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
#	Content
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	* 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
123	/**
124	* 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	*
132	* <p>For example, to convert 10 minutes to milliseconds, use:
133	* {@code TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)}
134	*
135	* @param sourceDuration the time duration in the given {@code sourceUnit}
136	* @param sourceUnit the unit of the {@code sourceDuration} argument
137	* @return the converted duration in this unit,
138	* or {@code Long.MIN_VALUE} if conversion would negatively
139	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
140	*/
141	public long convert(long sourceDuration, TimeUnit sourceUnit) {
142	return cvt(sourceDuration, scale, sourceUnit.scale);
143	}
144
145	/**
146	* Equivalent to
147	* {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
148	* @param duration the duration
149	* @return the converted duration,
150	* or {@code Long.MIN_VALUE} if conversion would negatively
151	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
152	*/
153	public long toNanos(long duration) {
154	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	}
160
161	/**
162	* Equivalent to
163	* {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
164	* @param duration the duration
165	* @return the converted duration,
166	* or {@code Long.MIN_VALUE} if conversion would negatively
167	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
168	*/
169	public long toMicros(long duration) {
170	return cvt(duration, MICRO_SCALE, scale);
171	}
172
173	/**
174	* Equivalent to
175	* {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
176	* @param duration the duration
177	* @return the converted duration,
178	* or {@code Long.MIN_VALUE} if conversion would negatively
179	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
180	*/
181	public long toMillis(long duration) {
182	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	}
189
190	/**
191	* Equivalent to
192	* {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
193	* @param duration the duration
194	* @return the converted duration,
195	* or {@code Long.MIN_VALUE} if conversion would negatively
196	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
197	*/
198	public long toSeconds(long duration) {
199	return cvt(duration, SECOND_SCALE, scale);
200	}
201
202	/**
203	* Equivalent to
204	* {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
205	* @param duration the duration
206	* @return the converted duration,
207	* or {@code Long.MIN_VALUE} if conversion would negatively
208	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
209	* @since 1.6
210	*/
211	public long toMinutes(long duration) {
212	return cvt(duration, MINUTE_SCALE, scale);
213	}
214
215	/**
216	* Equivalent to
217	* {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
218	* @param duration the duration
219	* @return the converted duration,
220	* or {@code Long.MIN_VALUE} if conversion would negatively
221	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
222	* @since 1.6
223	*/
224	public long toHours(long duration) {
225	return cvt(duration, HOUR_SCALE, scale);
226	}
227
228	/**
229	* Equivalent to
230	* {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
231	* @param duration the duration
232	* @return the converted duration
233	* @since 1.6
234	*/
235	public long toDays(long duration) {
236	return cvt(duration, DAY_SCALE, scale);
237	}
238
239	/**
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	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
253	/**
254	* Performs a timed {@link Object#wait(long, int) Object.wait}
255	* using this time unit.
256	* This is a convenience method that converts timeout arguments
257	* into the form required by the {@code Object.wait} method.
258	*
259	* <p>For example, you could implement a blocking {@code poll}
260	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
261	* using:
262	*
263	* <pre> {@code
264	* public synchronized Object poll(long timeout, TimeUnit unit)
265	* throws InterruptedException {
266	* while (empty) {
267	* unit.timedWait(this, timeout);
268	* ...
269	* }
270	* }}</pre>
271	*
272	* @param obj the object to wait on
273	* @param timeout the maximum time to wait. If less than
274	* or equal to zero, do not wait at all.
275	* @throws InterruptedException if interrupted while waiting
276	*/
277	public void timedWait(Object obj, long timeout)
278	throws InterruptedException {
279	if (timeout > 0) {
280	long ms = toMillis(timeout);
281	int ns = excessNanos(timeout, ms);
282	obj.wait(ms, ns);
283	}
284	}
285
286	/**
287	* Performs a timed {@link Thread#join(long, int) Thread.join}
288	* using this time unit.
289	* This is a convenience method that converts time arguments into the
290	* form required by the {@code Thread.join} method.
291	*
292	* @param thread the thread to wait for
293	* @param timeout the maximum time to wait. If less than
294	* or equal to zero, do not wait at all.
295	* @throws InterruptedException if interrupted while waiting
296	*/
297	public void timedJoin(Thread thread, long timeout)
298	throws InterruptedException {
299	if (timeout > 0) {
300	long ms = toMillis(timeout);
301	int ns = excessNanos(timeout, ms);
302	thread.join(ms, ns);
303	}
304	}
305
306	/**
307	* Performs a {@link Thread#sleep(long, int) Thread.sleep} using
308	* this time unit.
309	* This is a convenience method that converts time arguments into the
310	* form required by the {@code Thread.sleep} method.
311	*
312	* @param timeout the minimum time to sleep. If less than
313	* or equal to zero, do not sleep at all.
314	* @throws InterruptedException if interrupted while sleeping
315	*/
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
324	/**
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	}