org.jboss.ejb.plugins.lock
Class BeanLockSupport

java.lang.Object
  org.jboss.ejb.plugins.lock.BeanLockSupport

All Implemented Interfaces:

BeanLock, BeanLockExt, org.jboss.util.deadlock.Resource

Direct Known Subclasses:

NoLock, QueuedPessimisticEJBLock, SimpleReadWriteEJBLock

public abstract class BeanLockSupport
extends Object
implements org.jboss.util.deadlock.Resource, BeanLockExt

Support for the BeanLock

Version:

$Revision: 57209 $

Author:

Bill Burke, Marc Fleury

Field Summary

protected Container	container
protected Object	id The Cachekey corresponding to this Bean
protected int	refs Number of threads that retrieved this lock from the manager (0 means removing)
protected Thread	synched
protected int	synchedDepth
protected Transaction	tx Transaction holding lock on bean
protected int	txTimeout

Constructor Summary

BeanLockSupport()

Method Summary

void	addRef() Increment the reference count of this lock.
boolean	attemptSync() A non-blocking method that checks if the calling thread will be able to acquire the sync lock based on the calling thread.
abstract void	endInvocation(Invocation mi) Callback to the BeanLock to inform it that a method invocation has ended.
abstract void	endTransaction(Transaction tx) Informs the lock that the given transaction has ended.
Object	getId() Get the bean instance cache id for the bean we are locking for.
int	getRefs() Get the current reference count of this lock.
Object	getResourceHolder()
Transaction	getTransaction() Get the transaction currently associated with this lock.
void	releaseSync() Release exclusive access to this lock instance.
void	removeRef() Decrement the reference count of this lock.
abstract void	schedule(Invocation mi) This method implements the actual logic of the lock.
void	setContainer(Container container) set the ejb container of this lock.
void	setId(Object id) Set the bean instance cache id for the bean we are locking for.
void	setTimeout(int timeout) Change long we should wait for a lock.
void	setTransaction(Transaction tx) The setTransaction associates a transaction with the lock.
void	sync() A method that checks if the calling thread has the lock, and if it does not blocks until the lock is available.
abstract void	wontSynchronize(Transaction tx) Signifies to the lock that the transaction will not Synchronize (Tx demarcation not seen).

Methods inherited from class java.lang.Object

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

Field Detail

container

protected Container container

refs

protected int refs

Number of threads that retrieved this lock from the manager (0 means removing)

id

protected Object id

The Cachekey corresponding to this Bean

tx

protected Transaction tx

Transaction holding lock on bean

synched

protected Thread synched

synchedDepth

protected int synchedDepth

txTimeout

protected int txTimeout

Constructor Detail

BeanLockSupport

public BeanLockSupport()

Method Detail

setId

public void setId(Object id)

Description copied from interface: BeanLock

Set the bean instance cache id for the bean we are locking for.

Specified by:

setId in interface BeanLock

Parameters:

id - The cache key for the bean instance we are locking for.

getId

public Object getId()

Description copied from interface: BeanLock

Get the bean instance cache id for the bean we are locking for.

Specified by:

getId in interface BeanLock

Returns:

The cache key for the bean instance we are locking for.

setTimeout

public void setTimeout(int timeout)

Description copied from interface: BeanLock

Change long we should wait for a lock.

Specified by:

setTimeout in interface BeanLock

setContainer

public void setContainer(Container container)

Description copied from interface: BeanLock

set the ejb container of this lock.

Specified by:

setContainer in interface BeanLock

getResourceHolder

public Object getResourceHolder()

Specified by:

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

attemptSync

public boolean attemptSync()

A non-blocking method that checks if the calling thread will be able to acquire the sync lock based on the calling thread.

Specified by:

attemptSync in interface BeanLockExt

Returns:

true if the calling thread can obtain the sync lock in which case it will, false if another thread already has the lock.

sync

public void sync()

A method that checks if the calling thread has the lock, and if it does not blocks until the lock is available. If there is no current owner of the lock, or the calling thread already owns the lock then the calling thread will immeadiately acquire the lock.

Specified by:

sync in interface BeanLock

releaseSync

public void releaseSync()

Description copied from interface: BeanLock

Release exclusive access to this lock instance.

Specified by:

releaseSync in interface BeanLock

schedule

public abstract void schedule(Invocation mi)
                       throws Exception

Description copied from interface: BeanLock

This method implements the actual logic of the lock. In the case of an EJB lock it must at least implement the serialization of calls

Specified by:

schedule in interface BeanLock

Parameters:

mi - The method invocation that needs a lock.

Throws:

Exception

setTransaction

public void setTransaction(Transaction tx)

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

Specified by:

setTransaction in interface BeanLock

Parameters:

tx - The transaction to associate with this lock.

getTransaction

public Transaction getTransaction()

Description copied from interface: BeanLock

Get the transaction currently associated with this lock.

Specified by:

getTransaction in interface BeanLock

Returns:

The transaction currently associated with this lock, or null if no transaction is currently associated with this lock.

endTransaction

public abstract void endTransaction(Transaction tx)

Description copied from interface: BeanLock

Informs the lock that the given transaction has ended.

Specified by:

endTransaction in interface BeanLock

Parameters:

tx - The transaction that has ended.

wontSynchronize

public abstract void wontSynchronize(Transaction tx)

Description copied from interface: BeanLock

Signifies to the lock that the transaction will not Synchronize (Tx demarcation not seen).

OSH: This method does not seem to be called from anywhere. What is it meant for? To be called on a timeout before the transaction has terminated?

Specified by:

wontSynchronize in interface BeanLock

endInvocation

public abstract void endInvocation(Invocation mi)

Description copied from interface: BeanLock

Callback to the BeanLock to inform it that a method invocation has ended. A common use of this method is to release a method lock.

Specified by:

endInvocation in interface BeanLock

addRef

public void addRef()

Description copied from interface: BeanLock

Increment the reference count of this lock.

Specified by:

addRef in interface BeanLock

removeRef

public void removeRef()

Description copied from interface: BeanLock

Decrement the reference count of this lock.

Specified by:

removeRef in interface BeanLock

getRefs

public int getRefs()

Description copied from interface: BeanLock

Get the current reference count of this lock.

Specified by:

getRefs in interface BeanLock

Returns:

The current reference count.