org.jboss.cache.util.concurrent.locks

Class OwnableReentrantLock

java.lang.Object

java.util.concurrent.locks.AbstractOwnableSynchronizer

java.util.concurrent.locks.AbstractQueuedSynchronizer

org.jboss.cache.util.concurrent.locks.OwnableReentrantLock

All Implemented Interfaces:

Serializable, Lock

@ThreadSafe
public class OwnableReentrantLock
extends AbstractQueuedSynchronizer
implements Lock

A lock that supports reentrancy based on owner (and not on current thread). For this to work, the lock needs to be constructed with a reference to the InvocationContextContainer, so it is able to determine whether the caller's "owner" reference is the current thread or a GlobalTransaction instance.

This makes this lock implementation very closely tied to JBoss Cache internals, but it provides for a very clean, efficient and moreover familiar interface to work with, since it implements Lock.

For the sake of performance, this lock only supports nonfair queueing.

Since:

3.0

Author:

Manik Surtani (manik AT jboss DOT org)

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

AbstractQueuedSynchronizer.ConditionObject

Constructor Summary

Constructors

Constructor and Description
OwnableReentrantLock(InvocationContextContainer invocationContextContainer) Creates a new lock instance.

Method Summary

Methods

Modifier and Type	Method and Description
protected Object	currentRequestor()
int	getHoldCount()
Object	getOwner()
protected boolean	isHeldExclusively()
boolean	isLocked()
void	lock()
void	lockInterruptibly()
AbstractQueuedSynchronizer.ConditionObject	newCondition()
String	toString() Returns a string identifying this lock, as well as its lock state.
protected boolean	tryAcquire(int acquires)
boolean	tryLock()
boolean	tryLock(long time, TimeUnit unit)
protected boolean	tryRelease(int releases)
void	unlock()

Methods inherited from class java.util.concurrent.locks.AbstractQueuedSynchronizer

acquire, acquireInterruptibly, acquireShared, acquireSharedInterruptibly, compareAndSetState, getExclusiveQueuedThreads, getFirstQueuedThread, getQueuedThreads, getQueueLength, getSharedQueuedThreads, getState, getWaitingThreads, getWaitQueueLength, hasContended, hasQueuedPredecessors, hasQueuedThreads, hasWaiters, isQueued, owns, release, releaseShared, setState, tryAcquireNanos, tryAcquireShared, tryAcquireSharedNanos, tryReleaseShared

Methods inherited from class java.util.concurrent.locks.AbstractOwnableSynchronizer

getExclusiveOwnerThread, setExclusiveOwnerThread

Methods inherited from class java.lang.Object

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

Constructor Detail

OwnableReentrantLock

public OwnableReentrantLock(InvocationContextContainer invocationContextContainer)

Creates a new lock instance.

Parameters:

invocationContextContainer - InvocationContextContainer instance to consult for the invocation context of the call.

Method Detail

currentRequestor

protected final Object currentRequestor()

Returns:

a GlobalTransaction instance if the current call is participating in a transaction, or the current thread otherwise.

lock

public void lock()

Specified by:

lock in interface Lock

lockInterruptibly

public void lockInterruptibly()
                       throws InterruptedException

Specified by:

lockInterruptibly in interface Lock

Throws:

InterruptedException

tryLock

public boolean tryLock()

Specified by:

tryLock in interface Lock

tryLock

public boolean tryLock(long time,
              TimeUnit unit)
                throws InterruptedException

Specified by:

tryLock in interface Lock

Throws:

InterruptedException

unlock

public void unlock()

Specified by:

unlock in interface Lock

newCondition

public AbstractQueuedSynchronizer.ConditionObject newCondition()

Specified by:

newCondition in interface Lock

tryAcquire

protected final boolean tryAcquire(int acquires)

Overrides:

tryAcquire in class AbstractQueuedSynchronizer

tryRelease

protected final boolean tryRelease(int releases)

Overrides:

tryRelease in class AbstractQueuedSynchronizer

isHeldExclusively

protected final boolean isHeldExclusively()

Overrides:

isHeldExclusively in class AbstractQueuedSynchronizer

getOwner

public final Object getOwner()

Returns:

the owner of the lock, or null if it is currently unlocked.

getHoldCount

public final int getHoldCount()

Returns:

the hold count of the current lock, or 0 if it is not locked.

isLocked

public final boolean isLocked()

Returns:

true if the lock is locked, false otherwise

toString

public String toString()

Returns a string identifying this lock, as well as its lock state. The state, in brackets, includes either the String "Unlocked" or the String "Locked by" followed by the String representation of the lock owner.

Overrides:

toString in class AbstractQueuedSynchronizer

Returns:

a string identifying this lock, as well as its lock state.