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/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain. Use, modify, and |
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* redistribute this code in any way without acknowledgement. |
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*/ |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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* http://creativecommons.org/licenses/publicdomain |
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*/ |
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package java.util.concurrent; |
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/** |
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* A <tt>TimeUnit</tt> represents time durations at a given unit of |
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* granularity and provides utility methods to convert across units, |
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* and to perform timing and delay operations in these units. |
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* <tt>TimeUnit</tt> is a "featherweight" class. |
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* It does not maintain time information, but only helps organize and |
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* use time representations that may be maintained separately across |
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* various contexts. |
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* and to perform timing and delay operations in these units. A |
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* <tt>TimeUnit</tt> does not maintain time information, but only |
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* helps organize and use time representations that may be maintained |
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* separately across various contexts. A nanosecond is defined as one |
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* thousandth of a microsecond, a microsecond as one thousandth of a |
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* millisecond, a millisecond as one thousandth of a second, a minute |
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* as sixty seconds, an hour as sixty minutes, and a day as twenty four |
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* hours. |
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* |
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* <p>This class cannot be directly instantiated. Use the {@link |
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* #SECONDS}, {@link #MILLISECONDS}, {@link #MICROSECONDS}, and {@link |
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* #NANOSECONDS} static instances that provide predefined units of |
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* precision. If you use these frequently, consider statically |
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* importing this class. |
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* <p>A <tt>TimeUnit</tt> is mainly used to inform time-based methods |
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* how a given timing parameter should be interpreted. For example, |
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* the following code will timeout in 50 milliseconds if the {@link |
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* java.util.concurrent.locks.Lock lock} is not available: |
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* |
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* <p>A <tt>TimeUnit</tt> is mainly used to inform blocking methods which |
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* can timeout, how the timeout parameter should be interpreted. For example, |
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* the following code will timeout in 50 milliseconds if the {@link java.util.concurrent.locks.Lock lock} |
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* is not available: |
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* <pre> Lock lock = ...; |
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* if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ... |
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* </pre> |
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* Lock lock = ...; |
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* if ( lock.tryLock(50L, TimeUnit.SECONDS) ) ... |
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* </pre> |
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* Note however, that there is no guarantee that a particular lock, in this |
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* case, will be able to notice the passage of time at the same granularity |
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* as the given <tt>TimeUnit</tt>. |
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* |
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* Note however, that there is no guarantee that a particular timeout |
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* implementation will be able to notice the passage of time at the |
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* same granularity as the given <tt>TimeUnit</tt>. |
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* |
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* @since 1.5 |
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* @author Doug Lea |
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*/ |
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public final class TimeUnit implements java.io.Serializable { |
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|
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/** |
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* Perform the conversion based on given index representing the |
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* difference between units |
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* @param delta the difference in index values of source and target units |
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* @param duration the duration |
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* @return converted duration or saturated value |
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*/ |
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private static long doConvert(int delta, long duration) { |
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if (delta == 0) |
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return duration; |
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if (delta < 0) |
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return duration / multipliers[-delta]; |
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if (duration > overflows[delta]) |
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return Long.MAX_VALUE; |
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if (duration < -overflows[delta]) |
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return Long.MIN_VALUE; |
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return duration * multipliers[delta]; |
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public enum TimeUnit { |
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NANOSECONDS (0) { |
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public long toNanos(long d) { return d; } |
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public long toMicros(long d) { return d/(C1/C0); } |
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public long toMillis(long d) { return d/(C2/C0); } |
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public long toSeconds(long d) { return d/(C3/C0); } |
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public long toMinutes(long d) { return d/(C4/C0); } |
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public long toHours(long d) { return d/(C5/C0); } |
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public long toDays(long d) { return d/(C6/C0); } |
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public long convert(long d, TimeUnit u) { return u.toNanos(d); } |
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int excessNanos(long d, long m) { return (int)(d - (m*C2)); } |
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}, |
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MICROSECONDS (1) { |
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public long toNanos(long d) { return x(d, C1/C0, MAX/(C1/C0)); } |
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public long toMicros(long d) { return d; } |
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public long toMillis(long d) { return d/(C2/C1); } |
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public long toSeconds(long d) { return d/(C3/C1); } |
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public long toMinutes(long d) { return d/(C4/C1); } |
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public long toHours(long d) { return d/(C5/C1); } |
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public long toDays(long d) { return d/(C6/C1); } |
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public long convert(long d, TimeUnit u) { return u.toMicros(d); } |
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int excessNanos(long d, long m) { return (int)((d*C1) - (m*C2)); } |
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}, |
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MILLISECONDS (2) { |
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public long toNanos(long d) { return x(d, C2/C0, MAX/(C2/C0)); } |
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public long toMicros(long d) { return x(d, C2/C1, MAX/(C2/C1)); } |
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public long toMillis(long d) { return d; } |
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public long toSeconds(long d) { return d/(C3/C2); } |
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public long toMinutes(long d) { return d/(C4/C2); } |
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public long toHours(long d) { return d/(C5/C2); } |
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public long toDays(long d) { return d/(C6/C2); } |
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public long convert(long d, TimeUnit u) { return u.toMillis(d); } |
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int excessNanos(long d, long m) { return 0; } |
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}, |
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SECONDS (3) { |
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public long toNanos(long d) { return x(d, C3/C0, MAX/(C3/C0)); } |
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public long toMicros(long d) { return x(d, C3/C1, MAX/(C3/C1)); } |
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public long toMillis(long d) { return x(d, C3/C2, MAX/(C3/C2)); } |
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public long toSeconds(long d) { return d; } |
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public long toMinutes(long d) { return d/(C4/C3); } |
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public long toHours(long d) { return d/(C5/C3); } |
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public long toDays(long d) { return d/(C6/C3); } |
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public long convert(long d, TimeUnit u) { return u.toSeconds(d); } |
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int excessNanos(long d, long m) { return 0; } |
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}, |
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MINUTES (4) { |
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public long toNanos(long d) { return x(d, C4/C0, MAX/(C4/C0)); } |
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public long toMicros(long d) { return x(d, C4/C1, MAX/(C4/C1)); } |
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public long toMillis(long d) { return x(d, C4/C2, MAX/(C4/C2)); } |
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public long toSeconds(long d) { return x(d, C4/C3, MAX/(C4/C3)); } |
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public long toMinutes(long d) { return d; } |
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public long toHours(long d) { return d/(C5/C4); } |
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public long toDays(long d) { return d/(C6/C4); } |
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public long convert(long d, TimeUnit u) { return u.toMinutes(d); } |
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int excessNanos(long d, long m) { return 0; } |
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}, |
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HOURS (5) { |
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public long toNanos(long d) { return x(d, C5/C0, MAX/(C5/C0)); } |
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public long toMicros(long d) { return x(d, C5/C1, MAX/(C5/C1)); } |
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public long toMillis(long d) { return x(d, C5/C2, MAX/(C5/C2)); } |
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public long toSeconds(long d) { return x(d, C5/C3, MAX/(C5/C3)); } |
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public long toMinutes(long d) { return x(d, C5/C4, MAX/(C5/C4)); } |
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public long toHours(long d) { return d; } |
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public long toDays(long d) { return d/(C6/C5); } |
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public long convert(long d, TimeUnit u) { return u.toHours(d); } |
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int excessNanos(long d, long m) { return 0; } |
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}, |
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DAYS (6) { |
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public long toNanos(long d) { return x(d, C6/C0, MAX/(C6/C0)); } |
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public long toMicros(long d) { return x(d, C6/C1, MAX/(C6/C1)); } |
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public long toMillis(long d) { return x(d, C6/C2, MAX/(C6/C2)); } |
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public long toSeconds(long d) { return x(d, C6/C3, MAX/(C6/C3)); } |
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public long toMinutes(long d) { return x(d, C6/C4, MAX/(C6/C4)); } |
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public long toHours(long d) { return x(d, C6/C5, MAX/(C6/C5)); } |
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public long toDays(long d) { return d; } |
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public long convert(long d, TimeUnit u) { return u.toDays(d); } |
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int excessNanos(long d, long m) { return 0; } |
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}; |
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|
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/** |
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* The index of this unit. This value is no longer used in this |
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* version of this class, but is retained for serialization |
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* compatibility with previous version. |
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*/ |
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private final int index; |
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|
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/** Internal constructor */ |
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TimeUnit(int index) { |
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this.index = index; |
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} |
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|
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// Handy constants for conversion methods |
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static final long C0 = 1L; |
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static final long C1 = C0 * 1000L; |
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static final long C2 = C1 * 1000L; |
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static final long C3 = C2 * 1000L; |
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static final long C4 = C3 * 60L; |
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static final long C5 = C4 * 60L; |
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static final long C6 = C5 * 24L; |
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|
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static final long MAX = Long.MAX_VALUE; |
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|
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/** |
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* Scale d by m, checking for overflow. |
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* This has a short name to make above code more readable. |
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*/ |
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static long x(long d, long m, long over) { |
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if (d > over) return Long.MAX_VALUE; |
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if (d < -over) return Long.MIN_VALUE; |
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return d * m; |
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} |
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|
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/** |
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* Convert the given time duration in the given unit to the |
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* current unit. Conversions from finer to coarser granulaties |
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* Convert the given time duration in the given unit to this |
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* unit. Conversions from finer to coarser granularities |
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* truncate, so lose precision. For example converting |
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* <tt>999</tt> milliseconds to seconds results in |
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* <tt>0</tt>. Conversions from coarser to finer granularities |
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* |
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* @param duration the time duration in the given <tt>unit</tt> |
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* @param unit the unit of the <tt>duration</tt> argument |
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* @return the converted duration in the current unit, |
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* @return the converted duration in this unit, |
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* or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
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* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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*/ |
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public long convert(long duration, TimeUnit unit) { |
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return doConvert(unit.index - index, duration); |
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} |
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public abstract long convert(long duration, TimeUnit unit); |
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|
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/** |
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* Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>. |
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* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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* @see #convert |
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*/ |
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public long toNanos(long duration) { |
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return doConvert(index, duration); |
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} |
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public abstract long toNanos(long duration); |
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|
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/** |
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* Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>. |
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* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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* @see #convert |
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*/ |
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public long toMicros(long duration) { |
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return doConvert(index - US, duration); |
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} |
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public abstract long toMicros(long duration); |
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|
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/** |
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* Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>. |
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* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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* @see #convert |
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*/ |
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public long toMillis(long duration) { |
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return doConvert(index - MS, duration); |
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} |
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public abstract long toMillis(long duration); |
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|
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/** |
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* Equivalent to <tt>SECONDS.convert(duration, this)</tt>. |
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* @param duration the duration |
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* @return the converted duration. |
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> |
* @return the converted duration, |
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* or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
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* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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* @see #convert |
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*/ |
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< |
public long toSeconds(long duration) { |
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< |
return doConvert(index - S, duration); |
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} |
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> |
public abstract long toSeconds(long duration); |
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> |
|
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> |
/** |
| 213 |
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* Equivalent to <tt>MINUTES.convert(duration, this)</tt>. |
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> |
* @param duration the duration |
| 215 |
> |
* @return the converted duration, |
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> |
* or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
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> |
* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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> |
* @see #convert |
| 219 |
> |
*/ |
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> |
public abstract long toMinutes(long duration); |
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> |
|
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> |
/** |
| 223 |
> |
* Equivalent to <tt>HOURS.convert(duration, this)</tt>. |
| 224 |
> |
* @param duration the duration |
| 225 |
> |
* @return the converted duration, |
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> |
* or <tt>Long.MIN_VALUE</tt> if conversion would negatively |
| 227 |
> |
* overflow, or <tt>Long.MAX_VALUE</tt> if it would positively overflow. |
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> |
* @see #convert |
| 229 |
> |
*/ |
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> |
public abstract long toHours(long duration); |
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|
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/** |
| 233 |
< |
* Perform a timed <tt>Object.wait</tt> using the current time unit. |
| 234 |
< |
* This is a convenience method that converts timeout arguments into the |
| 235 |
< |
* form required by the <tt>Object.wait</tt> method. |
| 236 |
< |
* <p>For example, you could implement a blocking <tt>poll</tt> method (see |
| 237 |
< |
* {@link BlockingQueue#poll BlockingQueue.poll} using: |
| 233 |
> |
* Equivalent to <tt>DAYS.convert(duration, this)</tt>. |
| 234 |
> |
* @param duration the duration |
| 235 |
> |
* @return the converted duration |
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> |
* @see #convert |
| 237 |
> |
*/ |
| 238 |
> |
public abstract long toDays(long duration); |
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> |
|
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> |
/** |
| 241 |
> |
* Utility to compute the excess-nanosecond argument to wait, |
| 242 |
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* sleep, join. |
| 243 |
> |
* @param d the duration |
| 244 |
> |
* @param m the number of milliseconds |
| 245 |
> |
* @return the number of nanoseconds |
| 246 |
> |
*/ |
| 247 |
> |
abstract int excessNanos(long d, long m); |
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> |
|
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> |
/** |
| 250 |
> |
* Performs a timed <tt>Object.wait</tt> using this time unit. |
| 251 |
> |
* This is a convenience method that converts timeout arguments |
| 252 |
> |
* into the form required by the <tt>Object.wait</tt> method. |
| 253 |
> |
* |
| 254 |
> |
* <p>For example, you could implement a blocking <tt>poll</tt> |
| 255 |
> |
* method (see {@link BlockingQueue#poll BlockingQueue.poll}) |
| 256 |
> |
* using: |
| 257 |
> |
* |
| 258 |
|
* <pre> public synchronized Object poll(long timeout, TimeUnit unit) throws InterruptedException { |
| 259 |
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* while (empty) { |
| 260 |
|
* unit.timedWait(this, timeout); |
| 261 |
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* ... |
| 262 |
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* } |
| 263 |
|
* }</pre> |
| 264 |
+ |
* |
| 265 |
|
* @param obj the object to wait on |
| 266 |
< |
* @param timeout the maximum time to wait. |
| 266 |
> |
* @param timeout the maximum time to wait. If less than |
| 267 |
> |
* or equal to zero, do not wait at all. |
| 268 |
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* @throws InterruptedException if interrupted while waiting. |
| 269 |
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* @see Object#wait(long, int) |
| 270 |
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*/ |
| 271 |
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public void timedWait(Object obj, long timeout) |
| 272 |
< |
throws InterruptedException { |
| 272 |
> |
throws InterruptedException { |
| 273 |
|
if (timeout > 0) { |
| 274 |
< |
long ms = MILLISECONDS.convert(timeout, this); |
| 274 |
> |
long ms = toMillis(timeout); |
| 275 |
|
int ns = excessNanos(timeout, ms); |
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obj.wait(ms, ns); |
| 277 |
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} |
| 278 |
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} |
| 279 |
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|
| 280 |
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/** |
| 281 |
< |
* Perform a timed <tt>Thread.join</tt> using the current time unit. |
| 281 |
> |
* Performs a timed <tt>Thread.join</tt> using this time unit. |
| 282 |
|
* This is a convenience method that converts time arguments into the |
| 283 |
|
* form required by the <tt>Thread.join</tt> method. |
| 284 |
|
* @param thread the thread to wait for |
| 285 |
< |
* @param timeout the maximum time to wait |
| 285 |
> |
* @param timeout the maximum time to wait. If less than |
| 286 |
> |
* or equal to zero, do not wait at all. |
| 287 |
|
* @throws InterruptedException if interrupted while waiting. |
| 288 |
|
* @see Thread#join(long, int) |
| 289 |
|
*/ |
| 290 |
|
public void timedJoin(Thread thread, long timeout) |
| 291 |
< |
throws InterruptedException { |
| 291 |
> |
throws InterruptedException { |
| 292 |
|
if (timeout > 0) { |
| 293 |
< |
long ms = MILLISECONDS.convert(timeout, this); |
| 293 |
> |
long ms = toMillis(timeout); |
| 294 |
|
int ns = excessNanos(timeout, ms); |
| 295 |
|
thread.join(ms, ns); |
| 296 |
|
} |
| 297 |
|
} |
| 298 |
|
|
| 299 |
|
/** |
| 300 |
< |
* Perform a <tt>Thread.sleep</tt> using the current time unit. |
| 300 |
> |
* Performs a <tt>Thread.sleep</tt> using this unit. |
| 301 |
|
* This is a convenience method that converts time arguments into the |
| 302 |
|
* form required by the <tt>Thread.sleep</tt> method. |
| 303 |
< |
* @param timeout the minimum time to sleep |
| 303 |
> |
* @param timeout the minimum time to sleep. If less than |
| 304 |
> |
* or equal to zero, do not sleep at all. |
| 305 |
|
* @throws InterruptedException if interrupted while sleeping. |
| 306 |
|
* @see Thread#sleep |
| 307 |
|
*/ |
| 308 |
|
public void sleep(long timeout) throws InterruptedException { |
| 309 |
|
if (timeout > 0) { |
| 310 |
< |
long ms = MILLISECONDS.convert(timeout, this); |
| 310 |
> |
long ms = toMillis(timeout); |
| 311 |
|
int ns = excessNanos(timeout, ms); |
| 312 |
|
Thread.sleep(ms, ns); |
| 313 |
|
} |
| 314 |
|
} |
| 315 |
|
|
| 190 |
– |
/** |
| 191 |
– |
* Return the common name for this unit. |
| 192 |
– |
*/ |
| 193 |
– |
public String toString() { |
| 194 |
– |
return unitName; |
| 195 |
– |
} |
| 196 |
– |
|
| 197 |
– |
|
| 198 |
– |
/** |
| 199 |
– |
* Returns true if the given object is a TimeUnit representing |
| 200 |
– |
* the same unit as this TimeUnit. |
| 201 |
– |
* @param x the object to compare |
| 202 |
– |
* @return true if equal |
| 203 |
– |
*/ |
| 204 |
– |
public boolean equals(Object x) { |
| 205 |
– |
if (!(x instanceof TimeUnit)) |
| 206 |
– |
return false; |
| 207 |
– |
return ((TimeUnit)x).index == index; |
| 208 |
– |
} |
| 209 |
– |
|
| 210 |
– |
/** |
| 211 |
– |
* Returns a hash code for this TimeUnit. |
| 212 |
– |
* @return the hash code |
| 213 |
– |
*/ |
| 214 |
– |
public int hashCode() { |
| 215 |
– |
return unitName.hashCode(); |
| 216 |
– |
} |
| 217 |
– |
|
| 218 |
– |
private final String unitName; |
| 219 |
– |
|
| 220 |
– |
/* ordered indices for each time unit */ |
| 221 |
– |
private static final int NS = 0; |
| 222 |
– |
private static final int US = 1; |
| 223 |
– |
private static final int MS = 2; |
| 224 |
– |
private static final int S = 3; |
| 225 |
– |
|
| 226 |
– |
/** quick lookup table for conversion factors */ |
| 227 |
– |
static final int[] multipliers = { 1, |
| 228 |
– |
1000, |
| 229 |
– |
1000*1000, |
| 230 |
– |
1000*1000*1000 }; |
| 231 |
– |
|
| 232 |
– |
/** lookup table to check saturation */ |
| 233 |
– |
static final long[] overflows = { |
| 234 |
– |
// Note that because we are dividing these down anyway, |
| 235 |
– |
// we don't have to deal with asymmetry of MIN/MAX values. |
| 236 |
– |
0, // unused |
| 237 |
– |
Long.MAX_VALUE / 1000, |
| 238 |
– |
Long.MAX_VALUE / (1000 * 1000), |
| 239 |
– |
Long.MAX_VALUE / (1000 * 1000 * 1000) }; |
| 240 |
– |
|
| 241 |
– |
/** the index of this unit */ |
| 242 |
– |
int index; |
| 243 |
– |
|
| 244 |
– |
/** private constructor */ |
| 245 |
– |
TimeUnit(int index, String name) { |
| 246 |
– |
this.index = index; |
| 247 |
– |
this.unitName = name; |
| 248 |
– |
} |
| 249 |
– |
|
| 250 |
– |
/** |
| 251 |
– |
* Utility method to compute the excess-nanosecond argument to |
| 252 |
– |
* wait, sleep, join. The results may overflow, so public methods |
| 253 |
– |
* invoking this should document possible overflow unless |
| 254 |
– |
* overflow is known not to be possible for the given arguments. |
| 255 |
– |
*/ |
| 256 |
– |
private int excessNanos(long time, long ms) { |
| 257 |
– |
if (index == NS) |
| 258 |
– |
return (int) (time - (ms * multipliers[MS-NS])); |
| 259 |
– |
else if (index == US) |
| 260 |
– |
return (int) ((time * multipliers[US-NS]) - (ms * multipliers[MS-NS])); |
| 261 |
– |
else |
| 262 |
– |
return 0; |
| 263 |
– |
} |
| 264 |
– |
|
| 265 |
– |
/** Unit for one-second granularities. */ |
| 266 |
– |
public static final TimeUnit SECONDS = new TimeUnit(S, "seconds"); |
| 267 |
– |
|
| 268 |
– |
/** Unit for one-millisecond granularities. */ |
| 269 |
– |
public static final TimeUnit MILLISECONDS = new TimeUnit(MS, "milliseconds"); |
| 270 |
– |
|
| 271 |
– |
/** Unit for one-microsecond granularities. */ |
| 272 |
– |
public static final TimeUnit MICROSECONDS = new TimeUnit(US, "microseconds"); |
| 273 |
– |
|
| 274 |
– |
/** Unit for one-nanosecond granularities. */ |
| 275 |
– |
public static final TimeUnit NANOSECONDS = new TimeUnit(NS, "nanoseconds"); |
| 276 |
– |
|
| 316 |
|
} |
