All Downloads are FREE. Search and download functionalities are using the official Maven repository.

scala.actors.threadpool.TimeUnit Maven / Gradle / Ivy

There is a newer version: 2.11.12
Show newest version
/*
 * 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/licenses/publicdomain
 */

package scala.actors.threadpool;

import java.io.InvalidObjectException;
import java.io.ObjectStreamException;

/**
  * A 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
  * 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.
  *
  * 

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 * edu.emory.mathcs.backport.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 abstract class TimeUnit implements java.io.Serializable { public static final TimeUnit NANOSECONDS = new TimeUnit(0, "NANOSECONDS") { private final static long serialVersionUID = 535148490883208361L; 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)); } }; public static final TimeUnit MICROSECONDS = new TimeUnit(1, "MICROSECONDS") { private final static long serialVersionUID = 2185906575929579108L; 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)); } }; public static final TimeUnit MILLISECONDS = new TimeUnit(2, "MILLISECONDS") { private final static long serialVersionUID = 9032047794123325184L; 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; } }; public static final TimeUnit SECONDS = new TimeUnit(3, "SECONDS") { private final static long serialVersionUID = 227755028449378390L; 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; } }; public static final TimeUnit MINUTES = new TimeUnit(4, "MINUTES") { private final static long serialVersionUID = 1827351566402609187L; 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; } }; public static final TimeUnit HOURS = new TimeUnit(5, "HOURS") { private final static long serialVersionUID = -6438436134732089810L; 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; } }; public static final TimeUnit DAYS = new TimeUnit(6, "DAYS") { private final static long serialVersionUID = 567463171959674600L; 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; } }; private static final TimeUnit[] values = new TimeUnit[] { NANOSECONDS, MICROSECONDS, MILLISECONDS, SECONDS, MINUTES, HOURS, DAYS }; public static TimeUnit[] values() { return (TimeUnit[])values.clone(); } /** * Returns the enum constant of this type with the specified name. The * string must match exactly an identifier used to declare an * enum constant in this type. (Extraneous whitespace characters are not * permitted.) * * @param name the name of the enum constant to be returned * @return the enum constant with the specified name * @throws IllegalArgumentException * if this enum type has no constant with the specified name */ public static TimeUnit valueOf(String name) { for (int i = 0; i < values.length; i++) { if (values[i].name.equals(name)) { return values[i]; } } throw new IllegalArgumentException("No enum const TimeUnit." + name); } /** * The ordinal of this unit. This is useful both for {@link #ordinal()} * and to maintain serialization consistence with earlier versions. */ private final int index; /** name of this unit */ private final String name; /** Internal constructor */ TimeUnit(int index, String name) { this.index = index; this.name = name; } // Handy constants for conversion methods static final long C0 = 1; static final long C1 = C0 * 1000; static final long C2 = C1 * 1000; static final long C3 = C2 * 1000; static final long C4 = C3 * 60; static final long C5 = C4 * 60; static final long C6 = C5 * 24; 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; } /** * 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 abstract long convert(long sourceDuration, TimeUnit sourceUnit); /** * 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 abstract long toNanos(long duration); /** * 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 abstract long toMicros(long duration); /** * 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 abstract long toMillis(long duration); /** * 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 abstract long toSeconds(long duration); /** * 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 abstract long toMinutes(long duration); /** * 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 abstract long toHours(long duration); /** * Equivalent to DAYS.convert(duration, this). * @param duration the duration * @return the converted duration * @see #convert * @since 1.6 */ public abstract long toDays(long duration); /** * 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); /** * Returns the name of this enum constant, exactly as declared in its enum * declaration. Most programmers should use the * {@link #toString()} method in preference to this one, as the toString * method may return a more user-friendly name. This method is * designed primarily for use in specialized situations where correctness * depends on getting the exact name, which will not vary from release to * release. * * @return the name of this enum constant */ public String name() { return name; } /** * Returns the ordinal of this enumeration constant (its position in its * enum declaration, where the initial constant is assigned an ordinal of * zero). Most programmers will have no use for this method. It is * designed for use by sophisticated enum-based data structures, such as * EnumSet and EnumMap. * * @return the ordinal of this enumeration constant */ public int ordinal() { return index; } /* * Guarantees that deserialized objects will be referentially equal to the * standard enumeration objects. */ protected Object readResolve() throws ObjectStreamException { try { return valueOf(name); } catch (IllegalArgumentException e) { throw new InvalidObjectException(name + " is not a valid enum for TimeUnit"); } } /** * Performs a timed 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: * *

  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. * @see java.lang.Object#wait(long, int) */ 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 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. * @see java.lang.Thread#join(long, int) */ 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 Thread.sleep using this unit. * This is a convenience method that converts time arguments into the * form required by the Thread.sleep method. * @param timeout the maximum time to sleep. If less than * or equal to zero, do not sleep at all. * @throws InterruptedException if interrupted while sleeping. * @see java.lang.Thread#sleep */ public void sleep(long timeout) throws InterruptedException { if (timeout > 0) { long ms = toMillis(timeout); int ns = excessNanos(timeout, ms); Thread.sleep(ms, ns); } } public String toString() { return name; } }




© 2015 - 2024 Weber Informatics LLC | Privacy Policy