org.jgroups.blocks.locking

Class LockService

java.lang.Object

org.jgroups.blocks.locking.LockService

public class LockService
extends java.lang.Object

LockService is the main class for to use for distributed locking functionality. LockService needs access to a Channel and interacts with a locking protocol (e.g. CENTRAL_LOCK) via events.

When no locking protocol is seen on the channel's stack, LockService will throw an exception at startup. An example of using LockService is:

   JChannel ch=new JChannel("/home/bela/locking.xml); // locking.xml needs to have a locking protocol towards the top
   LockService lock_service=new LockService(ch);
   ch.connect("lock-cluster");
   Lock lock=lock_service.getLock("mylock");
   lock.lock();
   try {
      // do something with the lock acquired
   }
   finally {
      lock.unlock();
   }
 

The exact semantics of this lock implemantation are defined in LockService.LockImpl.

Note that, contrary to the semantics of Lock, unlock() can be called multiple times; after a lock has been released, future calls to unlock() have no effect.

Since:

2.12

Author:

Bela Ban

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	LockService.LockImpl Implementation of Lock.

Field Summary

Fields

Modifier and Type	Field and Description
protected Channel	ch
protected Locking	lock_prot

Constructor Summary

Constructors

Constructor and Description
LockService()
LockService(Channel ch)

Method Summary

Modifier and Type	Method and Description
void	addLockListener(LockNotification listener)
java.util.concurrent.locks.Lock	getLock(java.lang.String lock_name)
java.lang.String	printLocks()
void	removeLockListener(LockNotification listener)
void	setChannel(Channel ch)
void	unlockAll()

Methods inherited from class java.lang.Object

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

Field Detail

ch

protected Channel ch

lock_prot

protected Locking lock_prot

Constructor Detail

LockService

public LockService()

LockService

public LockService(Channel ch)

Method Detail

setChannel

public void setChannel(Channel ch)

getLock

public java.util.concurrent.locks.Lock getLock(java.lang.String lock_name)

unlockAll

public void unlockAll()

addLockListener

public void addLockListener(LockNotification listener)

removeLockListener

public void removeLockListener(LockNotification listener)

printLocks

public java.lang.String printLocks()