/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2008-2011, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program 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 distribution; if not, write to:
* Free Software Foundation, Inc.
* 51 Franklin Street, Fifth Floor
* Boston, MA 02110-1301 USA
*/
package org.hibernate.context.internal;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.transaction.Synchronization;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager;
import org.hibernate.ConnectionReleaseMode;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.context.spi.AbstractCurrentSessionContext;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.transaction.internal.jta.JtaStatusHelper;
import org.hibernate.engine.transaction.jta.platform.spi.JtaPlatform;
import org.hibernate.internal.CoreMessageLogger;
import org.jboss.logging.Logger;
/**
* An implementation of {@link org.hibernate.context.spi.CurrentSessionContext} which scopes the notion
* of a current session to a JTA transaction. Because JTA gives us a nice tie-in to clean up after
* ourselves, this implementation will generate Sessions as needed provided a JTA transaction is in
* effect. If a session is not already associated with the current JTA transaction at the time
* {@link #currentSession()} is called, a new session will be opened and it will be associated with that
* JTA transaction.
*
* Note that the sessions returned from this method are automatically configured with both the
* {@link org.hibernate.cfg.Environment#FLUSH_BEFORE_COMPLETION auto-flush} and
* {@link org.hibernate.cfg.Environment#AUTO_CLOSE_SESSION auto-close} attributes set to true, meaning
* that the Session will be automatically flushed and closed as part of the lifecycle for the JTA
* transaction to which it is associated. Additionally, it will also be configured to aggressively
* release JDBC connections after each statement is executed. These settings are governed by the
* {@link #isAutoFlushEnabled()}, {@link #isAutoCloseEnabled()}, and {@link #getConnectionReleaseMode()}
* methods; these are provided (along with the {@link #buildOrObtainSession()} method) for easier
* subclassing for custom JTA-based session tracking logic (like maybe long-session semantics).
*
* @author Steve Ebersole
*/
public class JTASessionContext extends AbstractCurrentSessionContext {
private static final CoreMessageLogger LOG = Logger.getMessageLogger(
CoreMessageLogger.class,
JTASessionContext.class.getName()
);
private transient Map<Object, Session> currentSessionMap = new ConcurrentHashMap<Object, Session>();
/**
* Constructs a JTASessionContext
*
* @param factory The factory this context will service
*/
public JTASessionContext(SessionFactoryImplementor factory) {
super( factory );
}
@Override
public Session currentSession() throws HibernateException {
final JtaPlatform jtaPlatform = factory().getServiceRegistry().getService( JtaPlatform.class );
final TransactionManager transactionManager = jtaPlatform.retrieveTransactionManager();
if ( transactionManager == null ) {
throw new HibernateException( "No TransactionManagerLookup specified" );
}
Transaction txn;
try {
txn = transactionManager.getTransaction();
if ( txn == null ) {
throw new HibernateException( "Unable to locate current JTA transaction" );
}
if ( !JtaStatusHelper.isActive( txn.getStatus() ) ) {
// We could register the session against the transaction even though it is
// not started, but we'd have no guarantee of ever getting the map
// entries cleaned up (aside from spawning threads).
throw new HibernateException( "Current transaction is not in progress" );
}
}
catch ( HibernateException e ) {
throw e;
}
catch ( Throwable t ) {
throw new HibernateException( "Problem locating/validating JTA transaction", t );
}
final Object txnIdentifier = jtaPlatform.getTransactionIdentifier( txn );
Session currentSession = currentSessionMap.get( txnIdentifier );
if ( currentSession == null ) {
currentSession = buildOrObtainSession();
try {
txn.registerSynchronization( buildCleanupSynch( txnIdentifier ) );
}
catch ( Throwable t ) {
try {
currentSession.close();
}
catch ( Throwable ignore ) {
LOG.debug( "Unable to release generated current-session on failed synch registration", ignore );
}
throw new HibernateException( "Unable to register cleanup Synchronization with TransactionManager" );
}
currentSessionMap.put( txnIdentifier, currentSession );
}
else {
validateExistingSession( currentSession );
}
return currentSession;
}
/**
* Builds a {@link org.hibernate.context.internal.JTASessionContext.CleanupSync} capable of cleaning up the the current session map as an after transaction
* callback.
*
* @param transactionIdentifier The transaction identifier under which the current session is registered.
* @return The cleanup synch.
*/
private CleanupSync buildCleanupSynch(Object transactionIdentifier) {
return new CleanupSync( transactionIdentifier, this );
}
/**
* Strictly provided for subclassing purposes; specifically to allow long-session
* support. This implementation always just opens a new session.
*
* @return the built or (re)obtained session.
*/
@SuppressWarnings("deprecation")
protected Session buildOrObtainSession() {
return baseSessionBuilder()
.autoClose( isAutoCloseEnabled() )
.connectionReleaseMode( getConnectionReleaseMode() )
.flushBeforeCompletion( isAutoFlushEnabled() )
.openSession();
}
/**
* Mainly for subclass usage. This impl always returns true.
*
* @return Whether or not the the session should be closed by transaction completion.
*/
protected boolean isAutoCloseEnabled() {
return true;
}
/**
* Mainly for subclass usage. This impl always returns true.
*
* @return Whether or not the the session should be flushed prior transaction completion.
*/
protected boolean isAutoFlushEnabled() {
return true;
}
/**
* Mainly for subclass usage. This impl always returns after_statement.
*
* @return The connection release mode for any built sessions.
*/
protected ConnectionReleaseMode getConnectionReleaseMode() {
return ConnectionReleaseMode.AFTER_STATEMENT;
}
/**
* JTA transaction sync used for cleanup of the internal session map.
*/
protected static class CleanupSync implements Synchronization {
private Object transactionIdentifier;
private JTASessionContext context;
public CleanupSync(Object transactionIdentifier, JTASessionContext context) {
this.transactionIdentifier = transactionIdentifier;
this.context = context;
}
@Override
public void beforeCompletion() {
}
@Override
public void afterCompletion(int i) {
context.currentSessionMap.remove( transactionIdentifier );
}
}
}