net.tascalate.concurrent.locks

Class DefaultAsyncSemaphore

java.lang.Object

net.tascalate.concurrent.locks.DefaultAsyncSemaphore

All Implemented Interfaces:

AsyncSemaphore

public class DefaultAsyncSemaphore
extends Object
implements AsyncSemaphore

Constructor Summary

Constructors

Constructor and Description
DefaultAsyncSemaphore(long totalPermits, boolean fair)

Method Summary

Modifier and Type	Method and Description
Promise<T>	acquire(long permits)
long	availablePermits()
protected net.tascalate.concurrent.locks.DefaultAsyncSemaphore.SemaphorePromise	createPromise(long permits)
protected Long	createPromisePayload(long permits)
long	drainPermits() Acquires all permits that are immediately available.
int	getQueueLength()
void	release(long permits) Releases the given number of permits to the semaphore.
String	toString()
boolean	tryAcquire(long permits) Attempts to acquire the given number of permits from the semaphore, returning a boolean indicating whether all of the permits were immediately available and have been exclusively acquired.

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.tascalate.concurrent.locks.AsyncSemaphore

acquire, acquire, availablePermits, create, getQueueLength, release, tryAcquire

Constructor Detail

DefaultAsyncSemaphore

public DefaultAsyncSemaphore(long totalPermits,
                             boolean fair)

Method Detail

drainPermits

public long drainPermits()

Description copied from interface: AsyncSemaphore

Acquires all permits that are immediately available.

After this call -- provided there are no intermediate releases -- any attempt to acquire will queue and any tryAcquire will fail.

Specified by:

drainPermits in interface AsyncSemaphore

Returns:

the number of permits that were available and have been drained

tryAcquire

public boolean tryAcquire(long permits)

Description copied from interface: AsyncSemaphore

Attempts to acquire the given number of permits from the semaphore, returning a boolean indicating whether all of the permits were immediately available and have been exclusively acquired.

Implementations may define precise behavior of this method with respect to competing acquisitions, e.g. whether permits may be acquired while other acquisitions are waiting. This interface only requires that this method will succeed when the given permits are available and there are no other acquisitions queued.

Specified by:

tryAcquire in interface AsyncSemaphore

Parameters:

permits - A non-negative number of permits to acquire from the semaphore

Returns:

true if all of the requested permits are available, and have been immediately acquired

release

public void release(long permits)

Description copied from interface: AsyncSemaphore

Releases the given number of permits to the semaphore.

If there are unfulfilled acquires pending, this method will release permits to the waiting acquisitions based on the implementation's release and acquire policies. Consequently, this method may complete a number of waiting stages and execute the corresponding observers.

Specified by:

release in interface AsyncSemaphore

Parameters:

permits - A non-negative number of permits to release to the semaphore

createPromisePayload

protected Long createPromisePayload(long permits)

createPromise

protected net.tascalate.concurrent.locks.DefaultAsyncSemaphore.SemaphorePromise createPromise(long permits)

availablePermits

public long availablePermits()

getQueueLength

public int getQueueLength()

acquire

public Promise<T> acquire(long permits)

toString

public String toString()

Overrides:

toString in class Object