Class QueuedSemaphore

java.lang.Object

EDU.oswego.cs.dl.util.concurrent.Semaphore

EDU.oswego.cs.dl.util.concurrent.QueuedSemaphore

All Implemented Interfaces:

Sync

Direct Known Subclasses:

FIFOSemaphore, PrioritySemaphore

public abstract class QueuedSemaphore
extends Semaphore

Abstract base class for semaphores relying on queued wait nodes.

[ Introduction to this package. ]

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	QueuedSemaphore.WaitQueue	Base class for internal queue classes for semaphores, etc.

Field Summary

Fields

Modifier and Type	Field	Description
protected final QueuedSemaphore.WaitQueue	wq_

Fields inherited from class Semaphore

permits_

Fields inherited from interface Sync

ONE_CENTURY, ONE_DAY, ONE_HOUR, ONE_MINUTE, ONE_SECOND, ONE_WEEK, ONE_YEAR

Method Summary

Modifier and Type	Method	Description
void	acquire()	Wait until a permit is available, and take one
boolean	attempt(long msecs)	Wait at most msecs millisconds for a permit.
protected QueuedSemaphore.WaitQueue.WaitNode	getSignallee()
protected boolean	precheck()
protected boolean	recheck(QueuedSemaphore.WaitQueue.WaitNode w)
void	release()	Release a permit
void	release(long n)	Release N permits

Methods inherited from class Semaphore

permits

Methods inherited from class Object

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

Field Details

wq_

protected final QueuedSemaphore.WaitQueue wq_

Method Details

acquire

public void acquire()
             throws InterruptedException

Description copied from class: Semaphore

Wait until a permit is available, and take one

Specified by:

acquire in interface Sync

Overrides:

acquire in class Semaphore

Throws:

InterruptedException

attempt

public boolean attempt(long msecs)
                throws InterruptedException

Description copied from class: Semaphore

Wait at most msecs millisconds for a permit.

Specified by:

attempt in interface Sync

Overrides:

attempt in class Semaphore

Parameters:

msecs - the number of milleseconds to wait. An argument less than or equal to zero means not to wait at all. However, this may still require access to a synchronization lock, which can impose unbounded delay if there is a lot of contention among threads.

Returns:

true if acquired

Throws:

InterruptedException

precheck

protected boolean precheck()

recheck

protected boolean recheck(QueuedSemaphore.WaitQueue.WaitNode w)

getSignallee

protected QueuedSemaphore.WaitQueue.WaitNode getSignallee()

release

public void release()

Description copied from class: Semaphore

Release a permit

Specified by:

release in interface Sync

Overrides:

release in class Semaphore

release

public void release(long n)

Release N permits

Overrides:

release in class Semaphore