java.util.concurrent
Class TimeUnit

java.lang.Object
  extended by java.util.concurrent.TimeUnit
All Implemented Interfaces:
Serializable
public final class TimeUnit
extends Object
implements Serializable

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. TimeUnit is a "featherweight" class. It does not maintain time information, but only helps organize and use time representations that may be maintained separately across various contexts.

This class cannot be directly instantiated. Use the SECONDS, MILLISECONDS, MICROSECONDS, and NANOSECONDS static instances that provide predefined units of precision. If you use these frequently, consider statically importing this class.

A TimeUnit is mainly used to inform blocking methods which can timeout, how the timeout 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
See Also:
Serialized Form

Field Summary
static TimeUnit MICROSECONDS
          Unit for one-microsecond granularities.
static TimeUnit MILLISECONDS
          Unit for one-millisecond granularities.
static TimeUnit NANOSECONDS
          Unit for one-nanosecond granularities.
static TimeUnit SECONDS
          Unit for one-second granularities.
 
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).
 String toString()
          Return the common name for this unit.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

SECONDS

public static final TimeUnit SECONDS
Unit for one-second granularities.

MILLISECONDS

public static final TimeUnit MILLISECONDS
Unit for one-millisecond granularities.

MICROSECONDS

public static final TimeUnit MICROSECONDS
Unit for one-microsecond granularities.

NANOSECONDS

public static final TimeUnit NANOSECONDS
Unit for one-nanosecond granularities.

Method Detail

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)

toString

public String toString()
Return the common name for this unit.

Overrides:
toString in class Object
Returns:
a string representation of the object.