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TimeUnit (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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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>

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public 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 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 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

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Enum Constant Summary
DAYS
HOURS
MICROSECONDS
MILLISECONDS
MINUTES
NANOSECONDS
SECONDS

 

Method Summary
long	convert(long sourceDuration, TimeUnit sourceUnit)           Convert the given time duration in the given unit to this unit.
void	sleep(long timeout)           Performs a Thread.sleep using this unit.
void	timedJoin(Thread thread, long timeout)           Performs a timed Thread.join using this time unit.
void	timedWait(Object obj, long timeout)           Performs a timed Object.wait using this time unit.
long	toDays(long duration)           Equivalent to DAYS.convert(duration, this).
long	toHours(long duration)           Equivalent to HOURS.convert(duration, this).
long	toMicros(long duration)           Equivalent to MICROSECONDS.convert(duration, this).
long	toMillis(long duration)           Equivalent to MILLISECONDS.convert(duration, this).
long	toMinutes(long duration)           Equivalent to MINUTES.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 are declared.

 

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

 

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

 

Enum Constant Detail

NANOSECONDS

public static final TimeUnit NANOSECONDS

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MICROSECONDS

public static final TimeUnit MICROSECONDS

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MILLISECONDS

public static final TimeUnit MILLISECONDS

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SECONDS

public static final TimeUnit SECONDS

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MINUTES

public static final TimeUnit MINUTES

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HOURS

public static final TimeUnit HOURS

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DAYS

public static final TimeUnit DAYS

Method Detail

values

public static TimeUnit[] values()

Returns an array containing the constants of this enum type, in the order they are 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 are declared

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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

NullPointerException - if the argument is null

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convert

public long convert(long sourceDuration,
                    TimeUnit sourceUnit)

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)

Parameters:

sourceDuration - the time duration in the given sourceUnit

sourceUnit - the unit of the sourceDuration 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.

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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)

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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)

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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)

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toSeconds

public long toSeconds(long duration)

Equivalent to SECONDS.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)

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toMinutes

public long toMinutes(long duration)

Equivalent to MINUTES.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.

Since:

1.6

See Also:

convert(long, java.util.concurrent.TimeUnit)

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toHours

public long toHours(long duration)

Equivalent to HOURS.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.

Since:

1.6

See Also:

convert(long, java.util.concurrent.TimeUnit)

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toDays

public long toDays(long duration)

Equivalent to DAYS.convert(duration, this).

Parameters:

duration - the duration

Returns:

the converted duration

Since:

1.6

See Also:

convert(long, java.util.concurrent.TimeUnit)

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timedWait

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

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 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. If less than or equal to zero, do not wait at all.

Throws:

InterruptedException - if interrupted while waiting.

See Also:

Object.wait(long, int)

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timedJoin

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

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.

Parameters:

thread - the thread to wait for

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 Also:

Thread.join(long, int)

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sleep

public void sleep(long timeout)
           throws InterruptedException

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.

Parameters:

timeout - the minimum time to sleep. If less than or equal to zero, do not sleep at all.

Throws:

InterruptedException - if interrupted while sleeping.

See Also:

Thread.sleep(long)

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