TimeUnit (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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Java^TM 2 Platform
Standard Ed. 5.0

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java.util.concurrent
Enum TimeUnit

java.lang.Object
  java.lang.Enum<TimeUnit>
      java.util.concurrent.TimeUnit

All Implemented Interfaces:: Serializable, Comparable<TimeUnit>

public enum TimeUnit
extends Enum<TimeUnit>
extends Enum<TimeUnit>

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 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 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

Enum Constant Summary

MICROSECONDS


MILLISECONDS


NANOSECONDS


SECONDS


Method Summary

long convert(long duration, TimeUnit unit)
          Convert the given time duration in the given unit to this unit.

void sleep(long timeout)
          Perform a Thread.sleep using this unit.

void timedJoin(Thread thread, long timeout)
          Perform a timed Thread.join using this time unit.

void timedWait(Object obj, long timeout)
          Perform a timed Object.wait using this time unit.

long toMicros(long duration)
          Equivalent to MICROSECONDS.convert(duration, this).

long toMillis(long duration)
          Equivalent to MILLISECONDS.convert(duration, this).

long toNanos(long duration)
          Equivalent to NANOSECONDS.convert(duration, this).

long toSeconds(long duration)
          Equivalent to SECONDS.convert(duration, this).

static TimeUnit valueOf(String name)
          Returns the enum constant of this type with the specified name.

static TimeUnit[] values()
          Returns an array containing the constants of this enum type, in the order they're declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Enum Constant Summary
`MICROSECONDS`
`MILLISECONDS`
`NANOSECONDS`
`SECONDS`

Method Summary
`long`	`convert(long duration, TimeUnit unit)` Convert the given time duration in the given unit to this unit.
`void`	`sleep(long timeout)` Perform a `Thread.sleep` using this unit.
`void`	`timedJoin(Thread thread, long timeout)` Perform a timed `Thread.join` using this time unit.
`void`	`timedWait(Object obj, long timeout)` Perform a timed `Object.wait` using this time unit.
`long`	`toMicros(long duration)` Equivalent to `MICROSECONDS.convert(duration, this)`.
`long`	`toMillis(long duration)` Equivalent to `MILLISECONDS.convert(duration, this)`.
`long`	`toNanos(long duration)` Equivalent to `NANOSECONDS.convert(duration, this)`.
`long`	`toSeconds(long duration)` Equivalent to `SECONDS.convert(duration, this)`.
`static TimeUnit`	`valueOf(String name)` Returns the enum constant of this type with the specified name.
`static TimeUnit[]`	`values()` Returns an array containing the constants of this enum type, in the order they're declared.

Methods inherited from class java.lang.Enum
`clone, compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf`

Methods inherited from class java.lang.Object
`finalize, getClass, notify, notifyAll, wait, wait, wait`

Enum Constant Detail

NANOSECONDS

public static final TimeUnit NANOSECONDS

MICROSECONDS

public static final TimeUnit MICROSECONDS

MILLISECONDS

public static final TimeUnit MILLISECONDS

SECONDS

public static final TimeUnit SECONDS

Method Detail

values

public static final TimeUnit[] values()

Returns an array containing the constants of this enum type, in the order they're declared. This method may be used to iterate over the constants as follows:

for(TimeUnit c : TimeUnit.values())
        System.out.println(c);

Returns:: an array containing the constants of this enum type, in the order they're declared

valueOf

public static TimeUnit valueOf(String name)

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.)

Parameters:: name - the name of the enum constant to be returned.
Returns:: the enum constant with the specified name
Throws:: IllegalArgumentException - if this enum type has no constant with the specified name

convert

public long convert(long duration,
                    TimeUnit unit)

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.

Parameters:: duration - the time duration in the given unit; unit - the unit of the duration argument
Returns:: the converted duration in this unit, or Long.MIN_VALUE if conversion would negatively overflow, or Long.MAX_VALUE if it would positively overflow.

toNanos

public long toNanos(long duration)

Equivalent to NANOSECONDS.convert(duration, this).

Parameters:: duration - the duration
Returns:: the converted duration, or Long.MIN_VALUE if conversion would negatively overflow, or Long.MAX_VALUE if it would positively overflow.
See Also:: convert(long, java.util.concurrent.TimeUnit)

toMicros

public long toMicros(long duration)

Equivalent to MICROSECONDS.convert(duration, this).

Parameters:: duration - the duration
Returns:: the converted duration, or Long.MIN_VALUE if conversion would negatively overflow, or Long.MAX_VALUE if it would positively overflow.
See Also:: convert(long, java.util.concurrent.TimeUnit)

toMillis

public long toMillis(long duration)

Equivalent to MILLISECONDS.convert(duration, this).

Parameters:: duration - the duration
Returns:: the converted duration, or Long.MIN_VALUE if conversion would negatively overflow, or Long.MAX_VALUE if it would positively overflow.
See Also:: convert(long, java.util.concurrent.TimeUnit)

toSeconds

public long toSeconds(long duration)

Equivalent to SECONDS.convert(duration, this).

Parameters:: duration - the duration
Returns:: the converted duration.
See Also:: convert(long, java.util.concurrent.TimeUnit)

timedWait

public void timedWait(Object obj,
                      long timeout)
               throws InterruptedException

Perform 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 BlockingQueue.poll) using:

  public synchronized  Object poll(long timeout, TimeUnit unit) throws InterruptedException {
    while (empty) {
      unit.timedWait(this, timeout);
      ...
    }
  }

Parameters:: obj - the object to wait on; timeout - the maximum time to wait.
Throws:: InterruptedException - if interrupted while waiting.
See Also:: Object.wait(long, int)

timedJoin

public void timedJoin(Thread thread,
                      long timeout)
               throws InterruptedException

Perform 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.

Parameters:: thread - the thread to wait for; timeout - the maximum time to wait
Throws:: InterruptedException - if interrupted while waiting.
See Also:: Thread.join(long, int)

sleep

public void sleep(long timeout)
           throws InterruptedException

Perform a Thread.sleep using this unit. This is a convenience method that converts time arguments into the form required by the Thread.sleep method.

Parameters:: timeout - the minimum time to sleep
Throws:: InterruptedException - if interrupted while sleeping.
See Also:: Thread.sleep(long)