Package com.composum.sling.core.concurrent

Class SemaphoreSequencer

java.lang.Object

com.composum.sling.core.concurrent.SemaphoreSequencer

All Implemented Interfaces:

SequencerService<SemaphoreSequencer.Token>

public class SemaphoreSequencer
extends Object
implements SequencerService<SemaphoreSequencer.Token>

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	SemaphoreSequencer.Token

Constructor Summary

Constructors

Constructor	Description
SemaphoreSequencer()

Method Summary

Modifier and Type	Method	Description
@NotNull SemaphoreSequencer.Token	acquire(String key)	Ensures the exclusiveness regarding the 'key' bind to the returned token.
protected void	activate(org.osgi.service.component.ComponentContext context)
protected void	cleanOldSemaphores(Map<SemaphoreSequencer.Token,WeakReference<SemaphoreSequencer.Token>> tokensToClear)
protected void	deactivate(org.osgi.service.component.ComponentContext context)	We release all locks currently held to unblock threads waiting for something.
void	release(SemaphoreSequencer.Token token)	Stops the exclusive access to the 'key' encapsulated in the token which was generated by the corresponding 'acquire()'.

Methods inherited from class java.lang.Object

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

Constructor Detail

SemaphoreSequencer

public SemaphoreSequencer()

Method Detail

acquire

@NotNull
public @NotNull SemaphoreSequencer.Token acquire(String key)

Description copied from interface: SequencerService

Ensures the exclusiveness regarding the 'key' bind to the returned token. Remember to use this in a try finally with SequencerService.release(Token).

Specified by:

acquire in interface SequencerService<SemaphoreSequencer.Token>

Returns:

the token which is necessary to release the binding

release

public void release(SemaphoreSequencer.Token token)

Description copied from interface: SequencerService

Stops the exclusive access to the 'key' encapsulated in the token which was generated by the corresponding 'acquire()'. Must be called after a successful SequencerService.acquire(String), and the Token must be discarded afterwards.

Specified by:

release in interface SequencerService<SemaphoreSequencer.Token>

activate

protected void activate(org.osgi.service.component.ComponentContext context)

deactivate

protected void deactivate(org.osgi.service.component.ComponentContext context)

We release all locks currently held to unblock threads waiting for something. That can break our users, but what can you do when the service is deactivated? That's probably better than having blocked threads lying around.

cleanOldSemaphores

protected void cleanOldSemaphores(Map<SemaphoreSequencer.Token,WeakReference<SemaphoreSequencer.Token>> tokensToClear)