| /* |
| * 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; |
| |
| /** |
| * A <tt>TimeUnit</tt> 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 |
| * <tt>TimeUnit</tt> 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 <tt>TimeUnit</tt> 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 <tt>TimeUnit</tt>. |
| * |
| * @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 |
| * <tt>999</tt> milliseconds to seconds results in |
| * <tt>0</tt>. Conversions from coarser to finer granularities |
| * with arguments that would numerically overflow saturate to |
| * <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt> |
| * if positive. |
| * |
| * <p>For example, to convert 10 minutes to milliseconds, use: |
| * <tt>TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)</tt> |
| * |
| * @param sourceDuration the time duration in the given <tt>sourceUnit</tt> |
| * @param sourceUnit the unit of the <tt>sourceDuration</tt> argument |
| * @return the converted duration in this unit, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| */ |
| public long convert(long sourceDuration, TimeUnit sourceUnit) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| */ |
| public long toNanos(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| */ |
| public long toMicros(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| */ |
| public long toMillis(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>SECONDS.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| */ |
| public long toSeconds(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>MINUTES.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| * @since 1.6 |
| */ |
| public long toMinutes(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>HOURS.convert(duration, this)</tt>. |
| * @param duration the duration |
| * @return the converted duration, |
| * or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| * overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
| * @see #convert |
| * @since 1.6 |
| */ |
| public long toHours(long duration) { |
| throw new AbstractMethodError(); |
| } |
| |
| /** |
| * Equivalent to <tt>DAYS.convert(duration, this)</tt>. |
| * @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 <tt>Object.wait</tt> method. |
| * |
| * <p>For example, you could implement a blocking <tt>poll</tt> |
| * 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 <tt>Thread.join</tt> 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 <tt>Thread.sleep</tt> 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); |
| } |
| } |
| |
| } |
