNanos(long d)   { return x(d, C1/C0, MAX/(C1/C0)); }
          public long toMicros(long d)  { return d; }
          public long toMillis(long d)  { return d/(C2/C1); }
          public long toSeconds(long d) { return d/(C3/C1); }
          public long toMinutes(long d) { return d/(C4/C1); }
          public long toHours(long d)   { return d/(C5/C1); }
          public long toDays(long d)    { return d/(C6/C1); }
          public long convert(long d, TimeUnit u) { return u.toMicros(d); }
          int excessNanos(long d, long m) { return (int)((d*C1) - (m*C2)); }
      },
  
      /**
       * Time unit representing one thousandth of a second.
       */
      MILLISECONDS {
          public long toNanos(long d)   { return x(d, C2/C0, MAX/(C2/C0)); }
          public long toMicros(long d)  { return x(d, C2/C1, MAX/(C2/C1)); }
          public long toMillis(long d)  { return d; }
          public long toSeconds(long d) { return d/(C3/C2); }
          public long toMinutes(long d) { return d/(C4/C2); }
          public long toHours(long d)   { return d/(C5/C2); }
          public long toDays(long d)    { return d/(C6/C2); }
          public long convert(long d, TimeUnit u) { return u.toMillis(d); }
          int excessNanos(long d, long m) { return 0; }
      },
  
      /**
       * Time unit representing one second.
       */
      SECONDS {
          public long toNanos(long d)   { return x(d, C3/C0, MAX/(C3/C0)); }
          public long toMicros(long d)  { return x(d, C3/C1, MAX/(C3/C1)); }
          public long toMillis(long d)  { return x(d, C3/C2, MAX/(C3/C2)); }
          public long toSeconds(long d) { return d; }
          public long toMinutes(long d) { return d/(C4/C3); }
          public long toHours(long d)   { return d/(C5/C3); }
          public long toDays(long d)    { return d/(C6/C3); }
          public long convert(long d, TimeUnit u) { return u.toSeconds(d); }
          int excessNanos(long d, long m) { return 0; }
      },
  
      /**
       * Time unit representing sixty seconds.
       * @since 1.6
       */
      MINUTES {
          public long toNanos(long d)   { return x(d, C4/C0, MAX/(C4/C0)); }
          public long toMicros(long d)  { return x(d, C4/C1, MAX/(C4/C1)); }
          public long toMillis(long d)  { return x(d, C4/C2, MAX/(C4/C2)); }
          public long toSeconds(long d) { return x(d, C4/C3, MAX/(C4/C3)); }
          public long toMinutes(long d) { return d; }
          public long toHours(long d)   { return d/(C5/C4); }
          public long toDays(long d)    { return d/(C6/C4); }
          public long convert(long d, TimeUnit u) { return u.toMinutes(d); }
          int excessNanos(long d, long m) { return 0; }
      },
  
      /**
       * Time unit representing sixty minutes.
       * @since 1.6
       */
      HOURS {
          public long toNanos(long d)   { return x(d, C5/C0, MAX/(C5/C0)); }
          public long toMicros(long d)  { return x(d, C5/C1, MAX/(C5/C1)); }
          public long toMillis(long d)  { return x(d, C5/C2, MAX/(C5/C2)); }
          public long toSeconds(long d) { return x(d, C5/C3, MAX/(C5/C3)); }
          public long toMinutes(long d) { return x(d, C5/C4, MAX/(C5/C4)); }
          public long toHours(long d)   { return d; }
          public long toDays(long d)    { return d/(C6/C5); }
          public long convert(long d, TimeUnit u) { return u.toHours(d); }
          int excessNanos(long d, long m) { return 0; }
      },
  
      /**
       * Time unit representing twenty four hours.
       * @since 1.6
       */
      DAYS {
          public long toNanos(long d)   { return x(d, C6/C0, MAX/(C6/C0)); }
          public long toMicros(long d)  { return x(d, C6/C1, MAX/(C6/C1)); }
          public long toMillis(long d)  { return x(d, C6/C2, MAX/(C6/C2)); }
          public long toSeconds(long d) { return x(d, C6/C3, MAX/(C6/C3)); }
          public long toMinutes(long d) { return x(d, C6/C4, MAX/(C6/C4)); }
          public long toHours(long d)   { return x(d, C6/C5, MAX/(C6/C5)); }
          public long toDays(long d)    { return d; }
          public long convert(long d, TimeUnit u) { return u.toDays(d); }
          int excessNanos(long d, long m) { return 0; }
      };
  
      // Handy constants for conversion methods
      static final long C0 = 1L;
      static final long C1 = C0 * 1000L;
      static final long C2 = C1 * 1000L;
      static final long C3 = C2 * 1000L;
      static final long C4 = C3 * 60L;
      static final long C5 = C4 * 60L;
      static final long C6 = C5 * 24L;
  
      static final long MAX = Long.MAX_VALUE;
  
      /**
       * Scale d by m, checking for overflow.
       * This has a short name to make above code more readable.
       */
      static long x(long d, long m, long over) {
          if (d > +over) return Long.MAX_VALUE;
          if (d < -over) return Long.MIN_VALUE;
          return d * m;
      }
  
      // To maintain full signature compatibility with 1.5, and to improve the
      // clarity of the generated javadoc (see 6287639: Abstract methods in
      // enum classes should not be listed as abstract), method convert
      // etc. are not declared abstract but otherwise act as abstract methods.
  
      /**
       * Converts the given time duration in the given unit to this unit.
       * Conversions from finer to coarser granularities truncate, so
       * lose precision. For example, converting {@code 999} milliseconds
       * to seconds results in {@code 0}. Conversions from coarser to
       * finer granularities with arguments that would numerically
       * overflow saturate to {@code Long.MIN_VALUE} if negative or
       * {@code Long.MAX_VALUE} if positive.
       *
       * <p>For example, to convert 10 minutes to milliseconds, use:
       * {@code TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)}
       *
       * @param sourceDuration the time duration in the given {@code sourceUnit}
       * @param sourceUnit the unit of the {@code sourceDuration} argument
       * @return the converted duration in this unit,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       */
      public long convert(long sourceDuration, TimeUnit sourceUnit) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       */
      public long toNanos(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       */
      public long toMicros(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       */
      public long toMillis(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       */
      public long toSeconds(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       * @since 1.6
       */
      public long toMinutes(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration,
       * or {@code Long.MIN_VALUE} if conversion would negatively
       * overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
       * @since 1.6
       */
      public long toHours(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Equivalent to
       * {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
       * @param duration the duration
       * @return the converted duration
       * @since 1.6
       */
      public long toDays(long duration) {
          throw new AbstractMethodError();
      }
  
      /**
       * Utility to compute the excess-nanosecond argument to wait,
       * sleep, join.
       * @param d the duration
       * @param m the number of milliseconds
       * @return the number of nanoseconds
       */
      abstract int excessNanos(long d, long m);
  
      /**
       * Performs a timed {@link Object#wait(long, int) Object.wait}
       * using this time unit.
       * This is a convenience method that converts timeout arguments
       * into the form required by the {@code Object.wait} method.
       *
       * <p>For example, you could implement a blocking {@code poll}
       * method (see {@link BlockingQueue#poll BlockingQueue.poll})
       * using:
       *
       * <pre> {@code
       * public synchronized Object poll(long timeout, TimeUnit unit)
       *     throws InterruptedException {
       *   while (empty) {
       *     unit.timedWait(this, timeout);
       *     ...
       *   }
       * }}</pre>
       *
       * @param obj the object to wait on
       * @param timeout the maximum time to wait. If less than
       * or equal to zero, do not wait at all.
       * @throws InterruptedException if interrupted while waiting
       */
      public void timedWait(Object obj, long timeout)
              throws InterruptedException {
          if (timeout > 0) {
              long ms = toMillis(timeout);
              int ns = excessNanos(timeout, ms);
              obj.wait(ms, ns);
          }
      }
  
      /**
       * Performs a timed {@link Thread#join(long, int) Thread.join}
       * using this time unit.
       * This is a convenience method that converts time arguments into the
       * form required by the {@code Thread.join} method.
       *
       * @param thread the thread to wait for
       * @param timeout the maximum time to wait. If less than
       * or equal to zero, do not wait at all.
       * @throws InterruptedException if interrupted while waiting
       */
      public void timedJoin(Thread thread, long timeout)
              throws InterruptedException {
          if (timeout > 0) {
              long ms = toMillis(timeout);
              int ns = excessNanos(timeout, ms);
              thread.join(ms, ns);
          }
      }
  
      /**
       * Performs a {@link Thread#sleep(long, int) Thread.sleep} using
       * this time unit.
       * This is a convenience method that converts time arguments into the
       * form required by the {@code Thread.sleep} method.
       *
       * @param timeout the minimum time to sleep. If less than
       * or equal to zero, do not sleep at all.
       * @throws InterruptedException if interrupted while sleeping
       */
      public void sleep(long timeout) throws InterruptedException {
          if (timeout > 0) {
              long ms = toMillis(timeout);
              int ns = excessNanos(timeout, ms);
              Thread.sleep(ms, ns);
          }
      }
  
      // BEGIN Android-removed: OpenJDK 9 ChronoUnit related code.
      /*
      /**
       * Converts this {@code TimeUnit} to the equivalent {@code ChronoUnit}.
       *
       * @return the converted equivalent ChronoUnit
       * @since 9
       *
      public ChronoUnit toChronoUnit() {
          switch (this) {
          case NANOSECONDS:  return ChronoUnit.NANOS;
          case MICROSECONDS: return ChronoUnit.MICROS;
          case MILLISECONDS: return ChronoUnit.MILLIS;
          case SECONDS:      return ChronoUnit.SECONDS;
          case MINUTES:      return ChronoUnit.MINUTES;
          case HOURS:        return ChronoUnit.HOURS;
          case DAYS:         return ChronoUnit.DAYS;
          default: throw new AssertionError();
          }
      }
  
      /**
       * Converts a {@code ChronoUnit} to the equivalent {@code TimeUnit}.
       *
       * @param chronoUnit the ChronoUnit to convert
       * @return the converted equivalent TimeUnit
       * @throws IllegalArgumentException if {@code chronoUnit} has no
       *         equivalent TimeUnit
       * @throws NullPointerException if {@code chronoUnit} is null
       * @since 9
       *
      public static TimeUnit of(ChronoUnit chronoUnit) {
          switch (Objects.requireNonNull(chronoUnit, "chronoUnit")) {
          case NANOS:   return TimeUnit.NANOSECONDS;
          case MICROS:  return TimeUnit.MICROSECONDS;
          case MILLIS:  return TimeUnit.MILLISECONDS;
          case SECONDS: return TimeUnit.SECONDS;
          case MINUTES: return TimeUnit.MINUTES;
          case HOURS:   return TimeUnit.HOURS;
          case DAYS:    return TimeUnit.DAYS;
          default:
              throw new IllegalArgumentException(
                  "No TimeUnit equivalent for " + chronoUnit);
          }
      }
      */
      // END Android-removed: OpenJDK 9 ChronoUnit related code.
  
  }
  