Hibernate example source code file (JTASessionContext.java)

This example Hibernate source code file (JTASessionContext.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Hibernate tags/keywords

cleanupsynch, cleanupsynch, hibernateexception, hibernateexception, jta, jtasessioncontext, jtasessioncontext, object, session, session, synchronization, throwable, transaction, transactionmanager, unable, util

The Hibernate JTASessionContext.java source code

/*
 * 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 javax.transaction.Synchronization;
import javax.transaction.Transaction;
import javax.transaction.TransactionManager;
import java.util.Hashtable;
import java.util.Map;

import org.jboss.logging.Logger;

import org.hibernate.ConnectionReleaseMode;
import org.hibernate.HibernateException;
import org.hibernate.context.spi.CurrentSessionContext;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.internal.CoreMessageLogger;
import org.hibernate.Session;
import org.hibernate.engine.transaction.internal.jta.JtaStatusHelper;
import org.hibernate.service.jta.platform.spi.JtaPlatform;

/**
 * An implementation of {@link 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.
 * <p/>
 * 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 implements CurrentSessionContext {
    private static final CoreMessageLogger LOG = Logger.getMessageLogger(CoreMessageLogger.class, JTASessionContext.class.getName());

	protected final SessionFactoryImplementor factory;
	private transient Map currentSessionMap = new Hashtable();

	public JTASessionContext(SessionFactoryImplementor factory) {
		this.factory = 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 = ( Session ) 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 );
		}

		return currentSession;
	}

	/**
	 * Builds a {@link CleanupSynch} 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 CleanupSynch buildCleanupSynch(Object transactionIdentifier) {
		return new CleanupSynch( transactionIdentifier, this );
	}

	/**
	 * Strictly provided for subclassing purposes; specifically to allow long-session
	 * support.
	 * <p/>
	 * This implementation always just opens a new session.
	 *
	 * @return the built or (re)obtained session.
	 */
	protected Session buildOrObtainSession() {
		return factory.withOptions()
				.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 synch used for cleanup of the internal session map.
	 */
	protected static class CleanupSynch implements Synchronization {
		private Object transactionIdentifier;
		private JTASessionContext context;

		public CleanupSynch(Object transactionIdentifier, JTASessionContext context) {
			this.transactionIdentifier = transactionIdentifier;
			this.context = context;
		}

		/**
		 * {@inheritDoc}
		 */
		public void beforeCompletion() {
		}

		/**
		 * {@inheritDoc}
		 */
		public void afterCompletion(int i) {
			context.currentSessionMap.remove( transactionIdentifier );
		}
	}
}