EDU.oswego.cs.dl.util.concurrent
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

protected static class

QueuedSemaphore.WaitQueue Base class for internal queue classes for semaphores, etc.

Field Summary

protected QueuedSemaphore.WaitQueue

wq_

Fields inherited from class EDU.oswego.cs.dl.util.concurrent.Semaphore

permits_

Fields inherited from interface EDU.oswego.cs.dl.util.concurrent.Sync

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

Method Summary

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

permits

Methods inherited from class java.lang.Object

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

Field Detail

wq_

protected final QueuedSemaphore.WaitQueue wq_

Method Detail

acquire

public void acquire()
             throws java.lang.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:

java.lang.InterruptedException

attempt

public boolean attempt(long msecs)
                throws java.lang.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:

java.lang.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