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JBoss API: Class EntityInstanceInterceptor

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org.jboss.ejb.plugins
Class EntityInstanceInterceptor

java.lang.Object
  |
  +--org.jboss.ejb.plugins.AbstractInterceptor
        |
        +--org.jboss.ejb.plugins.EntityInstanceInterceptor

All Implemented Interfaces:: ContainerPlugin, Interceptor, Service

public class EntityInstanceInterceptor
extends AbstractInterceptor

The instance interceptors role is to acquire a context representing the target object from the cache.

This particular container interceptor implements pessimistic locking on the transaction that is associated with the retrieved instance. If there is a transaction associated with the target component and it is different from the transaction associated with the MethodInvocation coming in then the policy is to wait for transactional commit.

We also implement serialization of calls in here (this is a spec requirement). This is a fine grained notify, notifyAll mechanism. We notify on ctx serialization locks and notifyAll on global transactional locks.

WARNING: critical code, get approval from senior developers before changing.

Version:

$Revision: 1.30.2.8 $

Revisions:

2001/06/28: marcf

Moved to new synchronization
Pools are gone simple design
two levels of syncrhonization with Tx and ctx
remove busy wait from previous mechanisms

2001/07/11: starksm

Fix a thread starvation problem due to incomplete condition notification
Add support for trace level diagnositics

2001/07/12: starksm

Handle a race condition when there is no ctx transaction

2001/07/16: billb

Added wait(timeout) code, commented out so that we can easily turn it on when this new code is done with it's trial period.
Fixed bug when ejbLoad threw an exception and threads waiting on TxLock did not get awakened.

2001/07/26: billb

Locking is now separate from EntityEnterpriseContext objects and is now encapsulated in BeanLock and BeanLockManager. Did this because the lifetime of an EntityLock is sometimes longer than the lifetime of the ctx.

2001/08/1: marcf

Taking the lock out pointed to something new, the fact that the locking policies can be fully automated and factored out of the instance interceptor this results in a new interceptor EntityLockInterceptor that by design sits in front of this one in the chain of interceptors.
This interceptor is greatly simplified and all it does is retrieve the instance from cache
Scheduling is implemented in new interceptor, all notify policies gone, simple
For the record, locking went from cache (early 2.0) -> this interceptor -> new interceptor
new locking is pluggable

2001/10/18: billb

Do not insert bean into cache on an exception

Author:

Marc Fleury, Scott Stark, Bill Burke

Field Summary

protected EntityContainer container


Fields inherited from class org.jboss.ejb.plugins.AbstractInterceptor

log, nextInterceptor

Constructor Summary

EntityInstanceInterceptor()


Method Summary

Container getContainer()


java.lang.Object invoke(MethodInvocation mi)


java.lang.Object invokeHome(MethodInvocation mi)


void setContainer(Container container)
          This callback is set by the container so that the plugin may access it

Methods inherited from class org.jboss.ejb.plugins.AbstractInterceptor

destroy, getNext, init, setNext, start, stop

Methods inherited from class java.lang.Object

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

Field Detail

container

protected EntityContainer container

Constructor Detail

EntityInstanceInterceptor

public EntityInstanceInterceptor()

Method Detail

setContainer

public void setContainer(Container container)

Description copied from interface: ContainerPlugin

This callback is set by the container so that the plugin may access it

Overrides:: setContainer in class AbstractInterceptor

Following copied from interface: org.jboss.ejb.ContainerPlugin

Parameters:: con - the container using this plugin

getContainer

public Container getContainer()

Overrides:: getContainer in class AbstractInterceptor

invokeHome

public java.lang.Object invokeHome(MethodInvocation mi)
                            throws java.lang.Exception

Overrides:: invokeHome in class AbstractInterceptor

invoke

public java.lang.Object invoke(MethodInvocation mi)
                        throws java.lang.Exception

Overrides:: invoke in class AbstractInterceptor