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.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(1L), // (cannot use symbolic scale names here)
    /**
     * Time unit representing one thousandth of a millisecond.
     */
    MICROSECONDS(1000L),
    /**
     * Time unit representing one thousandth of a second.
     */
    MILLISECONDS(1000L * 1000L),
    /**
     * Time unit representing one second.
     */
    SECONDS(1000L * 1000L * 1000L),
    /**
     * Time unit representing sixty seconds.
     * @since 1.6
     */
    MINUTES(1000L * 1000L * 1000L * 60L),
    /**
     * Time unit representing sixty minutes.
     * @since 1.6
     */
    HOURS(1000L * 1000L * 1000L * 60L * 60L),
    /**
     * Time unit representing twenty four hours.
     * @since 1.6
     */
    DAYS(1000L * 1000L * 1000L * 60L * 60L * 24L);

    // 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

    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 = (scale >= 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 scale unit
     * @param src source scale unit
     */
    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);
        }
    }

    /**
     * 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 duration;
        else if (s < MICRO_SCALE)
            return 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 duration;
        else if (s < MILLI_SCALE)
            return 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 duration;
        else if (s < SECOND_SCALE)
            return 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 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);
        }
    }

    /**
     * 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:	1.2
Committed:	Sat Mar 26 12:02:03 2016 UTC (8 years, 2 months ago) by dl
Branch:	MAIN
Changes since 1.1:	+32 -16 lines
Log Message:	use jdk8 @Contended
#	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			import java.time.temporal.ChronoUnit;
10			import java.util.Objects;
11
12			/**
13			* A {@code TimeUnit} represents time durations at a given unit of
14			* granularity and provides utility methods to convert across units,
15			* and to perform timing and delay operations in these units. A
16			* {@code TimeUnit} does not maintain time information, but only
17			* helps organize and use time representations that may be maintained
18			* separately across various contexts. A nanosecond is defined as one
19			* thousandth of a microsecond, a microsecond as one thousandth of a
20			* millisecond, a millisecond as one thousandth of a second, a minute
21			* as sixty seconds, an hour as sixty minutes, and a day as twenty four
22			* hours.
23			*
24			* <p>A {@code TimeUnit} is mainly used to inform time-based methods
25			* how a given timing parameter should be interpreted. For example,
26			* the following code will timeout in 50 milliseconds if the {@link
27			* java.util.concurrent.locks.Lock lock} is not available:
28			*
29			* <pre> {@code
30			* Lock lock = ...;
31			* if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ...}</pre>
32			*
33			* while this code will timeout in 50 seconds:
34			* <pre> {@code
35			* Lock lock = ...;
36			* if (lock.tryLock(50L, TimeUnit.SECONDS)) ...}</pre>
37			*
38			* Note however, that there is no guarantee that a particular timeout
39			* implementation will be able to notice the passage of time at the
40			* same granularity as the given {@code TimeUnit}.
41			*
42			* @since 1.5
43			* @author Doug Lea
44			*/
45			public enum TimeUnit {
46			/**
47			* Time unit representing one thousandth of a microsecond.
48			*/
49			NANOSECONDS(1L), // (cannot use symbolic scale names here)
50			/**
51			* Time unit representing one thousandth of a millisecond.
52			*/
53			MICROSECONDS(1000L),
54			/**
55			* Time unit representing one thousandth of a second.
56			*/
57			MILLISECONDS(1000L * 1000L),
58			/**
59			* Time unit representing one second.
60			*/
61			SECONDS(1000L * 1000L * 1000L),
62			/**
63			* Time unit representing sixty seconds.
64			* @since 1.6
65			*/
66			MINUTES(1000L * 1000L * 1000L * 60L),
67			/**
68			* Time unit representing sixty minutes.
69			* @since 1.6
70			*/
71			HOURS(1000L * 1000L * 1000L * 60L * 60L),
72			/**
73			* Time unit representing twenty four hours.
74			* @since 1.6
75			*/
76			DAYS(1000L * 1000L * 1000L * 60L * 60L * 24L);
77
78			// Scales as constants
79			private static final long NANO_SCALE = 1L;
80			private static final long MICRO_SCALE = 1000L * NANO_SCALE;
81			private static final long MILLI_SCALE = 1000L * MICRO_SCALE;
82			private static final long SECOND_SCALE = 1000L * MILLI_SCALE;
83			private static final long MINUTE_SCALE = 60L * SECOND_SCALE;
84			private static final long HOUR_SCALE = 60L * MINUTE_SCALE;
85			private static final long DAY_SCALE = 24L * HOUR_SCALE;
86
87			/*
88			* Instances cache conversion ratios and saturation cutoffs for
89	dl	1.2	* the units up through SECONDS. Other cases compute them, in
90	jsr166	1.1	* method cvt.
91			*/
92
93			private final long scale;
94			private final long maxNanos;
95	dl	1.2	private final long maxMicros;
96	jsr166	1.1	private final long maxMillis;
97			private final long maxSecs;
98	dl	1.2	private final long microRatio;
99			private final int milliRatio; // fits in 32 bits
100			private final int secRatio; // fits in 32 bits
101
102			TimeUnit(long s) {
103			this.scale = s;
104			this.maxNanos = Long.MAX_VALUE / s;
105			long ur = (s >= MICRO_SCALE) ? (s / MICRO_SCALE) : (MICRO_SCALE / s);
106			this.microRatio = ur;
107			this.maxMicros = Long.MAX_VALUE / ur;
108			long mr = (scale >= MILLI_SCALE) ? (s / MILLI_SCALE) : (MILLI_SCALE / s);
109	jsr166	1.1	this.milliRatio = (int)mr;
110			this.maxMillis = Long.MAX_VALUE / mr;
111	dl	1.2	long sr = (s >= SECOND_SCALE) ? (s / SECOND_SCALE) : (SECOND_SCALE / s);
112	jsr166	1.1	this.secRatio = (int)sr;
113			this.maxSecs = Long.MAX_VALUE / sr;
114			}
115
116			/**
117			* General conversion utility.
118			*
119			* @param d duration
120			* @param dst result scale unit
121			* @param src source scale unit
122			*/
123			private static long cvt(long d, long dst, long src) {
124			long r, m;
125			if (src == dst)
126			return d;
127			else if (src < dst)
128			return d / (dst / src);
129			else if (d > (m = Long.MAX_VALUE / (r = src / dst)))
130			return Long.MAX_VALUE;
131			else if (d < -m)
132			return Long.MIN_VALUE;
133			else
134			return d * r;
135			}
136
137			/**
138			* Converts the given time duration in the given unit to this unit.
139			* Conversions from finer to coarser granularities truncate, so
140			* lose precision. For example, converting {@code 999} milliseconds
141			* to seconds results in {@code 0}. Conversions from coarser to
142			* finer granularities with arguments that would numerically
143			* overflow saturate to {@code Long.MIN_VALUE} if negative or
144			* {@code Long.MAX_VALUE} if positive.
145			*
146			* <p>For example, to convert 10 minutes to milliseconds, use:
147			* {@code TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)}
148			*
149			* @param sourceDuration the time duration in the given {@code sourceUnit}
150			* @param sourceUnit the unit of the {@code sourceDuration} argument
151			* @return the converted duration in this unit,
152			* or {@code Long.MIN_VALUE} if conversion would negatively
153			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
154			*/
155			public long convert(long sourceDuration, TimeUnit sourceUnit) {
156	dl	1.2	switch (this) {
157			case NANOSECONDS: return sourceUnit.toNanos(sourceDuration);
158			case MICROSECONDS: return sourceUnit.toMicros(sourceDuration);
159			case MILLISECONDS: return sourceUnit.toMillis(sourceDuration);
160			case SECONDS: return sourceUnit.toSeconds(sourceDuration);
161			default: return cvt(sourceDuration, scale, sourceUnit.scale);
162			}
163	jsr166	1.1	}
164
165			/**
166			* Equivalent to
167			* {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
168			* @param duration the duration
169			* @return the converted duration,
170			* or {@code Long.MIN_VALUE} if conversion would negatively
171			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
172			*/
173			public long toNanos(long duration) {
174			long s, m;
175			if ((s = scale) == NANO_SCALE)
176			return duration;
177			else if (duration > (m = maxNanos))
178			return Long.MAX_VALUE;
179			else if (duration < -m)
180			return Long.MIN_VALUE;
181			else
182			return duration * s;
183			}
184
185			/**
186			* Equivalent to
187			* {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
188			* @param duration the duration
189			* @return the converted duration,
190			* or {@code Long.MIN_VALUE} if conversion would negatively
191			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
192			*/
193			public long toMicros(long duration) {
194	dl	1.2	long s, m;
195			if ((s = scale) == MICRO_SCALE)
196			return duration;
197			else if (s < MICRO_SCALE)
198			return duration / microRatio;
199			else if (duration > (m = maxMicros))
200			return Long.MAX_VALUE;
201			else if (duration < -m)
202			return Long.MIN_VALUE;
203			else
204			return duration * microRatio;
205	jsr166	1.1	}
206
207			/**
208			* Equivalent to
209			* {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
210			* @param duration the duration
211			* @return the converted duration,
212			* or {@code Long.MIN_VALUE} if conversion would negatively
213			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
214			*/
215			public long toMillis(long duration) {
216			long s, m;
217			if ((s = scale) == MILLI_SCALE)
218			return duration;
219			else if (s < MILLI_SCALE)
220			return duration / milliRatio;
221			else if (duration > (m = maxMillis))
222			return Long.MAX_VALUE;
223			else if (duration < -m)
224			return Long.MIN_VALUE;
225			else
226			return duration * milliRatio;
227			}
228
229			/**
230			* Equivalent to
231			* {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
232			* @param duration the duration
233			* @return the converted duration,
234			* or {@code Long.MIN_VALUE} if conversion would negatively
235			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
236			*/
237			public long toSeconds(long duration) {
238			long s, m;
239			if ((s = scale) == SECOND_SCALE)
240			return duration;
241			else if (s < SECOND_SCALE)
242			return duration / secRatio;
243			else if (duration > (m = maxSecs))
244			return Long.MAX_VALUE;
245			else if (duration < -m)
246			return Long.MIN_VALUE;
247			else
248			return duration * secRatio;
249			}
250
251			/**
252			* Equivalent to
253			* {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
254			* @param duration the duration
255			* @return the converted duration,
256			* or {@code Long.MIN_VALUE} if conversion would negatively
257			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
258			* @since 1.6
259			*/
260			public long toMinutes(long duration) {
261			return cvt(duration, MINUTE_SCALE, scale);
262			}
263
264			/**
265			* Equivalent to
266			* {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
267			* @param duration the duration
268			* @return the converted duration,
269			* or {@code Long.MIN_VALUE} if conversion would negatively
270			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
271			* @since 1.6
272			*/
273			public long toHours(long duration) {
274			return cvt(duration, HOUR_SCALE, scale);
275			}
276
277			/**
278			* Equivalent to
279			* {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
280			* @param duration the duration
281			* @return the converted duration
282			* @since 1.6
283			*/
284			public long toDays(long duration) {
285			return cvt(duration, DAY_SCALE, scale);
286			}
287
288			/**
289			* Utility to compute the excess-nanosecond argument to wait,
290			* sleep, join.
291			* @param d the duration
292			* @param m the number of milliseconds
293			* @return the number of nanoseconds
294			*/
295			private int excessNanos(long d, long m) {
296			long s;
297			if ((s = scale) == NANO_SCALE)
298			return (int)(d - (m * MILLI_SCALE));
299			else if (s == MICRO_SCALE)
300			return (int)((d * 1000L) - (m * MILLI_SCALE));
301			else
302			return 0;
303			}
304
305			/**
306			* Performs a timed {@link Object#wait(long, int) Object.wait}
307			* using this time unit.
308			* This is a convenience method that converts timeout arguments
309			* into the form required by the {@code Object.wait} method.
310			*
311			* <p>For example, you could implement a blocking {@code poll}
312			* method (see {@link BlockingQueue#poll BlockingQueue.poll})
313			* using:
314			*
315			* <pre> {@code
316			* public synchronized Object poll(long timeout, TimeUnit unit)
317			* throws InterruptedException {
318			* while (empty) {
319			* unit.timedWait(this, timeout);
320			* ...
321			* }
322			* }}</pre>
323			*
324			* @param obj the object to wait on
325			* @param timeout the maximum time to wait. If less than
326			* or equal to zero, do not wait at all.
327			* @throws InterruptedException if interrupted while waiting
328			*/
329			public void timedWait(Object obj, long timeout)
330			throws InterruptedException {
331			if (timeout > 0) {
332			long ms = toMillis(timeout);
333			int ns = excessNanos(timeout, ms);
334			obj.wait(ms, ns);
335			}
336			}
337
338			/**
339			* Performs a timed {@link Thread#join(long, int) Thread.join}
340			* using this time unit.
341			* This is a convenience method that converts time arguments into the
342			* form required by the {@code Thread.join} method.
343			*
344			* @param thread the thread to wait for
345			* @param timeout the maximum time to wait. If less than
346			* or equal to zero, do not wait at all.
347			* @throws InterruptedException if interrupted while waiting
348			*/
349			public void timedJoin(Thread thread, long timeout)
350			throws InterruptedException {
351			if (timeout > 0) {
352			long ms = toMillis(timeout);
353			int ns = excessNanos(timeout, ms);
354			thread.join(ms, ns);
355			}
356			}
357
358			/**
359			* Performs a {@link Thread#sleep(long, int) Thread.sleep} using
360			* this time unit.
361			* This is a convenience method that converts time arguments into the
362			* form required by the {@code Thread.sleep} method.
363			*
364			* @param timeout the minimum time to sleep. If less than
365			* or equal to zero, do not sleep at all.
366			* @throws InterruptedException if interrupted while sleeping
367			*/
368			public void sleep(long timeout) throws InterruptedException {
369			if (timeout > 0) {
370			long ms = toMillis(timeout);
371			int ns = excessNanos(timeout, ms);
372			Thread.sleep(ms, ns);
373			}
374			}
375
376			/**
377			* Converts this {@code TimeUnit} to the equivalent {@code ChronoUnit}.
378			*
379			* @return the converted equivalent ChronoUnit
380			* @since 9
381			*/
382			public ChronoUnit toChronoUnit() {
383			switch (this) {
384			case NANOSECONDS: return ChronoUnit.NANOS;
385			case MICROSECONDS: return ChronoUnit.MICROS;
386			case MILLISECONDS: return ChronoUnit.MILLIS;
387			case SECONDS: return ChronoUnit.SECONDS;
388			case MINUTES: return ChronoUnit.MINUTES;
389			case HOURS: return ChronoUnit.HOURS;
390			case DAYS: return ChronoUnit.DAYS;
391			default: throw new AssertionError();
392			}
393			}
394
395			/**
396			* Converts a {@code ChronoUnit} to the equivalent {@code TimeUnit}.
397			*
398			* @param chronoUnit the ChronoUnit to convert
399			* @return the converted equivalent TimeUnit
400			* @throws IllegalArgumentException if {@code chronoUnit} has no
401			* equivalent TimeUnit
402			* @throws NullPointerException if {@code chronoUnit} is null
403			* @since 9
404			*/
405			public static TimeUnit of(ChronoUnit chronoUnit) {
406			switch (Objects.requireNonNull(chronoUnit, "chronoUnit")) {
407			case NANOS: return TimeUnit.NANOSECONDS;
408			case MICROS: return TimeUnit.MICROSECONDS;
409			case MILLIS: return TimeUnit.MILLISECONDS;
410			case SECONDS: return TimeUnit.SECONDS;
411			case MINUTES: return TimeUnit.MINUTES;
412			case HOURS: return TimeUnit.HOURS;
413			case DAYS: return TimeUnit.DAYS;
414			default:
415			throw new IllegalArgumentException(
416			"No TimeUnit equivalent for " + chronoUnit);
417			}
418			}
419
420			}