/*
* JBoss, Home of Professional Open Source.
* Copyright (c) 2011, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.ejb3.component.stateful;
import javax.ejb.ConcurrentAccessTimeoutException;
import javax.ejb.EJBException;
import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.TransactionSynchronizationRegistry;
import org.jboss.as.ejb3.component.interceptors.AbstractEJBInterceptor;
import org.jboss.as.ejb3.concurrency.AccessTimeoutDetails;
import org.jboss.as.ejb3.tx.OwnableReentrantLock;
import org.jboss.invocation.InterceptorContext;
import static org.jboss.as.ejb3.EjbLogger.ROOT_LOGGER;
import static org.jboss.as.ejb3.EjbMessages.MESSAGES;
import static org.jboss.as.ejb3.component.stateful.StatefulComponentInstanceInterceptor.getComponentInstance;
/**
* {@link org.jboss.invocation.Interceptor} which manages {@link Synchronization} semantics on a stateful session bean.
*
* @author <a href="mailto:cdewolf@redhat.com">Carlo de Wolf</a>
* @author Jaikiran Pai
*/
public class StatefulSessionSynchronizationInterceptor extends AbstractEJBInterceptor {
private final Object threadLock = new Object();
private final OwnableReentrantLock lock = new OwnableReentrantLock();
private boolean synchronizationRegistered = false;
/**
* Handles the exception that occured during a {@link StatefulSessionSynchronization transaction synchronization} callback
* invocations.
* <p/>
* This method discards the <code>statefulSessionComponentInstance</code> before
* releasing the {@link #lock} held by this thread, for the <code>statefulSessionComponentInstance</code>
*
* @param statefulSessionComponentInstance
* The stateful component instance involved in the transaction
* @param t The {@link Throwable throwable}
* @return
*/
private Error handleThrowableInTxSync(final StatefulSessionComponentInstance statefulSessionComponentInstance, final Throwable t) {
ROOT_LOGGER.discardingStatefulComponent(statefulSessionComponentInstance, t);
try {
// discard the SFSB instance
statefulSessionComponentInstance.discard();
} finally {
// release the lock associated with the SFSB instance
this.releaseLock();
}
// throw back an appropriate exception
if (t instanceof RuntimeException)
throw (RuntimeException) t;
if (t instanceof Error)
throw (Error) t;
throw (EJBException) new EJBException().initCause(t);
}
@Override
public Object processInvocation(final InterceptorContext context) throws Exception {
final StatefulSessionComponent component = getComponent(context, StatefulSessionComponent.class);
final StatefulSessionComponentInstance instance = getComponentInstance(context);
final TransactionSynchronizationRegistry transactionSynchronizationRegistry = component.getTransactionSynchronizationRegistry();
final Object lockOwner = getLockOwner(transactionSynchronizationRegistry);
lock.pushOwner(lockOwner);
try {
final AccessTimeoutDetails timeout = component.getAccessTimeout(context.getMethod());
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("Trying to acquire lock: " + lock + " for stateful component instance: " + instance + " during invocation: " + context);
}
// we obtain a lock in this synchronization interceptor because the lock needs to be tied to the synchronization
// so that it can released on the tx synchronization callbacks
boolean acquired = lock.tryLock(timeout.getValue(), timeout.getTimeUnit());
if (!acquired) {
throw MESSAGES.failToObtainLock(context,timeout.getValue(),timeout.getTimeUnit());
}
synchronized (threadLock) {
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("Acquired lock: " + lock + " for stateful component instance: " + instance + " during invocation: " + context);
}
Object currentTransactionKey = null;
boolean wasTxSyncRegistered = false;
try {
if (!synchronizationRegistered) {
// get the key to current transaction associated with this thread
currentTransactionKey = transactionSynchronizationRegistry.getTransactionKey();
final int status = transactionSynchronizationRegistry.getTransactionStatus();
// if this SFSB instance is already associated with a different transaction, then it's an error
// if the thread is currently associated with a tx, then register a tx synchronization
if (currentTransactionKey != null && status != Status.STATUS_COMMITTED) {
// register a tx synchronization for this SFSB instance
final Synchronization statefulSessionSync = new StatefulSessionSynchronization(instance, lockOwner);
transactionSynchronizationRegistry.registerInterposedSynchronization(statefulSessionSync);
wasTxSyncRegistered = true;
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("Registered tx synchronization: " + statefulSessionSync + " for tx: " + currentTransactionKey +
" associated with stateful component instance: " + instance);
}
// invoke the afterBegin callback on the SFSB
instance.afterBegin();
}
synchronizationRegistered = true;
}
// proceed with the invocation
return context.proceed();
} finally {
// if the current call did *not* register a tx SessionSynchronization, then we have to explicitly mark the
// SFSB instance as "no longer in use". If it registered a tx SessionSynchronization, then releasing the lock is
// taken care off by a tx synchronization callbacks.
if (!wasTxSyncRegistered) {
releaseInstance(instance);
}
}
}
} finally {
lock.popOwner();
}
}
/**
* Use either the active transaction or the current thread as the lock owner
*
* @param transactionSynchronizationRegistry
* The synronization registry
* @return The lock owner
*/
private Object getLockOwner(final TransactionSynchronizationRegistry transactionSynchronizationRegistry) {
Object owner = transactionSynchronizationRegistry.getTransactionKey();
return owner != null ? owner : Thread.currentThread();
}
/**
* Releases the passed {@link StatefulSessionComponentInstance} i.e. marks it as no longer in use. After releasing the
* instance, this method releases the lock, held by this thread, on the stateful component instance.
*
* @param instance The stateful component instance
*/
private void releaseInstance(final StatefulSessionComponentInstance instance) {
try {
// mark the SFSB instance as no longer in use
instance.getComponent().getCache().release(instance);
} finally {
synchronizationRegistered = false;
// release the lock on the SFSB instance
this.releaseLock();
}
}
/**
* Releases the lock, held by this thread, on the stateful component instance.
*/
private void releaseLock() {
lock.unlock();
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("Released lock: " + lock);
}
}
private class StatefulSessionSynchronization implements Synchronization {
private final StatefulSessionComponentInstance statefulSessionComponentInstance;
private final Object lockOwner;
StatefulSessionSynchronization(StatefulSessionComponentInstance statefulSessionComponentInstance, final Object lockOwner) {
this.statefulSessionComponentInstance = statefulSessionComponentInstance;
this.lockOwner = lockOwner;
}
@Override
public void beforeCompletion() {
try {
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("Before completion callback invoked on Transaction synchronization: " + this +
" of stateful component instance: " + statefulSessionComponentInstance);
}
statefulSessionComponentInstance.beforeCompletion();
} catch (Throwable t) {
throw handleThrowableInTxSync(statefulSessionComponentInstance, t);
}
}
@Override
public void afterCompletion(int status) {
try {
if (ROOT_LOGGER.isTraceEnabled()) {
ROOT_LOGGER.trace("After completion callback invoked on Transaction synchronization: " + this +
" of stateful component instance: " + statefulSessionComponentInstance);
}
statefulSessionComponentInstance.afterCompletion(status == Status.STATUS_COMMITTED);
} catch (Throwable t) {
throw handleThrowableInTxSync(statefulSessionComponentInstance, t);
}
// tx has completed, so mark the SFSB instance as no longer in use
lock.pushOwner(lockOwner);
try {
releaseInstance(statefulSessionComponentInstance);
} finally {
lock.popOwner();
}
}
}
}