java.util.concurrent.locks

Class AbstractQueuedSynchronizer.ConditionObject

java.lang.Object

java.util.concurrent.locks.AbstractQueuedSynchronizer.ConditionObject

All Implemented Interfaces:

Serializable, Condition

Enclosing class:

AbstractQueuedSynchronizer

public class AbstractQueuedSynchronizer.ConditionObject
extends Object
implements Condition, Serializable

Condition implementation for a AbstractQueuedSynchronizer serving as the basis of a Lock implementation.

Method documentation for this class describes mechanics, not behavioral specifications from the point of view of Lock and Condition users. Exported versions of this class will in general need to be accompanied by documentation describing condition semantics that rely on those of the associated AbstractQueuedSynchronizer.

This class is Serializable, but all fields are transient, so deserialized conditions have no waiters.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ConditionObject() Creates a new ConditionObject instance.

Method Summary

Modifier and Type	Method and Description
void	await() Implements interruptible condition wait.
boolean	await(long time, TimeUnit unit) Implements timed condition wait.
long	awaitNanos(long nanosTimeout) Implements timed condition wait.
void	awaitUninterruptibly() Implements uninterruptible condition wait.
boolean	awaitUntil(Date deadline) Implements absolute timed condition wait.
protected Collection<Thread>	getWaitingThreads() Returns a collection containing those threads that may be waiting on this Condition.
protected int	getWaitQueueLength() Returns an estimate of the number of threads waiting on this condition.
protected boolean	hasWaiters() Queries whether any threads are waiting on this condition.
void	signal() Moves the longest-waiting thread, if one exists, from the wait queue for this condition to the wait queue for the owning lock.
void	signalAll() Moves all threads from the wait queue for this condition to the wait queue for the owning lock.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ConditionObject

public ConditionObject()

Creates a new ConditionObject instance.

Method Detail

signal

public final void signal()

Moves the longest-waiting thread, if one exists, from the wait queue for this condition to the wait queue for the owning lock.

Specified by:

signal in interface Condition

Throws:

IllegalMonitorStateException - if AbstractQueuedSynchronizer.isHeldExclusively() returns false

signalAll

public final void signalAll()

Moves all threads from the wait queue for this condition to the wait queue for the owning lock.

Specified by:

signalAll in interface Condition

Throws:

IllegalMonitorStateException - if AbstractQueuedSynchronizer.isHeldExclusively() returns false

awaitUninterruptibly

public final void awaitUninterruptibly()

Implements uninterruptible condition wait.

1. Save lock state returned by AbstractQueuedSynchronizer.getState().
2. Invoke AbstractQueuedSynchronizer.release(int) with saved state as argument, throwing IllegalMonitorStateException if it fails.
3. Block until signalled.
4. Reacquire by invoking specialized version of AbstractQueuedSynchronizer.acquire(int) with saved state as argument.

Specified by:

awaitUninterruptibly in interface Condition

await

public final void await()
                 throws InterruptedException

Implements interruptible condition wait.

1. If current thread is interrupted, throw InterruptedException.
2. Save lock state returned by AbstractQueuedSynchronizer.getState().
3. Invoke AbstractQueuedSynchronizer.release(int) with saved state as argument, throwing IllegalMonitorStateException if it fails.
4. Block until signalled or interrupted.
5. Reacquire by invoking specialized version of AbstractQueuedSynchronizer.acquire(int) with saved state as argument.
6. If interrupted while blocked in step 4, throw InterruptedException.

Specified by:

await in interface Condition

Throws:

InterruptedException - if the current thread is interrupted (and interruption of thread suspension is supported)

awaitNanos

public final long awaitNanos(long nanosTimeout)
                      throws InterruptedException

Implements timed condition wait.

1. If current thread is interrupted, throw InterruptedException.
2. Save lock state returned by AbstractQueuedSynchronizer.getState().
3. Invoke AbstractQueuedSynchronizer.release(int) with saved state as argument, throwing IllegalMonitorStateException if it fails.
4. Block until signalled, interrupted, or timed out.
5. Reacquire by invoking specialized version of AbstractQueuedSynchronizer.acquire(int) with saved state as argument.
6. If interrupted while blocked in step 4, throw InterruptedException.

Specified by:

awaitNanos in interface Condition

Parameters:

nanosTimeout - the maximum time to wait, in nanoseconds

Returns:

an estimate of the nanosTimeout value minus the time spent waiting upon return from this method. A positive value may be used as the argument to a subsequent call to this method to finish waiting out the desired time. A value less than or equal to zero indicates that no time remains.

Throws:

InterruptedException - if the current thread is interrupted (and interruption of thread suspension is supported)

awaitUntil

public final boolean awaitUntil(Date deadline)
                         throws InterruptedException

Implements absolute timed condition wait.

1. If current thread is interrupted, throw InterruptedException.
2. Save lock state returned by AbstractQueuedSynchronizer.getState().
3. Invoke AbstractQueuedSynchronizer.release(int) with saved state as argument, throwing IllegalMonitorStateException if it fails.
4. Block until signalled, interrupted, or timed out.
5. Reacquire by invoking specialized version of AbstractQueuedSynchronizer.acquire(int) with saved state as argument.
6. If interrupted while blocked in step 4, throw InterruptedException.
7. If timed out while blocked in step 4, return false, else true.

Specified by:

awaitUntil in interface Condition

Parameters:

deadline - the absolute time to wait until

Returns:

false if the deadline has elapsed upon return, else true

Throws:

InterruptedException - if the current thread is interrupted (and interruption of thread suspension is supported)

await

public final boolean await(long time,
                           TimeUnit unit)
                    throws InterruptedException

Implements timed condition wait.

1. If current thread is interrupted, throw InterruptedException.
2. Save lock state returned by AbstractQueuedSynchronizer.getState().
3. Invoke AbstractQueuedSynchronizer.release(int) with saved state as argument, throwing IllegalMonitorStateException if it fails.
4. Block until signalled, interrupted, or timed out.
5. Reacquire by invoking specialized version of AbstractQueuedSynchronizer.acquire(int) with saved state as argument.
6. If interrupted while blocked in step 4, throw InterruptedException.
7. If timed out while blocked in step 4, return false, else true.

Specified by:

await in interface Condition

Parameters:

time - the maximum time to wait

unit - the time unit of the time argument

Returns:

false if the waiting time detectably elapsed before return from the method, else true

Throws:

InterruptedException - if the current thread is interrupted (and interruption of thread suspension is supported)

hasWaiters

protected final boolean hasWaiters()

Queries whether any threads are waiting on this condition. Implements AbstractQueuedSynchronizer.hasWaiters(java.util.concurrent.locks.AbstractQueuedSynchronizer.ConditionObject).

Returns:

true if there are any waiting threads

Throws:

IllegalMonitorStateException - if AbstractQueuedSynchronizer.isHeldExclusively() returns false

getWaitQueueLength

protected final int getWaitQueueLength()

Returns an estimate of the number of threads waiting on this condition. Implements AbstractQueuedSynchronizer.getWaitQueueLength(java.util.concurrent.locks.AbstractQueuedSynchronizer.ConditionObject).

Returns:

the estimated number of waiting threads

Throws:

IllegalMonitorStateException - if AbstractQueuedSynchronizer.isHeldExclusively() returns false

getWaitingThreads

protected final Collection<Thread> getWaitingThreads()

Returns a collection containing those threads that may be waiting on this Condition. Implements AbstractQueuedSynchronizer.getWaitingThreads(java.util.concurrent.locks.AbstractQueuedSynchronizer.ConditionObject).

Returns:

the collection of threads

Throws:

IllegalMonitorStateException - if AbstractQueuedSynchronizer.isHeldExclusively() returns false