cachesynchronization.java

一个Java持久层类库

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC 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 Middleware LLC.
 *
 * 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.transaction;

import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.SystemException;
import javax.transaction.Transaction;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.hibernate.TransactionException;
import org.hibernate.jdbc.JDBCContext;
import org.hibernate.util.JTAHelper;

/**
 * A JTA transaction synch used to allow the {@link org.hibernate.Session} to know about transaction
 * events.
 *
 * @author Gavin King
 */
public final class CacheSynchronization implements Synchronization {

	private static final Logger log = LoggerFactory.getLogger(CacheSynchronization.class);

	private final TransactionFactory.Context ctx;
	private JDBCContext jdbcContext;
	private final Transaction transaction;
	private final org.hibernate.Transaction hibernateTransaction;

	public CacheSynchronization(
			TransactionFactory.Context ctx, 
			JDBCContext jdbcContext, 
			Transaction transaction, 
			org.hibernate.Transaction tx) {
		this.ctx = ctx;
		this.jdbcContext = jdbcContext;
		this.transaction = transaction;
		this.hibernateTransaction = tx;
	}

	/**
	 * {@inheritDoc}
	 */
	public void beforeCompletion() {
		log.trace("transaction before completion callback");

		boolean flush;
		try {
			flush = !ctx.isFlushModeNever() &&
			        ctx.isFlushBeforeCompletionEnabled() && 
			        !JTAHelper.isRollback( transaction.getStatus() ); 
					//actually, this last test is probably unnecessary, since 
					//beforeCompletion() doesn't get called during rollback
		}
		catch (SystemException se) {
			log.error("could not determine transaction status", se);
			setRollbackOnly();
			throw new TransactionException("could not determine transaction status in beforeCompletion()", se);
		}
		
		try {
			if (flush) {
				log.trace("automatically flushing session");
				ctx.managedFlush();
			}
		}
		catch (RuntimeException re) {
			setRollbackOnly();
			throw re;
		}
		finally {
			jdbcContext.beforeTransactionCompletion(hibernateTransaction);
		}
	}

	private void setRollbackOnly() {
		try {
			transaction.setRollbackOnly();
		}
		catch (SystemException se) {
			log.error("could not set transaction to rollback only", se);
		}
	}

	/**
	 * {@inheritDoc}
	 */
	public void afterCompletion(int status) {
		if ( log.isTraceEnabled() ) {
			log.trace("transaction after completion callback, status: " + status);
		}
		try {
			jdbcContext.afterTransactionCompletion(status==Status.STATUS_COMMITTED, hibernateTransaction);
		}
		finally {
			if ( ctx.shouldAutoClose() && !ctx.isClosed() ) {
				log.trace("automatically closing session");
				ctx.managedClose();
			}
		}
	}
	
	/**
	 * {@inheritDoc}
	 */
	public String toString() {
		return CacheSynchronization.class.getName();
	}

}