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/*
 * 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/
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package java.util.concurrent;

/**
 * A 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
 * 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.
 *
 * 

A 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: * *

  Lock lock = ...;
 *  if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ...
 * 
* while this code will timeout in 50 seconds: *
 *  Lock lock = ...;
 *  if (lock.tryLock(50L, TimeUnit.SECONDS)) ...
 * 
* * 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 TimeUnit. * * @since 1.5 * @author Doug Lea */ public enum TimeUnit { 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)); } }, 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)); } }, 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; } }, 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; } }, 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; } }, 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; } }, 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. /** * Convert the given time duration in the given unit to this * unit. Conversions from finer to coarser granularities * truncate, so lose precision. For example converting * 999 milliseconds to seconds results in * 0. Conversions from coarser to finer granularities * with arguments that would numerically overflow saturate to * Long.MIN_VALUE if negative or Long.MAX_VALUE * if positive. * *

For example, to convert 10 minutes to milliseconds, use: * TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES) * * @param sourceDuration the time duration in the given sourceUnit * @param sourceUnit the unit of the sourceDuration argument * @return the converted duration in this unit, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. */ public long convert(long sourceDuration, TimeUnit sourceUnit) { throw new AbstractMethodError(); } /** * Equivalent to NANOSECONDS.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert */ public long toNanos(long duration) { throw new AbstractMethodError(); } /** * Equivalent to MICROSECONDS.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert */ public long toMicros(long duration) { throw new AbstractMethodError(); } /** * Equivalent to MILLISECONDS.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert */ public long toMillis(long duration) { throw new AbstractMethodError(); } /** * Equivalent to SECONDS.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert */ public long toSeconds(long duration) { throw new AbstractMethodError(); } /** * Equivalent to MINUTES.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert * @since 1.6 */ public long toMinutes(long duration) { throw new AbstractMethodError(); } /** * Equivalent to HOURS.convert(duration, this). * @param duration the duration * @return the converted duration, * or Long.MIN_VALUE if conversion would negatively * overflow, or Long.MAX_VALUE if it would positively overflow. * @see #convert * @since 1.6 */ public long toHours(long duration) { throw new AbstractMethodError(); } /** * Equivalent to DAYS.convert(duration, this). * @param duration the duration * @return the converted duration * @see #convert * @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 Object.wait method. * *

For example, you could implement a blocking poll * method (see {@link BlockingQueue#poll BlockingQueue.poll}) * using: * *

 {@code
	 * public synchronized Object poll(long timeout, TimeUnit unit)
	 *     throws InterruptedException {
	 *   while (empty) {
	 *     unit.timedWait(this, timeout);
	 *     ...
	 *   }
	 * }}
* * @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 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 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); } } }




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