Package pl.allegro.tech.hermes.consumers.consumer.rate

Class AdjustableSemaphore

java.lang.Object

pl.allegro.tech.hermes.consumers.consumer.rate.AdjustableSemaphore

@ThreadSafe
public final class AdjustableSemaphore
extends Object

A simple implementation of an adjustable semaphore.

Constructor Summary

Constructors

Constructor	Description
AdjustableSemaphore(int maxPermits)	New instances should be configured with setMaxPermits().

Method Summary

Modifier and Type	Method	Description
void	acquire()	Get a permit, blocking if necessary.
int	availablePermits()
void	release()	Release a permit back to the semaphore.
void	setMaxPermits(int newMax)	Set the max number of permits.
boolean	tryAcquire(long timeout, TimeUnit unit)

Methods inherited from class java.lang.Object

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

Constructor Details

AdjustableSemaphore

public AdjustableSemaphore(int maxPermits)

New instances should be configured with setMaxPermits().

Method Details

setMaxPermits

public void setMaxPermits(int newMax)

Set the max number of permits. Must be greater than zero.

Note that if there are more than the new max number of permits currently outstanding, any currently blocking threads or any new threads that start to block after the call will wait until enough permits have been released to have the number of outstanding permits fall below the new maximum. In other words, it does what you probably think it should.

release

public void release()

Release a permit back to the semaphore. Make sure not to double-release.

acquire

public void acquire()
             throws InterruptedException

Get a permit, blocking if necessary.

Throws:

InterruptedException - if interrupted while waiting for a permit

tryAcquire

public boolean tryAcquire(long timeout,
 TimeUnit unit)
                   throws InterruptedException

Throws:

InterruptedException

availablePermits

public int availablePermits()