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 two units commonly used for JDK timing, used in methods
     * toNanos and toMillis. Other cases compute them, in method cvt.
     */

    private final long scale;
    private final long maxNanos;
    private final long millisRatio;
    private final long maxMillis;

    TimeUnit(long scale) {
        this.scale = scale;
        this.maxNanos = Long.MAX_VALUE / scale;
        long r = (scale >= MILLI_SCALE ? scale / MILLI_SCALE :
                  MILLI_SCALE / scale);
        this.millisRatio = r;
        this.maxMillis = Long.MAX_VALUE / r;
    }

    /**
     * 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;
        return ((src == dst) ? d :
                (src < dst) ? d / (dst / src) :
                (d > (m = Long.MAX_VALUE / (r = src / dst))) ? Long.MAX_VALUE :
                (d < -m) ? Long.MIN_VALUE :
                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) {
        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;
        return (((s = scale) == NANO_SCALE) ? duration :
                (duration > (m = maxNanos)) ? Long.MAX_VALUE :
                (duration < -m) ? Long.MIN_VALUE :
                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) {
        return cvt(duration, MICRO_SCALE, scale);
    }

    /**
     * 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;
        return ( ((s = scale) == MILLI_SCALE) ? duration :
                 (s < MILLI_SCALE) ? duration / millisRatio :
                 (duration > (m = maxMillis)) ? Long.MAX_VALUE :
                 (duration < -m) ? Long.MIN_VALUE :
                 duration * millisRatio);
    }

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

    /**
     * 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;
        return (((s = scale) == NANO_SCALE) ? (int)(d - (m * MILLI_SCALE)) :
                (s == MICRO_SCALE) ? (int)((d * 1000L) - (m * MILLI_SCALE)) :
                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:	1.49
Committed:	Wed Mar 23 14:03:06 2016 UTC (8 years, 2 months ago) by dl
Branch:	MAIN
Changes since 1.48:	+75 -118 lines
Log Message:	Avoid megamorphic dispatch
#	User	Rev	Content
1	dl	1.2	/*
2	jsr166	1.35	* 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	jsr166	1.38	* http://creativecommons.org/publicdomain/zero/1.0/
5	jsr166	1.35	*/
6	dl	1.2
7	tim	1.1	package java.util.concurrent;
8
9	jsr166	1.48	import java.time.temporal.ChronoUnit;
10			import java.util.Objects;
11
12	tim	1.1	/**
13	jsr166	1.40	* A {@code TimeUnit} represents time durations at a given unit of
14	dl	1.27	* granularity and provides utility methods to convert across units,
15			* and to perform timing and delay operations in these units. A
16	jsr166	1.40	* {@code TimeUnit} does not maintain time information, but only
17	dl	1.27	* 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	jsr166	1.40	* <p>A {@code TimeUnit} is mainly used to inform time-based methods
25	dl	1.27	* 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	jsr166	1.45	* <pre> {@code
30	jsr166	1.39	* Lock lock = ...;
31			* if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ...}</pre>
32			*
33	dl	1.27	* while this code will timeout in 50 seconds:
34	jsr166	1.45	* <pre> {@code
35	jsr166	1.39	* Lock lock = ...;
36			* if (lock.tryLock(50L, TimeUnit.SECONDS)) ...}</pre>
37	dl	1.27	*
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	jsr166	1.40	* same granularity as the given {@code TimeUnit}.
41	dl	1.27	*
42			* @since 1.5
43			* @author Doug Lea
44			*/
45	dl	1.20	public enum TimeUnit {
46	jsr166	1.43	/**
47	jsr166	1.47	* Time unit representing one thousandth of a microsecond.
48	jsr166	1.43	*/
49	dl	1.49	NANOSECONDS(1L), // (cannot use symbolic scale names here)
50	jsr166	1.43	/**
51	jsr166	1.47	* Time unit representing one thousandth of a millisecond.
52	jsr166	1.43	*/
53	dl	1.49	MICROSECONDS(1000L),
54	jsr166	1.43	/**
55	jsr166	1.47	* Time unit representing one thousandth of a second.
56	jsr166	1.43	*/
57	dl	1.49	MILLISECONDS(1000L * 1000L),
58	jsr166	1.43	/**
59	jsr166	1.47	* Time unit representing one second.
60	jsr166	1.43	*/
61	dl	1.49	SECONDS(1000L * 1000L * 1000L),
62	jsr166	1.43	/**
63	jsr166	1.47	* Time unit representing sixty seconds.
64	jsr166	1.44	* @since 1.6
65	jsr166	1.43	*/
66	dl	1.49	MINUTES(1000L * 1000L * 1000L * 60L),
67	jsr166	1.43	/**
68	jsr166	1.47	* Time unit representing sixty minutes.
69	jsr166	1.44	* @since 1.6
70	jsr166	1.43	*/
71	dl	1.49	HOURS(1000L * 1000L * 1000L * 60L * 60L),
72	jsr166	1.43	/**
73	jsr166	1.47	* Time unit representing twenty four hours.
74	jsr166	1.44	* @since 1.6
75	jsr166	1.43	*/
76	dl	1.49	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			* the two units commonly used for JDK timing, used in methods
90			* toNanos and toMillis. Other cases compute them, in method cvt.
91			*/
92
93			private final long scale;
94			private final long maxNanos;
95			private final long millisRatio;
96			private final long maxMillis;
97
98			TimeUnit(long scale) {
99			this.scale = scale;
100			this.maxNanos = Long.MAX_VALUE / scale;
101			long r = (scale >= MILLI_SCALE ? scale / MILLI_SCALE :
102			MILLI_SCALE / scale);
103			this.millisRatio = r;
104			this.maxMillis = Long.MAX_VALUE / r;
105			}
106
107			/**
108			* General conversion utility.
109			*
110			* @param d duration
111			* @param dst result scale unit
112			* @param src source scale unit
113			*/
114			private static long cvt(long d, long dst, long src) {
115			long r, m;
116			return ((src == dst) ? d :
117			(src < dst) ? d / (dst / src) :
118			(d > (m = Long.MAX_VALUE / (r = src / dst))) ? Long.MAX_VALUE :
119			(d < -m) ? Long.MIN_VALUE :
120			d * r);
121			}
122	dl	1.32
123	dl	1.27	/**
124	jsr166	1.42	* Converts the given time duration in the given unit to this unit.
125			* Conversions from finer to coarser granularities truncate, so
126			* lose precision. For example, converting {@code 999} milliseconds
127			* to seconds results in {@code 0}. Conversions from coarser to
128			* finer granularities with arguments that would numerically
129			* overflow saturate to {@code Long.MIN_VALUE} if negative or
130			* {@code Long.MAX_VALUE} if positive.
131	jsr166	1.33	*
132			* <p>For example, to convert 10 minutes to milliseconds, use:
133	jsr166	1.40	* {@code TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)}
134	dl	1.27	*
135	jsr166	1.40	* @param sourceDuration the time duration in the given {@code sourceUnit}
136			* @param sourceUnit the unit of the {@code sourceDuration} argument
137	dl	1.27	* @return the converted duration in this unit,
138	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
139			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
140	dl	1.27	*/
141	dl	1.32	public long convert(long sourceDuration, TimeUnit sourceUnit) {
142	dl	1.49	return cvt(sourceDuration, scale, sourceUnit.scale);
143	dl	1.32	}
144	jsr166	1.29
145	dl	1.27	/**
146	jsr166	1.41	* Equivalent to
147			* {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
148	dl	1.27	* @param duration the duration
149			* @return the converted duration,
150	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
151			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
152	dl	1.27	*/
153	dl	1.32	public long toNanos(long duration) {
154	dl	1.49	long s, m;
155			return (((s = scale) == NANO_SCALE) ? duration :
156			(duration > (m = maxNanos)) ? Long.MAX_VALUE :
157			(duration < -m) ? Long.MIN_VALUE :
158			duration * s);
159	dl	1.32	}
160	jsr166	1.29
161	dl	1.27	/**
162	jsr166	1.41	* Equivalent to
163			* {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
164	dl	1.27	* @param duration the duration
165			* @return the converted duration,
166	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
167			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
168	dl	1.27	*/
169	dl	1.32	public long toMicros(long duration) {
170	dl	1.49	return cvt(duration, MICRO_SCALE, scale);
171	dl	1.32	}
172	jsr166	1.29
173	dl	1.27	/**
174	jsr166	1.41	* Equivalent to
175			* {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
176	dl	1.27	* @param duration the duration
177			* @return the converted duration,
178	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
179			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
180	dl	1.27	*/
181	dl	1.32	public long toMillis(long duration) {
182	dl	1.49	long s, m;
183			return ( ((s = scale) == MILLI_SCALE) ? duration :
184			(s < MILLI_SCALE) ? duration / millisRatio :
185			(duration > (m = maxMillis)) ? Long.MAX_VALUE :
186			(duration < -m) ? Long.MIN_VALUE :
187			duration * millisRatio);
188	dl	1.32	}
189	jsr166	1.29
190	dl	1.27	/**
191	jsr166	1.41	* Equivalent to
192			* {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
193	dl	1.27	* @param duration the duration
194			* @return the converted duration,
195	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
196			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
197	dl	1.27	*/
198	dl	1.32	public long toSeconds(long duration) {
199	dl	1.49	return cvt(duration, SECOND_SCALE, scale);
200	dl	1.32	}
201	jsr166	1.29
202	dl	1.27	/**
203	jsr166	1.41	* Equivalent to
204			* {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
205	dl	1.27	* @param duration the duration
206			* @return the converted duration,
207	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
208			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
209	dl	1.31	* @since 1.6
210	dl	1.27	*/
211	dl	1.32	public long toMinutes(long duration) {
212	dl	1.49	return cvt(duration, MINUTE_SCALE, scale);
213	dl	1.32	}
214	jsr166	1.29
215	dl	1.27	/**
216	jsr166	1.41	* Equivalent to
217			* {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
218	dl	1.27	* @param duration the duration
219			* @return the converted duration,
220	jsr166	1.40	* or {@code Long.MIN_VALUE} if conversion would negatively
221			* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
222	dl	1.31	* @since 1.6
223	dl	1.27	*/
224	dl	1.32	public long toHours(long duration) {
225	dl	1.49	return cvt(duration, HOUR_SCALE, scale);
226	dl	1.32	}
227	jsr166	1.29
228	dl	1.27	/**
229	jsr166	1.41	* Equivalent to
230			* {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
231	dl	1.27	* @param duration the duration
232			* @return the converted duration
233	dl	1.31	* @since 1.6
234	dl	1.27	*/
235	dl	1.32	public long toDays(long duration) {
236	dl	1.49	return cvt(duration, DAY_SCALE, scale);
237	dl	1.32	}
238	jsr166	1.29
239	dl	1.27	/**
240			* Utility to compute the excess-nanosecond argument to wait,
241			* sleep, join.
242			* @param d the duration
243			* @param m the number of milliseconds
244			* @return the number of nanoseconds
245			*/
246	dl	1.49	private int excessNanos(long d, long m) {
247			long s;
248			return (((s = scale) == NANO_SCALE) ? (int)(d - (m * MILLI_SCALE)) :
249			(s == MICRO_SCALE) ? (int)((d * 1000L) - (m * MILLI_SCALE)) :
250			0);
251			}
252	jsr166	1.29
253	dl	1.27	/**
254	jsr166	1.37	* Performs a timed {@link Object#wait(long, int) Object.wait}
255			* using this time unit.
256	dl	1.27	* This is a convenience method that converts timeout arguments
257	jsr166	1.40	* into the form required by the {@code Object.wait} method.
258	dl	1.27	*
259	jsr166	1.40	* <p>For example, you could implement a blocking {@code poll}
260	dl	1.27	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
261			* using:
262			*
263	jsr166	1.45	* <pre> {@code
264	jsr166	1.36	* public synchronized Object poll(long timeout, TimeUnit unit)
265			* throws InterruptedException {
266			* while (empty) {
267			* unit.timedWait(this, timeout);
268			* ...
269			* }
270			* }}</pre>
271	dl	1.27	*
272			* @param obj the object to wait on
273	dl	1.28	* @param timeout the maximum time to wait. If less than
274			* or equal to zero, do not wait at all.
275	jsr166	1.37	* @throws InterruptedException if interrupted while waiting
276	dl	1.27	*/
277			public void timedWait(Object obj, long timeout)
278	jsr166	1.37	throws InterruptedException {
279	dl	1.27	if (timeout > 0) {
280			long ms = toMillis(timeout);
281			int ns = excessNanos(timeout, ms);
282			obj.wait(ms, ns);
283			}
284			}
285	jsr166	1.29
286	dl	1.27	/**
287	jsr166	1.37	* Performs a timed {@link Thread#join(long, int) Thread.join}
288			* using this time unit.
289	dl	1.27	* This is a convenience method that converts time arguments into the
290	jsr166	1.40	* form required by the {@code Thread.join} method.
291	jsr166	1.37	*
292	dl	1.27	* @param thread the thread to wait for
293	dl	1.28	* @param timeout the maximum time to wait. If less than
294			* or equal to zero, do not wait at all.
295	jsr166	1.37	* @throws InterruptedException if interrupted while waiting
296	dl	1.27	*/
297			public void timedJoin(Thread thread, long timeout)
298	jsr166	1.37	throws InterruptedException {
299	dl	1.27	if (timeout > 0) {
300			long ms = toMillis(timeout);
301			int ns = excessNanos(timeout, ms);
302			thread.join(ms, ns);
303			}
304			}
305	jsr166	1.29
306	dl	1.27	/**
307	jsr166	1.37	* Performs a {@link Thread#sleep(long, int) Thread.sleep} using
308			* this time unit.
309	dl	1.27	* This is a convenience method that converts time arguments into the
310	jsr166	1.40	* form required by the {@code Thread.sleep} method.
311	jsr166	1.37	*
312	dl	1.28	* @param timeout the minimum time to sleep. If less than
313			* or equal to zero, do not sleep at all.
314	jsr166	1.37	* @throws InterruptedException if interrupted while sleeping
315	dl	1.27	*/
316			public void sleep(long timeout) throws InterruptedException {
317			if (timeout > 0) {
318			long ms = toMillis(timeout);
319			int ns = excessNanos(timeout, ms);
320			Thread.sleep(ms, ns);
321			}
322			}
323	jsr166	1.29
324	jsr166	1.48	/**
325			* Converts this {@code TimeUnit} to the equivalent {@code ChronoUnit}.
326			*
327			* @return the converted equivalent ChronoUnit
328			* @since 9
329			*/
330			public ChronoUnit toChronoUnit() {
331			switch (this) {
332			case NANOSECONDS: return ChronoUnit.NANOS;
333			case MICROSECONDS: return ChronoUnit.MICROS;
334			case MILLISECONDS: return ChronoUnit.MILLIS;
335			case SECONDS: return ChronoUnit.SECONDS;
336			case MINUTES: return ChronoUnit.MINUTES;
337			case HOURS: return ChronoUnit.HOURS;
338			case DAYS: return ChronoUnit.DAYS;
339			default: throw new AssertionError();
340			}
341			}
342
343			/**
344			* Converts a {@code ChronoUnit} to the equivalent {@code TimeUnit}.
345			*
346			* @param chronoUnit the ChronoUnit to convert
347			* @return the converted equivalent TimeUnit
348			* @throws IllegalArgumentException if {@code chronoUnit} has no
349			* equivalent TimeUnit
350			* @throws NullPointerException if {@code chronoUnit} is null
351			* @since 9
352			*/
353			public static TimeUnit of(ChronoUnit chronoUnit) {
354			switch (Objects.requireNonNull(chronoUnit, "chronoUnit")) {
355			case NANOS: return TimeUnit.NANOSECONDS;
356			case MICROS: return TimeUnit.MICROSECONDS;
357			case MILLIS: return TimeUnit.MILLISECONDS;
358			case SECONDS: return TimeUnit.SECONDS;
359			case MINUTES: return TimeUnit.MINUTES;
360			case HOURS: return TimeUnit.HOURS;
361			case DAYS: return TimeUnit.DAYS;
362			default:
363			throw new IllegalArgumentException(
364			"No TimeUnit equivalent for " + chronoUnit);
365			}
366			}
367
368	tim	1.1	}