com.facebook.buck.util.concurrent

Class ListeningMultiSemaphore

java.lang.Object

com.facebook.buck.util.concurrent.ListeningMultiSemaphore

public class ListeningMultiSemaphore
extends Object

A semaphore using ListenableFutures for acquisition of different resource types rather than blocking.

Constructor Summary

Constructors

Constructor and Description
ListeningMultiSemaphore(ResourceAmounts availableResources, ResourceAllocationFairness fairness)

Method Summary

Modifier and Type	Method and Description
com.google.common.util.concurrent.ListenableFuture<Unit>	acquire(ResourceAmounts resources) Returns the future which will be completed by the moment when resources will be acquired.
ResourceAmounts	getAvailableResources()
ResourceAmounts	getMaximumValues()
int	getQueueLength()
void	release(ResourceAmounts resources) Releases previously acquired resources.

Methods inherited from class java.lang.Object

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

Constructor Detail

ListeningMultiSemaphore

public ListeningMultiSemaphore(ResourceAmounts availableResources,
                               ResourceAllocationFairness fairness)

Method Detail

acquire

public com.google.common.util.concurrent.ListenableFuture<Unit> acquire(ResourceAmounts resources)

Returns the future which will be completed by the moment when resources will be acquired. Future may be returned already completed. You should subscribe to the future and perform your resource requiring job once the future will be completed and not cancelled. When you finish your job, you must release acquired resources by calling release() method below.

Parameters:

resources - Resource amounts that need to be acquired. If they are higher than maximum amounts, they will be capped to them.

Returns:

Future that will be completed once resource will be acquired.

release

public void release(ResourceAmounts resources)

Releases previously acquired resources.

Parameters:

resources - Resource amounts that need to be released. This argument should match one you used during resource acquiring.

getAvailableResources

public ResourceAmounts getAvailableResources()

getMaximumValues

public ResourceAmounts getMaximumValues()

getQueueLength

public int getQueueLength()