org.elasticsearch.common.util.concurrent

Class SuspendableRefContainer

java.lang.Object

org.elasticsearch.common.util.concurrent.SuspendableRefContainer

public final class SuspendableRefContainer
extends java.lang.Object

Container that represents a resource with reference counting capabilities. Provides operations to suspend acquisition of new references. This is useful for resource management when resources are intermittently unavailable. Assumes less than Integer.MAX_VALUE references are concurrently being held at one point in time.

Constructor Summary

Constructors

Constructor and Description
SuspendableRefContainer()

Method Summary

Modifier and Type	Method and Description
Releasable	acquire() Acquires a reference.
Releasable	acquireUninterruptibly() Acquires a reference.
int	activeRefs() Returns the number of references currently being held.
Releasable	blockAcquisition() Disables reference acquisition and waits until all existing references are released.
Releasable	tryAcquire() Tries acquiring a reference.

Methods inherited from class java.lang.Object

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

Constructor Detail

SuspendableRefContainer

public SuspendableRefContainer()

Method Detail

tryAcquire

public Releasable tryAcquire()
                      throws java.lang.InterruptedException

Tries acquiring a reference. Returns reference holder if reference acquisition is not blocked at the time of invocation (see blockAcquisition()). Returns null if reference acquisition is blocked at the time of invocation.

Returns:

reference holder if reference acquisition is not blocked, null otherwise

Throws:

java.lang.InterruptedException - if the current thread is interrupted

acquire

public Releasable acquire()
                   throws java.lang.InterruptedException

Acquires a reference. Blocks if reference acquisition is blocked at the time of invocation.

Returns:

reference holder

Throws:

java.lang.InterruptedException - if the current thread is interrupted

acquireUninterruptibly

public Releasable acquireUninterruptibly()

Acquires a reference. Blocks if reference acquisition is blocked at the time of invocation.

Returns:

reference holder

blockAcquisition

public Releasable blockAcquisition()

Disables reference acquisition and waits until all existing references are released. When released, reference acquisition is enabled again. This guarantees that between successful acquisition and release, no one is holding a reference.

Returns:

references holder to all references

activeRefs

public int activeRefs()

Returns the number of references currently being held.