org.apache.curator.framework.recipes.locks

Class InterProcessSemaphoreMutex

java.lang.Object

org.apache.curator.framework.recipes.locks.InterProcessSemaphoreMutex

All Implemented Interfaces:

InterProcessLock

public class InterProcessSemaphoreMutex
extends Object
implements InterProcessLock

A NON re-entrant mutex that works across JVMs. Uses Zookeeper to hold the lock. All processes in all JVMs that use the same lock path will achieve an inter-process critical section.

Constructor Summary

Constructors

Constructor and Description
InterProcessSemaphoreMutex(CuratorFramework client, String path)

Method Summary

Modifier and Type	Method and Description
void	acquire() Acquire the mutex - blocking until it's available.
boolean	acquire(long time, TimeUnit unit) Acquire the mutex - blocks until it's available or the given time expires.
boolean	isAcquiredInThisProcess() Returns true if the mutex is acquired by a thread in this JVM
void	release() Perform one release of the mutex.

Methods inherited from class java.lang.Object

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

Constructor Detail

InterProcessSemaphoreMutex

public InterProcessSemaphoreMutex(CuratorFramework client,
                                  String path)

Parameters:

client - the client

path - path for the lock

Method Detail

acquire

public void acquire()
             throws Exception

Description copied from interface: InterProcessLock

Acquire the mutex - blocking until it's available. Each call to acquire must be balanced by a call to InterProcessLock.release()

Specified by:

acquire in interface InterProcessLock

Throws:

Exception - ZK errors, connection interruptions

acquire

public boolean acquire(long time,
                       TimeUnit unit)
                throws Exception

Description copied from interface: InterProcessLock

Acquire the mutex - blocks until it's available or the given time expires. Each call to acquire that returns true must be balanced by a call to InterProcessLock.release()

Specified by:

acquire in interface InterProcessLock

Parameters:

time - time to wait

unit - time unit

Returns:

true if the mutex was acquired, false if not

Throws:

Exception - ZK errors, connection interruptions

release

public void release()
             throws Exception

Perform one release of the mutex.

NOTE: Unlike other implementations of InterProcessLock.release(), this method will NOT throw an exception if it is called on a different thread than the one which acquired the lock.

Specified by:

release in interface InterProcessLock

Throws:

Exception - ZK errors, interruptions

isAcquiredInThisProcess

public boolean isAcquiredInThisProcess()

Description copied from interface: InterProcessLock

Returns true if the mutex is acquired by a thread in this JVM

Specified by:

isAcquiredInThisProcess in interface InterProcessLock

Returns:

true/false