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	/*
	* 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;

	/**
	* 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)((dC1) - (mC2)); }
	},

	/**
	* 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
	*/
	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
	*/
	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
	*/
	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);
	}
	}

	}

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