A 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: - * - *
Lock lock = ...; - * if (lock.tryLock(50L, TimeUnit.MILLISECONDS)) ... - *- * while this code will timeout in 50 seconds: - *
- * Lock lock = ...; - * if (lock.tryLock(50L, TimeUnit.SECONDS)) ... - *- * - * 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 TimeUnit. - * - * @since 1.5 - * @author Doug Lea - */ -public enum TimeUnit { - NANOSECONDS { - public long toNanos(long d) { return d; } - public long toMicros(long d) { return d/(C1/C0); } - public long toMillis(long d) { return d/(C2/C0); } - public long toSeconds(long d) { return d/(C3/C0); } - public long toMinutes(long d) { return d/(C4/C0); } - public long toHours(long d) { return d/(C5/C0); } - public long toDays(long d) { return d/(C6/C0); } - public long convert(long d, TimeUnit u) { return u.toNanos(d); } - int excessNanos(long d, long m) { return (int)(d - (m*C2)); } - }, - MICROSECONDS { - public long toNanos(long d) { return x(d, C1/C0, MAX/(C1/C0)); } - public long toMicros(long d) { return d; } - public long toMillis(long d) { return d/(C2/C1); } - public long toSeconds(long d) { return d/(C3/C1); } - public long toMinutes(long d) { return d/(C4/C1); } - public long toHours(long d) { return d/(C5/C1); } - public long toDays(long d) { return d/(C6/C1); } - public long convert(long d, TimeUnit u) { return u.toMicros(d); } - int excessNanos(long d, long m) { return (int)((d*C1) - (m*C2)); } - }, - MILLISECONDS { - public long toNanos(long d) { return x(d, C2/C0, MAX/(C2/C0)); } - public long toMicros(long d) { return x(d, C2/C1, MAX/(C2/C1)); } - public long toMillis(long d) { return d; } - public long toSeconds(long d) { return d/(C3/C2); } - public long toMinutes(long d) { return d/(C4/C2); } - public long toHours(long d) { return d/(C5/C2); } - public long toDays(long d) { return d/(C6/C2); } - public long convert(long d, TimeUnit u) { return u.toMillis(d); } - int excessNanos(long d, long m) { return 0; } - }, - SECONDS { - public long toNanos(long d) { return x(d, C3/C0, MAX/(C3/C0)); } - public long toMicros(long d) { return x(d, C3/C1, MAX/(C3/C1)); } - public long toMillis(long d) { return x(d, C3/C2, MAX/(C3/C2)); } - public long toSeconds(long d) { return d; } - public long toMinutes(long d) { return d/(C4/C3); } - public long toHours(long d) { return d/(C5/C3); } - public long toDays(long d) { return d/(C6/C3); } - public long convert(long d, TimeUnit u) { return u.toSeconds(d); } - int excessNanos(long d, long m) { return 0; } - }, - MINUTES { - public long toNanos(long d) { return x(d, C4/C0, MAX/(C4/C0)); } - public long toMicros(long d) { return x(d, C4/C1, MAX/(C4/C1)); } - public long toMillis(long d) { return x(d, C4/C2, MAX/(C4/C2)); } - public long toSeconds(long d) { return x(d, C4/C3, MAX/(C4/C3)); } - public long toMinutes(long d) { return d; } - public long toHours(long d) { return d/(C5/C4); } - public long toDays(long d) { return d/(C6/C4); } - public long convert(long d, TimeUnit u) { return u.toMinutes(d); } - int excessNanos(long d, long m) { return 0; } - }, - HOURS { - public long toNanos(long d) { return x(d, C5/C0, MAX/(C5/C0)); } - public long toMicros(long d) { return x(d, C5/C1, MAX/(C5/C1)); } - public long toMillis(long d) { return x(d, C5/C2, MAX/(C5/C2)); } - public long toSeconds(long d) { return x(d, C5/C3, MAX/(C5/C3)); } - public long toMinutes(long d) { return x(d, C5/C4, MAX/(C5/C4)); } - public long toHours(long d) { return d; } - public long toDays(long d) { return d/(C6/C5); } - public long convert(long d, TimeUnit u) { return u.toHours(d); } - int excessNanos(long d, long m) { return 0; } - }, - DAYS { - public long toNanos(long d) { return x(d, C6/C0, MAX/(C6/C0)); } - public long toMicros(long d) { return x(d, C6/C1, MAX/(C6/C1)); } - public long toMillis(long d) { return x(d, C6/C2, MAX/(C6/C2)); } - public long toSeconds(long d) { return x(d, C6/C3, MAX/(C6/C3)); } - public long toMinutes(long d) { return x(d, C6/C4, MAX/(C6/C4)); } - public long toHours(long d) { return x(d, C6/C5, MAX/(C6/C5)); } - public long toDays(long d) { return d; } - public long convert(long d, TimeUnit u) { return u.toDays(d); } - int excessNanos(long d, long m) { return 0; } - }; - - // Handy constants for conversion methods - static final long C0 = 1L; - static final long C1 = C0 * 1000L; - static final long C2 = C1 * 1000L; - static final long C3 = C2 * 1000L; - static final long C4 = C3 * 60L; - static final long C5 = C4 * 60L; - static final long C6 = C5 * 24L; - - static final long MAX = Long.MAX_VALUE; - - /** - * Scale d by m, checking for overflow. - * This has a short name to make above code more readable. - */ - static long x(long d, long m, long over) { - if (d > over) return Long.MAX_VALUE; - if (d < -over) return Long.MIN_VALUE; - return d * m; - } - - // To maintain full signature compatibility with 1.5, and to improve the - // clarity of the generated javadoc (see 6287639: Abstract methods in - // enum classes should not be listed as abstract), method convert - // etc. are not declared abstract but otherwise act as abstract methods. - - /** - * Convert the given time duration in the given unit to this - * unit. Conversions from finer to coarser granularities - * truncate, so lose precision. For example converting - * 999 milliseconds to seconds results in - * 0. Conversions from coarser to finer granularities - * with arguments that would numerically overflow saturate to - * Long.MIN_VALUE if negative or Long.MAX_VALUE - * if positive. - * - *
For example, to convert 10 minutes to milliseconds, use: - * TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES) - * - * @param sourceDuration the time duration in the given sourceUnit - * @param sourceUnit the unit of the sourceDuration argument - * @return the converted duration in this unit, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - */ - public long convert(long sourceDuration, TimeUnit sourceUnit) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to NANOSECONDS.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - */ - public long toNanos(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to MICROSECONDS.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - */ - public long toMicros(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to MILLISECONDS.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - */ - public long toMillis(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to SECONDS.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - */ - public long toSeconds(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to MINUTES.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - * @since 1.6 - */ - public long toMinutes(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to HOURS.convert(duration, this). - * @param duration the duration - * @return the converted duration, - * or Long.MIN_VALUE if conversion would negatively - * overflow, or Long.MAX_VALUE if it would positively overflow. - * @see #convert - * @since 1.6 - */ - public long toHours(long duration) { - throw new AbstractMethodError(); - } - - /** - * Equivalent to DAYS.convert(duration, this). - * @param duration the duration - * @return the converted duration - * @see #convert - * @since 1.6 - */ - public long toDays(long duration) { - throw new AbstractMethodError(); - } - - /** - * 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 - */ - abstract int excessNanos(long d, long m); - - /** - * 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 Object.wait method. - * - *
For example, you could implement a blocking poll - * method (see {@link BlockingQueue#poll BlockingQueue.poll}) - * using: - * - *
{@code
- * public synchronized Object poll(long timeout, TimeUnit unit)
- * throws InterruptedException {
- * while (empty) {
- * unit.timedWait(this, timeout);
- * ...
- * }
- * }}
- *
- * @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 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 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);
- Object o = new Object();
- synchronized (o) {
- o.wait(ms, ns);
- }
- }
- }
-
-}