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 most commonly used in conversion results, in methods
     * toNanos, toMillis and toSeconds. Other cases compute them, in
     * method cvt.
     */

    private final long scale;
    private final long maxNanos;
    private final long maxMillis;
    private final long maxSecs;
    private final int milliRatio;
    private final int secRatio;

    TimeUnit(long scale) {
        this.scale = scale;
        this.maxNanos = Long.MAX_VALUE / scale;
        long mr = (scale >= MILLI_SCALE)
            ? (scale / MILLI_SCALE)
            : (MILLI_SCALE / scale);
        this.milliRatio = (int)mr;
        this.maxMillis = Long.MAX_VALUE / mr;
        long sr = (scale >= SECOND_SCALE)
            ? (scale / SECOND_SCALE)
            : (SECOND_SCALE / scale);
        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) {
        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) {
        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;
        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:	1.1
Committed:	Sat Mar 26 06:22:50 2016 UTC (8 years, 2 months ago) by jsr166
Branch:	MAIN
Log Message:	fork jdk8 maintenance branch for source and jtreg tests
#	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 units most commonly used in conversion results, in methods
90	* toNanos, toMillis and toSeconds. Other cases compute them, in
91	* method cvt.
92	*/
93
94	private final long scale;
95	private final long maxNanos;
96	private final long maxMillis;
97	private final long maxSecs;
98	private final int milliRatio;
99	private final int secRatio;
100
101	TimeUnit(long scale) {
102	this.scale = scale;
103	this.maxNanos = Long.MAX_VALUE / scale;
104	long mr = (scale >= MILLI_SCALE)
105	? (scale / MILLI_SCALE)
106	: (MILLI_SCALE / scale);
107	this.milliRatio = (int)mr;
108	this.maxMillis = Long.MAX_VALUE / mr;
109	long sr = (scale >= SECOND_SCALE)
110	? (scale / SECOND_SCALE)
111	: (SECOND_SCALE / scale);
112	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	return cvt(sourceDuration, scale, sourceUnit.scale);
157	}
158
159	/**
160	* Equivalent to
161	* {@link #convert(long, TimeUnit) NANOSECONDS.convert(duration, this)}.
162	* @param duration the duration
163	* @return the converted duration,
164	* or {@code Long.MIN_VALUE} if conversion would negatively
165	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
166	*/
167	public long toNanos(long duration) {
168	long s, m;
169	if ((s = scale) == NANO_SCALE)
170	return duration;
171	else if (duration > (m = maxNanos))
172	return Long.MAX_VALUE;
173	else if (duration < -m)
174	return Long.MIN_VALUE;
175	else
176	return duration * s;
177	}
178
179	/**
180	* Equivalent to
181	* {@link #convert(long, TimeUnit) MICROSECONDS.convert(duration, this)}.
182	* @param duration the duration
183	* @return the converted duration,
184	* or {@code Long.MIN_VALUE} if conversion would negatively
185	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
186	*/
187	public long toMicros(long duration) {
188	return cvt(duration, MICRO_SCALE, scale);
189	}
190
191	/**
192	* Equivalent to
193	* {@link #convert(long, TimeUnit) MILLISECONDS.convert(duration, this)}.
194	* @param duration the duration
195	* @return the converted duration,
196	* or {@code Long.MIN_VALUE} if conversion would negatively
197	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
198	*/
199	public long toMillis(long duration) {
200	long s, m;
201	if ((s = scale) == MILLI_SCALE)
202	return duration;
203	else if (s < MILLI_SCALE)
204	return duration / milliRatio;
205	else if (duration > (m = maxMillis))
206	return Long.MAX_VALUE;
207	else if (duration < -m)
208	return Long.MIN_VALUE;
209	else
210	return duration * milliRatio;
211	}
212
213	/**
214	* Equivalent to
215	* {@link #convert(long, TimeUnit) SECONDS.convert(duration, this)}.
216	* @param duration the duration
217	* @return the converted duration,
218	* or {@code Long.MIN_VALUE} if conversion would negatively
219	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
220	*/
221	public long toSeconds(long duration) {
222	long s, m;
223	if ((s = scale) == SECOND_SCALE)
224	return duration;
225	else if (s < SECOND_SCALE)
226	return duration / secRatio;
227	else if (duration > (m = maxSecs))
228	return Long.MAX_VALUE;
229	else if (duration < -m)
230	return Long.MIN_VALUE;
231	else
232	return duration * secRatio;
233	}
234
235	/**
236	* Equivalent to
237	* {@link #convert(long, TimeUnit) MINUTES.convert(duration, this)}.
238	* @param duration the duration
239	* @return the converted duration,
240	* or {@code Long.MIN_VALUE} if conversion would negatively
241	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
242	* @since 1.6
243	*/
244	public long toMinutes(long duration) {
245	return cvt(duration, MINUTE_SCALE, scale);
246	}
247
248	/**
249	* Equivalent to
250	* {@link #convert(long, TimeUnit) HOURS.convert(duration, this)}.
251	* @param duration the duration
252	* @return the converted duration,
253	* or {@code Long.MIN_VALUE} if conversion would negatively
254	* overflow, or {@code Long.MAX_VALUE} if it would positively overflow.
255	* @since 1.6
256	*/
257	public long toHours(long duration) {
258	return cvt(duration, HOUR_SCALE, scale);
259	}
260
261	/**
262	* Equivalent to
263	* {@link #convert(long, TimeUnit) DAYS.convert(duration, this)}.
264	* @param duration the duration
265	* @return the converted duration
266	* @since 1.6
267	*/
268	public long toDays(long duration) {
269	return cvt(duration, DAY_SCALE, scale);
270	}
271
272	/**
273	* Utility to compute the excess-nanosecond argument to wait,
274	* sleep, join.
275	* @param d the duration
276	* @param m the number of milliseconds
277	* @return the number of nanoseconds
278	*/
279	private int excessNanos(long d, long m) {
280	long s;
281	if ((s = scale) == NANO_SCALE)
282	return (int)(d - (m * MILLI_SCALE));
283	else if (s == MICRO_SCALE)
284	return (int)((d * 1000L) - (m * MILLI_SCALE));
285	else
286	return 0;
287	}
288
289	/**
290	* Performs a timed {@link Object#wait(long, int) Object.wait}
291	* using this time unit.
292	* This is a convenience method that converts timeout arguments
293	* into the form required by the {@code Object.wait} method.
294	*
295	* <p>For example, you could implement a blocking {@code poll}
296	* method (see {@link BlockingQueue#poll BlockingQueue.poll})
297	* using:
298	*
299	* <pre> {@code
300	* public synchronized Object poll(long timeout, TimeUnit unit)
301	* throws InterruptedException {
302	* while (empty) {
303	* unit.timedWait(this, timeout);
304	* ...
305	* }
306	* }}</pre>
307	*
308	* @param obj the object to wait on
309	* @param timeout the maximum time to wait. If less than
310	* or equal to zero, do not wait at all.
311	* @throws InterruptedException if interrupted while waiting
312	*/
313	public void timedWait(Object obj, long timeout)
314	throws InterruptedException {
315	if (timeout > 0) {
316	long ms = toMillis(timeout);
317	int ns = excessNanos(timeout, ms);
318	obj.wait(ms, ns);
319	}
320	}
321
322	/**
323	* Performs a timed {@link Thread#join(long, int) Thread.join}
324	* using this time unit.
325	* This is a convenience method that converts time arguments into the
326	* form required by the {@code Thread.join} method.
327	*
328	* @param thread the thread to wait for
329	* @param timeout the maximum time to wait. If less than
330	* or equal to zero, do not wait at all.
331	* @throws InterruptedException if interrupted while waiting
332	*/
333	public void timedJoin(Thread thread, long timeout)
334	throws InterruptedException {
335	if (timeout > 0) {
336	long ms = toMillis(timeout);
337	int ns = excessNanos(timeout, ms);
338	thread.join(ms, ns);
339	}
340	}
341
342	/**
343	* Performs a {@link Thread#sleep(long, int) Thread.sleep} using
344	* this time unit.
345	* This is a convenience method that converts time arguments into the
346	* form required by the {@code Thread.sleep} method.
347	*
348	* @param timeout the minimum time to sleep. If less than
349	* or equal to zero, do not sleep at all.
350	* @throws InterruptedException if interrupted while sleeping
351	*/
352	public void sleep(long timeout) throws InterruptedException {
353	if (timeout > 0) {
354	long ms = toMillis(timeout);
355	int ns = excessNanos(timeout, ms);
356	Thread.sleep(ms, ns);
357	}
358	}
359
360	/**
361	* Converts this {@code TimeUnit} to the equivalent {@code ChronoUnit}.
362	*
363	* @return the converted equivalent ChronoUnit
364	* @since 9
365	*/
366	public ChronoUnit toChronoUnit() {
367	switch (this) {
368	case NANOSECONDS: return ChronoUnit.NANOS;
369	case MICROSECONDS: return ChronoUnit.MICROS;
370	case MILLISECONDS: return ChronoUnit.MILLIS;
371	case SECONDS: return ChronoUnit.SECONDS;
372	case MINUTES: return ChronoUnit.MINUTES;
373	case HOURS: return ChronoUnit.HOURS;
374	case DAYS: return ChronoUnit.DAYS;
375	default: throw new AssertionError();
376	}
377	}
378
379	/**
380	* Converts a {@code ChronoUnit} to the equivalent {@code TimeUnit}.
381	*
382	* @param chronoUnit the ChronoUnit to convert
383	* @return the converted equivalent TimeUnit
384	* @throws IllegalArgumentException if {@code chronoUnit} has no
385	* equivalent TimeUnit
386	* @throws NullPointerException if {@code chronoUnit} is null
387	* @since 9
388	*/
389	public static TimeUnit of(ChronoUnit chronoUnit) {
390	switch (Objects.requireNonNull(chronoUnit, "chronoUnit")) {
391	case NANOS: return TimeUnit.NANOSECONDS;
392	case MICROS: return TimeUnit.MICROSECONDS;
393	case MILLIS: return TimeUnit.MILLISECONDS;
394	case SECONDS: return TimeUnit.SECONDS;
395	case MINUTES: return TimeUnit.MINUTES;
396	case HOURS: return TimeUnit.HOURS;
397	case DAYS: return TimeUnit.DAYS;
398	default:
399	throw new IllegalArgumentException(
400	"No TimeUnit equivalent for " + chronoUnit);
401	}
402	}
403
404	}