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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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|
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package java.util.concurrent; |
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|
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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. 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>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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* <pre> Lock lock = ...; |
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* if ( lock.tryLock(50L, TimeUnit.MILLISECONDS) ) ... |
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* </pre> |
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* while this code will timeout in 50 seconds: |
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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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* |
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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 enum TimeUnit { |
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NANOSECONDS { |
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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 { |
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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 { |
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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 { |
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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 { |
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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 { |
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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 { |
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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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// 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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// To maintain full signature compatibility with 1.5, and to improve the |
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// clarity of the generated javadoc (see 6287639: Abstract methods in |
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// enum classes should not be listed as abstract), method convert |
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// etc. are not declared abstract but otherwise act as abstract methods. |
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|
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/** |
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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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* with arguments that would numerically overflow saturate to |
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* <tt>Long.MIN_VALUE</tt> if negative or <tt>Long.MAX_VALUE</tt> |
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* if positive. |
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* |
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* <p>For example, to convert 10 minutes to milliseconds, use: |
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* <tt>TimeUnit.MILLISECONDS.convert(10L, TimeUnit.MINUTES)</tt> |
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* |
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* @param sourceDuration the time duration in the given <tt>sourceUnit</tt> |
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* @param sourceUnit the unit of the <tt>sourceDuration</tt> argument |
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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 sourceDuration, TimeUnit sourceUnit) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>NANOSECONDS.convert(duration, this)</tt>. |
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* @param duration the 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 toNanos(long duration) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>MICROSECONDS.convert(duration, this)</tt>. |
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* @param duration the 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 toMicros(long duration) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>MILLISECONDS.convert(duration, this)</tt>. |
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* @param duration the 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 toMillis(long duration) { |
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throw new AbstractMethodError(); |
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} |
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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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* 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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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>MINUTES.convert(duration, this)</tt>. |
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* @param duration the 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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* @since 1.6 |
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*/ |
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public long toMinutes(long duration) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>HOURS.convert(duration, this)</tt>. |
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* @param duration the 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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* @since 1.6 |
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*/ |
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public long toHours(long duration) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Equivalent to <tt>DAYS.convert(duration, this)</tt>. |
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* @param duration the duration |
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* @return the converted duration |
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* @see #convert |
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* @since 1.6 |
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*/ |
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public long toDays(long duration) { |
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throw new AbstractMethodError(); |
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} |
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|
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/** |
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* Utility to compute the excess-nanosecond argument to wait, |
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* sleep, join. |
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* @param d the duration |
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* @param m the number of milliseconds |
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* @return the number of nanoseconds |
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*/ |
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abstract int excessNanos(long d, long m); |
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|
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/** |
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* Performs a timed <tt>Object.wait</tt> using this time unit. |
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* This is a convenience method that converts timeout arguments |
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* into the form required by the <tt>Object.wait</tt> method. |
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* |
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* <p>For example, you could implement a blocking <tt>poll</tt> |
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* method (see {@link BlockingQueue#poll BlockingQueue.poll}) |
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* using: |
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* |
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* <pre> public synchronized Object poll(long timeout, TimeUnit unit) throws InterruptedException { |
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* while (empty) { |
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* unit.timedWait(this, timeout); |
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* ... |
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* } |
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* }</pre> |
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* |
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* @param obj the object to wait on |
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* @param timeout the maximum time to wait. If less than |
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* or equal to zero, do not wait at all. |
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* @throws InterruptedException if interrupted while waiting. |
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* @see Object#wait(long, int) |
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*/ |
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public void timedWait(Object obj, long timeout) |
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throws InterruptedException { |
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if (timeout > 0) { |
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long ms = toMillis(timeout); |
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int ns = excessNanos(timeout, ms); |
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obj.wait(ms, ns); |
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} |
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} |
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|
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/** |
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* Performs a timed <tt>Thread.join</tt> using this time unit. |
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* This is a convenience method that converts time arguments into the |
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* form required by the <tt>Thread.join</tt> method. |
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* @param thread the thread to wait for |
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* @param timeout the maximum time to wait. If less than |
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* or equal to zero, do not wait at all. |
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* @throws InterruptedException if interrupted while waiting. |
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* @see Thread#join(long, int) |
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*/ |
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public void timedJoin(Thread thread, long timeout) |
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throws InterruptedException { |
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if (timeout > 0) { |
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long ms = toMillis(timeout); |
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int ns = excessNanos(timeout, ms); |
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thread.join(ms, ns); |
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} |
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} |
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|
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/** |
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* Performs a <tt>Thread.sleep</tt> using this unit. |
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* This is a convenience method that converts time arguments into the |
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* form required by the <tt>Thread.sleep</tt> method. |
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* @param timeout the minimum time to sleep. If less than |
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* or equal to zero, do not sleep at all. |
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* @throws InterruptedException if interrupted while sleeping. |
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* @see Thread#sleep |
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*/ |
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public void sleep(long timeout) throws InterruptedException { |
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if (timeout > 0) { |
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long ms = toMillis(timeout); |
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int ns = excessNanos(timeout, ms); |
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Thread.sleep(ms, ns); |
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} |
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} |
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|
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} |
