org.jboss.aspects.txlock
Class QueuedTxLock

java.lang.Object
  org.jboss.aspects.txlock.QueuedTxLock

All Implemented Interfaces:

org.jboss.util.deadlock.Resource

public class QueuedTxLock
extends Object
implements org.jboss.util.deadlock.Resource

This class is holds threads awaiting the transactional lock to be free in a fair FIFO transactional queue. Non-transactional threads are also put in this wait queue as well. This class pops the next waiting transaction from the queue and notifies only those threads waiting associated with that transaction. As of 04/10/2002, you can now specify in jboss.xml method attributes that define methods as read-only. read-only methods(and read-only beans) will release transactional locks at the end of the invocation. This decreases likelyhood of deadlock and increases performance. FIXME marcf: we should get solid numbers on this locking, bench in multi-thread environments We need someone with serious SUN hardware to run this lock into the ground

Version:

$Revision: 1.1.4.3 $

Author:

Marc Fleury, Bill Burke

Field Summary

static String	TIMEOUT
static String	TXLOCK

Constructor Summary

QueuedTxLock()

Method Summary

void	endInvocation(Transaction thetx)
void	endTransaction()
Object	getResourceHolder()
Transaction	getTransaction()
protected org.jboss.aspects.txlock.QueuedTxLock.TxLock	getTxLock(Transaction miTx)
protected boolean	isTxExpired(Transaction miTx)
boolean	lockNoWait(Transaction transaction)
protected void	nextTransaction(boolean trace)
void	releaseSync()
void	schedule(Transaction miTx, org.jboss.aop.joinpoint.Invocation mi) doSchedule(Invocation) doSchedule implements a particular policy for scheduling the threads coming in.
void	setTransaction(Transaction tx) The setTransaction associates a transaction with the lock.
void	sync()
String	toString()
protected void	waitForTx(org.jboss.aop.joinpoint.Invocation mi, Transaction miTx, boolean trace) Wait until no other transaction is running with this lock.

Methods inherited from class java.lang.Object

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

Field Detail

TXLOCK

public static final String TXLOCK

See Also:

Constant Field Values

TIMEOUT

public static final String TIMEOUT

See Also:

Constant Field Values

Constructor Detail

QueuedTxLock

public QueuedTxLock()

Method Detail

getResourceHolder

public Object getResourceHolder()

Specified by:

getResourceHolder in interface org.jboss.util.deadlock.Resource

sync

public void sync()
          throws InterruptedException

Throws:

InterruptedException

releaseSync

public void releaseSync()

setTransaction

public void setTransaction(Transaction tx)

The setTransaction associates a transaction with the lock. The current transaction is associated by the schedule call.

getTransaction

public Transaction getTransaction()

getTxLock

protected org.jboss.aspects.txlock.QueuedTxLock.TxLock getTxLock(Transaction miTx)

isTxExpired

protected boolean isTxExpired(Transaction miTx)
                       throws Exception

Throws:

Exception

lockNoWait

public boolean lockNoWait(Transaction transaction)
                   throws Exception

Throws:

Exception

schedule

public void schedule(Transaction miTx,
                     org.jboss.aop.joinpoint.Invocation mi)
              throws Exception

doSchedule(Invocation) doSchedule implements a particular policy for scheduling the threads coming in. There is always the spec required "serialization" but we can add custom scheduling in here Synchronizing on lock: a failure to get scheduled must result in a wait() call and a release of the lock. Schedulation must return with lock.

Throws:

Exception

waitForTx

protected void waitForTx(org.jboss.aop.joinpoint.Invocation mi,
                         Transaction miTx,
                         boolean trace)
                  throws Exception

Wait until no other transaction is running with this lock.

Throws:

Exception

nextTransaction

protected void nextTransaction(boolean trace)

endTransaction

public void endTransaction()

endInvocation

public void endInvocation(Transaction thetx)

toString

public String toString()

Overrides:

toString in class Object