util/concurrent/TimeUnit.java

/*
 * 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.time.Duration;
import java.time.temporal.ChronoUnit;
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(TimeUnit.NANO_SCALE),
    /**
     * Time unit representing one thousandth of a millisecond.
     */
    MICROSECONDS(TimeUnit.MICRO_SCALE),
    /**
     * Time unit representing one thousandth of a second.
     */
    MILLISECONDS(TimeUnit.MILLI_SCALE),
    /**
     * Time unit representing one second.
     */
    SECONDS(TimeUnit.SECOND_SCALE),
    /**
     * Time unit representing sixty seconds.
     * @since 1.6
     */
    MINUTES(TimeUnit.MINUTE_SCALE),
    /**
     * Time unit representing sixty minutes.
     * @since 1.6
     */
    HOURS(TimeUnit.HOUR_SCALE),
    /**
     * Time unit representing twenty four hours.
     * @since 1.6
     */
    DAYS(TimeUnit.DAY_SCALE);

    // Scales as constants
    private static final long NANO_SCALE   = 1L;
    private static final long MICRO_SCALE  = 1000L * NANO_SCALE;
    private static final long MILLI_SCALE  = 1000L * MICRO_SCALE;
    private static final long SECOND_SCALE = 1000L * MILLI_SCALE;
    private static final long MINUTE_SCALE = 60L * SECOND_SCALE;
    private static final long HOUR_SCALE   = 60L * MINUTE_SCALE;
    private static final long DAY_SCALE    = 24L * HOUR_SCALE;

    /*
     * Instances cache conversion ratios and saturation cutoffs for
     * the units up through SECONDS. Other cases compute them, in
     * method cvt.
     */

    private final long scale;
    private final long maxNanos;
    private final long maxMicros;
    private final long maxMillis;
    private final long maxSecs;
    private final long microRatio;
    private final int milliRatio;   // fits in 32 bits
    private final int secRatio;     // fits in 32 bits

    private TimeUnit(long s) {
        this.scale = s;
        this.maxNanos = Long.MAX_VALUE / s;
        long ur = (s >= MICRO_SCALE) ? (s / MICRO_SCALE) : (MICRO_SCALE / s);
        this.microRatio = ur;
        this.maxMicros = Long.MAX_VALUE / ur;
        long mr = (s >= MILLI_SCALE) ? (s / MILLI_SCALE) : (MILLI_SCALE / s);
        this.milliRatio = (int)mr;
        this.maxMillis = Long.MAX_VALUE / mr;
        long sr = (s >= SECOND_SCALE) ? (s / SECOND_SCALE) : (SECOND_SCALE / s);
        this.secRatio = (int)sr;
        this.maxSecs = Long.MAX_VALUE / sr;
    }

    /**
     * General conversion utility.
     *
     * @param d duration
     * @param dst result unit scale
     * @param src source unit scale
     */
    private static long cvt(long d, long dst, long src) {
        long r, m;
        if (src == dst)
            return d;
        else if (src < dst)
            return d / (dst / src);
        else if (d > (m = Long.MAX_VALUE / (r = src / dst)))
            return Long.MAX_VALUE;
        else if (d < -m)
            return Long.MIN_VALUE;
        else
            return d * r;
    }

    /**
     * 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) {
        switch (this) {
        case NANOSECONDS:  return sourceUnit.toNanos(sourceDuration);
        case MICROSECONDS: return sourceUnit.toMicros(sourceDuration);
        case MILLISECONDS: return sourceUnit.toMillis(sourceDuration);
        case SECONDS:      return sourceUnit.toSeconds(sourceDuration);
        default: return cvt(sourceDuration, scale, sourceUnit.scale);
        }
    }

    /**
     * Converts the given time duration to this unit.
     *
     * <p>For any TimeUnit {@code unit},
     * {@code unit.convert(Duration.ofNanos(n))}
     * is equivalent to
     * {@code unit.convert(n, NANOSECONDS)}, and
     * {@code unit.convert(Duration.of(n, unit.toChronoUnit()))}
     * is equivalent to {@code n} (in the absence of overflow).
     *
     * @param duration the time duration
     * @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.
     * @throws NullPointerException if {@code duration} is null
     * @see Duration#of(long,TemporalUnit)
     * @since 11
     */
    public long convert(Duration duration) {
        long secs = duration.getSeconds();
        int nano = duration.getNano();
        if (secs < 0 && nano > 0) {
            // use representation compatible with integer division
            secs++;
            nano -= SECOND_SCALE;
        }
        final long s, nanoVal;
        // Optimize for the common case - NANOSECONDS without overflow
        if (this == NANOSECONDS)
            nanoVal = nano;
        else if ((s = scale) < SECOND_SCALE)
            nanoVal = nano / s;
        else if (this == SECONDS)
            return secs;
        else
            return secs / secRatio;
        long val = secs * secRatio + nanoVal;
        return ((secs < maxSecs && secs > -maxSecs) ||
                (secs == maxSecs && val > 0) ||
                (secs == -maxSecs && val < 0))
            ? val
            : (secs > 0) ? Long.MAX_VALUE : Long.MIN_VALUE;
    }

    /**
     * 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) {
        long s, m;
        if ((s = scale) == NANO_SCALE)
            return duration;
        else if (duration > (m = maxNanos))
            return Long.MAX_VALUE;
        else if (duration < -m)
            return Long.MIN_VALUE;
        else
            return duration * s;
    }

    /**
     * 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) {
        long s, m;
        if ((s = scale) <= MICRO_SCALE)
            return (s == MICRO_SCALE) ? duration : duration / microRatio;
        else if (duration > (m = maxMicros))
            return Long.MAX_VALUE;
        else if (duration < -m)
            return Long.MIN_VALUE;
        else
            return duration * microRatio;
    }

    /**
     * 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) {
        long s, m;
        if ((s = scale) <= MILLI_SCALE)
            return (s == MILLI_SCALE) ? duration : duration / milliRatio;
        else if (duration > (m = maxMillis))
            return Long.MAX_VALUE;
        else if (duration < -m)
            return Long.MIN_VALUE;
        else
            return duration * milliRatio;
    }

    /**
     * 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) {
        long s, m;
        if ((s = scale) <= SECOND_SCALE)
            return (s == SECOND_SCALE) ? duration : duration / secRatio;
        else if (duration > (m = maxSecs))
            return Long.MAX_VALUE;
        else if (duration < -m)
            return Long.MIN_VALUE;
        else
            return duration * secRatio;
    }

    /**
     * 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) {
        return cvt(duration, MINUTE_SCALE, scale);
    }

    /**
     * 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) {
        return cvt(duration, HOUR_SCALE, scale);
    }

    /**
     * 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) {
        return cvt(duration, DAY_SCALE, scale);
    }

    /**
     * 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
     */
    private int excessNanos(long d, long m) {
        long s;
        if ((s = scale) == NANO_SCALE)
            return (int)(d - (m * MILLI_SCALE));
        else if (s == MICRO_SCALE)
            return (int)((d * 1000L) - (m * MILLI_SCALE));
        else
            return 0;
    }

    /**
     * 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(long, TimeUnit) BlockingQueue.poll})
     * using:
     *
     * <pre> {@code
     * public E poll(long timeout, TimeUnit unit)
     *     throws InterruptedException {
     *   synchronized (lock) {
     *     while (isEmpty()) {
     *       unit.timedWait(lock, 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);
        }
    }

    /**
     * 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);
        }
    }

}
Revision:	1.5
Committed:	Fri Jun 8 02:20:22 2018 UTC (5 years, 11 months ago) by jsr166
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.4:	+59 -18 lines
Log Message:	sync from src/main
#	User	Rev	Content
1	jsr166	1.1	/*
2			* Written by Doug Lea with assistance from members of JCP JSR-166
3			* Expert Group and released to the public domain, as explained at
4			* http://creativecommons.org/publicdomain/zero/1.0/
5			*/
6
7			package java.util.concurrent;
8
9	jsr166	1.5	import java.time.Duration;
10	jsr166	1.1	import java.time.temporal.ChronoUnit;
11			import java.util.Objects;
12
13			/**
14			* A {@code TimeUnit} represents time durations at a given unit of
15			* granularity and provides utility methods to convert across units,
16			* and to perform timing and delay operations in these units. A
17			* {@code TimeUnit} does not maintain time information, but only
18			* helps organize and use time representations that may be maintained
19			* separately across various contexts. A nanosecond is defined as one
20			* thousandth of a microsecond, a microsecond as one thousandth of a
21			* millisecond, a millisecond as one thousandth of a second, a minute
22			* as sixty seconds, an hour as sixty minutes, and a day as twenty four
23			* hours.
24			*
25			* <p>A {@code TimeUnit} is mainly used to inform time-based methods
26			* how a given timing parameter should be interpreted. For example,
27			* the following code will timeout in 50 milliseconds if the {@link
28			* java.util.concurrent.locks.Lock lock} is not available:
29			*
30			* <pre> {@code
31			* Lock lock = ...;
32			* if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ...}</pre>
33			*
34			* while this code will timeout in 50 seconds:
35			* <pre> {@code
36			* Lock lock = ...;
37			* if (lock.tryLock(50L, TimeUnit.SECONDS)) ...}</pre>
38			*
39			* Note however, that there is no guarantee that a particular timeout
40			* implementation will be able to notice the passage of time at the
41			* same granularity as the given {@code TimeUnit}.
42			*
43			* @since 1.5
44			* @author Doug Lea
45			*/
46			public enum TimeUnit {
47			/**
48			* Time unit representing one thousandth of a microsecond.
49			*/
50	jsr166	1.3	NANOSECONDS(TimeUnit.NANO_SCALE),
51	jsr166	1.1	/**
52			* Time unit representing one thousandth of a millisecond.
53			*/
54	jsr166	1.3	MICROSECONDS(TimeUnit.MICRO_SCALE),
55	jsr166	1.1	/**
56			* Time unit representing one thousandth of a second.
57			*/
58	jsr166	1.3	MILLISECONDS(TimeUnit.MILLI_SCALE),
59	jsr166	1.1	/**
60			* Time unit representing one second.
61			*/
62	jsr166	1.3	SECONDS(TimeUnit.SECOND_SCALE),
63	jsr166	1.1	/**
64			* Time unit representing sixty seconds.
65			* @since 1.6
66			*/
67	jsr166	1.3	MINUTES(TimeUnit.MINUTE_SCALE),
68	jsr166	1.1	/**
69			* Time unit representing sixty minutes.
70			* @since 1.6
71			*/
72	jsr166	1.3	HOURS(TimeUnit.HOUR_SCALE),
73	jsr166	1.1	/**
74			* Time unit representing twenty four hours.
75			* @since 1.6
76			*/
77	jsr166	1.3	DAYS(TimeUnit.DAY_SCALE);
78	jsr166	1.1
79			// Scales as constants
80			private static final long NANO_SCALE = 1L;
81			private static final long MICRO_SCALE = 1000L * NANO_SCALE;
82			private static final long MILLI_SCALE = 1000L * MICRO_SCALE;
83			private static final long SECOND_SCALE = 1000L * MILLI_SCALE;
84			private static final long MINUTE_SCALE = 60L * SECOND_SCALE;
85			private static final long HOUR_SCALE = 60L * MINUTE_SCALE;
86			private static final long DAY_SCALE = 24L * HOUR_SCALE;
87
88			/*
89			* Instances cache conversion ratios and saturation cutoffs for
90	dl	1.2	* the units up through SECONDS. Other cases compute them, in
91	jsr166	1.1	* method cvt.
92			*/
93
94			private final long scale;
95			private final long maxNanos;
96	dl	1.2	private final long maxMicros;
97	jsr166	1.1	private final long maxMillis;
98			private final long maxSecs;
99	dl	1.2	private final long microRatio;
100			private final int milliRatio; // fits in 32 bits
101			private final int secRatio; // fits in 32 bits
102
103	jsr166	1.4	private TimeUnit(long s) {
104	dl	1.2	this.scale = s;
105			this.maxNanos = Long.MAX_VALUE / s;
106			long ur = (s >= MICRO_SCALE) ? (s / MICRO_SCALE) : (MICRO_SCALE / s);
107			this.microRatio = ur;
108			this.maxMicros = Long.MAX_VALUE / ur;
109	jsr166	1.3	long mr = (s >= MILLI_SCALE) ? (s / MILLI_SCALE) : (MILLI_SCALE / s);
110	jsr166	1.1	this.milliRatio = (int)mr;
111			this.maxMillis = Long.MAX_VALUE / mr;
112	dl	1.2	long sr = (s >= SECOND_SCALE) ? (s / SECOND_SCALE) : (SECOND_SCALE / s);
113	jsr166	1.1	this.secRatio = (int)sr;
114			this.maxSecs = Long.MAX_VALUE / sr;
115			}
116
117			/**
118			* General conversion utility.
119			*
120			* @param d duration
121	jsr166	1.3	* @param dst result unit scale
122			* @param src source unit scale
123	jsr166	1.1	*/
124			private static long cvt(long d, long dst, long src) {
125			long r, m;
126			if (src == dst)
127			return d;
128			else if (src < dst)
129			return d / (dst / src);
130			else if (d > (m = Long.MAX_VALUE / (r = src / dst)))
131			return Long.MAX_VALUE;
132			else if (d < -m)
133			return Long.MIN_VALUE;
134			else
135			return d * r;
136			}
137
138			/**
139			* Converts the given time duration in the given unit to this unit.
140			* Conversions from finer to coarser granularities truncate, so
141			* lose precision. For example, converting {@code 999} milliseconds
142			* to seconds results in {@code 0}. Conversions from coarser to
143			* finer granularities with arguments that would numerically
144			* overflow saturate to {@code Long.MIN_VALUE} if negative or
145			* {@code Long.MAX_VALUE} if positive.
146			*
147			* <p>For example, to convert 10 minutes to milliseconds, use:
148			* {@code TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)}
149			*
150			* @param sourceDuration the time duration in the given {@code sourceUnit}
151			* @param sourceUnit the unit of the {@code sourceDuration} argument
152			* @return the converted duration in this unit,
153	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
154			* or {@code Long.MAX_VALUE} if it would positively overflow.
155	jsr166	1.1	*/
156			public long convert(long sourceDuration, TimeUnit sourceUnit) {
157	dl	1.2	switch (this) {
158	jsr166	1.3	case NANOSECONDS: return sourceUnit.toNanos(sourceDuration);
159	dl	1.2	case MICROSECONDS: return sourceUnit.toMicros(sourceDuration);
160			case MILLISECONDS: return sourceUnit.toMillis(sourceDuration);
161	jsr166	1.3	case SECONDS: return sourceUnit.toSeconds(sourceDuration);
162	dl	1.2	default: return cvt(sourceDuration, scale, sourceUnit.scale);
163			}
164	jsr166	1.1	}
165
166			/**
167	jsr166	1.5	* Converts the given time duration to this unit.
168			*
169			* <p>For any TimeUnit {@code unit},
170			* {@code unit.convert(Duration.ofNanos(n))}
171			* is equivalent to
172			* {@code unit.convert(n, NANOSECONDS)}, and
173			* {@code unit.convert(Duration.of(n, unit.toChronoUnit()))}
174			* is equivalent to {@code n} (in the absence of overflow).
175			*
176			* @param duration the time duration
177			* @return the converted duration in this unit,
178			* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
179			* or {@code Long.MAX_VALUE} if it would positively overflow.
180			* @throws NullPointerException if {@code duration} is null
181			* @see Duration#of(long,TemporalUnit)
182			* @since 11
183			*/
184			public long convert(Duration duration) {
185			long secs = duration.getSeconds();
186			int nano = duration.getNano();
187			if (secs < 0 && nano > 0) {
188			// use representation compatible with integer division
189			secs++;
190			nano -= SECOND_SCALE;
191			}
192			final long s, nanoVal;
193			// Optimize for the common case - NANOSECONDS without overflow
194			if (this == NANOSECONDS)
195			nanoVal = nano;
196			else if ((s = scale) < SECOND_SCALE)
197			nanoVal = nano / s;
198			else if (this == SECONDS)
199			return secs;
200			else
201			return secs / secRatio;
202			long val = secs * secRatio + nanoVal;
203			return ((secs < maxSecs && secs > -maxSecs) \|\|
204			(secs == maxSecs && val > 0) \|\|
205			(secs == -maxSecs && val < 0))
206			? val
207			: (secs > 0) ? Long.MAX_VALUE : Long.MIN_VALUE;
208			}
209
210			/**
211	jsr166	1.1	* Equivalent to
212			* {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
213			* @param duration the duration
214			* @return the converted duration,
215	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
216			* or {@code Long.MAX_VALUE} if it would positively overflow.
217	jsr166	1.1	*/
218			public long toNanos(long duration) {
219			long s, m;
220			if ((s = scale) == NANO_SCALE)
221			return duration;
222			else if (duration > (m = maxNanos))
223			return Long.MAX_VALUE;
224			else if (duration < -m)
225			return Long.MIN_VALUE;
226			else
227			return duration * s;
228			}
229
230			/**
231			* Equivalent to
232			* {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
233			* @param duration the duration
234			* @return the converted duration,
235	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
236			* or {@code Long.MAX_VALUE} if it would positively overflow.
237	jsr166	1.1	*/
238			public long toMicros(long duration) {
239	dl	1.2	long s, m;
240	jsr166	1.5	if ((s = scale) <= MICRO_SCALE)
241			return (s == MICRO_SCALE) ? duration : duration / microRatio;
242	dl	1.2	else if (duration > (m = maxMicros))
243			return Long.MAX_VALUE;
244			else if (duration < -m)
245			return Long.MIN_VALUE;
246			else
247			return duration * microRatio;
248	jsr166	1.1	}
249
250			/**
251			* Equivalent to
252			* {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
253			* @param duration the duration
254			* @return the converted duration,
255	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
256			* or {@code Long.MAX_VALUE} if it would positively overflow.
257	jsr166	1.1	*/
258			public long toMillis(long duration) {
259			long s, m;
260	jsr166	1.5	if ((s = scale) <= MILLI_SCALE)
261			return (s == MILLI_SCALE) ? duration : duration / milliRatio;
262	jsr166	1.1	else if (duration > (m = maxMillis))
263			return Long.MAX_VALUE;
264			else if (duration < -m)
265			return Long.MIN_VALUE;
266			else
267			return duration * milliRatio;
268			}
269
270			/**
271			* Equivalent to
272			* {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
273			* @param duration the duration
274			* @return the converted duration,
275	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
276			* or {@code Long.MAX_VALUE} if it would positively overflow.
277	jsr166	1.1	*/
278			public long toSeconds(long duration) {
279			long s, m;
280	jsr166	1.5	if ((s = scale) <= SECOND_SCALE)
281			return (s == SECOND_SCALE) ? duration : duration / secRatio;
282	jsr166	1.1	else if (duration > (m = maxSecs))
283			return Long.MAX_VALUE;
284			else if (duration < -m)
285			return Long.MIN_VALUE;
286			else
287			return duration * secRatio;
288			}
289
290			/**
291			* Equivalent to
292			* {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
293			* @param duration the duration
294			* @return the converted duration,
295	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
296			* or {@code Long.MAX_VALUE} if it would positively overflow.
297	jsr166	1.1	* @since 1.6
298			*/
299			public long toMinutes(long duration) {
300			return cvt(duration, MINUTE_SCALE, scale);
301			}
302
303			/**
304			* Equivalent to
305			* {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
306			* @param duration the duration
307			* @return the converted duration,
308	jsr166	1.3	* or {@code Long.MIN_VALUE} if conversion would negatively overflow,
309			* or {@code Long.MAX_VALUE} if it would positively overflow.
310	jsr166	1.1	* @since 1.6
311			*/
312			public long toHours(long duration) {
313			return cvt(duration, HOUR_SCALE, scale);
314			}
315
316			/**
317			* Equivalent to
318			* {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
319			* @param duration the duration
320			* @return the converted duration
321			* @since 1.6
322			*/
323			public long toDays(long duration) {
324			return cvt(duration, DAY_SCALE, scale);
325			}
326
327			/**
328			* Utility to compute the excess-nanosecond argument to wait,
329			* sleep, join.
330			* @param d the duration
331			* @param m the number of milliseconds
332			* @return the number of nanoseconds
333			*/
334			private int excessNanos(long d, long m) {
335			long s;
336			if ((s = scale) == NANO_SCALE)
337			return (int)(d - (m * MILLI_SCALE));
338			else if (s == MICRO_SCALE)
339			return (int)((d * 1000L) - (m * MILLI_SCALE));
340			else
341			return 0;
342			}
343
344			/**
345			* Performs a timed {@link Object#wait(long, int) Object.wait}
346			* using this time unit.
347			* This is a convenience method that converts timeout arguments
348			* into the form required by the {@code Object.wait} method.
349			*
350	jsr166	1.5	* <p>For example, you could implement a blocking {@code poll} method
351			* (see {@link BlockingQueue#poll(long, TimeUnit) BlockingQueue.poll})
352	jsr166	1.1	* using:
353			*
354			* <pre> {@code
355	jsr166	1.5	* public E poll(long timeout, TimeUnit unit)
356	jsr166	1.1	* throws InterruptedException {
357	jsr166	1.5	* synchronized (lock) {
358			* while (isEmpty()) {
359			* unit.timedWait(lock, timeout);
360			* ...
361			* }
362	jsr166	1.1	* }
363			* }}</pre>
364			*
365			* @param obj the object to wait on
366			* @param timeout the maximum time to wait. If less than
367			* or equal to zero, do not wait at all.
368			* @throws InterruptedException if interrupted while waiting
369			*/
370			public void timedWait(Object obj, long timeout)
371			throws InterruptedException {
372			if (timeout > 0) {
373			long ms = toMillis(timeout);
374			int ns = excessNanos(timeout, ms);
375			obj.wait(ms, ns);
376			}
377			}
378
379			/**
380			* Performs a timed {@link Thread#join(long, int) Thread.join}
381			* using this time unit.
382			* This is a convenience method that converts time arguments into the
383			* form required by the {@code Thread.join} method.
384			*
385			* @param thread the thread to wait for
386			* @param timeout the maximum time to wait. If less than
387			* or equal to zero, do not wait at all.
388			* @throws InterruptedException if interrupted while waiting
389			*/
390			public void timedJoin(Thread thread, long timeout)
391			throws InterruptedException {
392			if (timeout > 0) {
393			long ms = toMillis(timeout);
394			int ns = excessNanos(timeout, ms);
395			thread.join(ms, ns);
396			}
397			}
398
399			/**
400			* Performs a {@link Thread#sleep(long, int) Thread.sleep} using
401			* this time unit.
402			* This is a convenience method that converts time arguments into the
403			* form required by the {@code Thread.sleep} method.
404			*
405			* @param timeout the minimum time to sleep. If less than
406			* or equal to zero, do not sleep at all.
407			* @throws InterruptedException if interrupted while sleeping
408			*/
409			public void sleep(long timeout) throws InterruptedException {
410			if (timeout > 0) {
411			long ms = toMillis(timeout);
412			int ns = excessNanos(timeout, ms);
413			Thread.sleep(ms, ns);
414			}
415			}
416
417			/**
418			* Converts this {@code TimeUnit} to the equivalent {@code ChronoUnit}.
419			*
420			* @return the converted equivalent ChronoUnit
421			* @since 9
422			*/
423			public ChronoUnit toChronoUnit() {
424			switch (this) {
425			case NANOSECONDS: return ChronoUnit.NANOS;
426			case MICROSECONDS: return ChronoUnit.MICROS;
427			case MILLISECONDS: return ChronoUnit.MILLIS;
428			case SECONDS: return ChronoUnit.SECONDS;
429			case MINUTES: return ChronoUnit.MINUTES;
430			case HOURS: return ChronoUnit.HOURS;
431			case DAYS: return ChronoUnit.DAYS;
432			default: throw new AssertionError();
433			}
434			}
435
436			/**
437			* Converts a {@code ChronoUnit} to the equivalent {@code TimeUnit}.
438			*
439			* @param chronoUnit the ChronoUnit to convert
440			* @return the converted equivalent TimeUnit
441			* @throws IllegalArgumentException if {@code chronoUnit} has no
442			* equivalent TimeUnit
443			* @throws NullPointerException if {@code chronoUnit} is null
444			* @since 9
445			*/
446			public static TimeUnit of(ChronoUnit chronoUnit) {
447			switch (Objects.requireNonNull(chronoUnit, "chronoUnit")) {
448			case NANOS: return TimeUnit.NANOSECONDS;
449			case MICROS: return TimeUnit.MICROSECONDS;
450			case MILLIS: return TimeUnit.MILLISECONDS;
451			case SECONDS: return TimeUnit.SECONDS;
452			case MINUTES: return TimeUnit.MINUTES;
453			case HOURS: return TimeUnit.HOURS;
454			case DAYS: return TimeUnit.DAYS;
455			default:
456			throw new IllegalArgumentException(
457			"No TimeUnit equivalent for " + chronoUnit);
458			}
459			}
460
461			}