/*
* Copyright 2002-2007 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.orm.hibernate3;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.hibernate.FlushMode;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.springframework.transaction.support.TransactionSynchronizationManager;
/**
* This interceptor binds a new Hibernate Session to the thread before a method
* call, closing and removing it afterwards in case of any method outcome.
* If there already is a pre-bound Session (e.g. from HibernateTransactionManager,
* or from a surrounding Hibernate-intercepted method), the interceptor simply
* participates in it.
*
* <p>Application code must retrieve a Hibernate Session via the
* <code>SessionFactoryUtils.getSession</code> method or - preferably -
* Hibernate's own <code>SessionFactory.getCurrentSession()</code> method, to be
* able to detect a thread-bound Session. Typically, the code will look like as follows:
*
* <pre>
* public void doSomeDataAccessAction() {
* Session session = this.sessionFactory.getCurrentSession();
* ...
* // No need to close the Session or translate exceptions!
* }</pre>
*
* Note that this interceptor automatically translates HibernateExceptions,
* via delegating to the <code>SessionFactoryUtils.convertHibernateAccessException</code>
* method that converts them to exceptions that are compatible with the
* <code>org.springframework.dao</code> exception hierarchy (like HibernateTemplate does).
* This can be turned off if the raw exceptions are preferred.
*
* <p>This class can be considered a declarative alternative to HibernateTemplate's
* callback approach. The advantages are:
* <ul>
* <li>no anonymous classes necessary for callback implementations;
* <li>the possibility to throw any application exceptions from within data access code.
* </ul>
*
* <p>The drawback is the dependency on interceptor configuration. However, note
* that this interceptor is usually <i>not</i> necessary in scenarios where the
* data access code always executes within transactions. A transaction will always
* have a thread-bound Session in the first place, so adding this interceptor to the
* configuration just adds value when fine-tuning Session settings like the flush mode
* - or when relying on exception translation.
*
* @author Juergen Hoeller
* @since 1.2
* @see org.hibernate.SessionFactory#getCurrentSession()
* @see HibernateTransactionManager
* @see HibernateTemplate
*/
public class HibernateInterceptor extends HibernateAccessor implements MethodInterceptor {
private boolean exceptionConversionEnabled = true;
/**
* Set whether to convert any HibernateException raised to a Spring DataAccessException,
* compatible with the <code>org.springframework.dao</code> exception hierarchy.
* <p>Default is "true". Turn this flag off to let the caller receive raw exceptions
* as-is, without any wrapping.
* @see org.springframework.dao.DataAccessException
*/
public void setExceptionConversionEnabled(boolean exceptionConversionEnabled) {
this.exceptionConversionEnabled = exceptionConversionEnabled;
}
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
Session session = getSession();
SessionHolder sessionHolder =
(SessionHolder) TransactionSynchronizationManager.getResource(getSessionFactory());
boolean existingTransaction = (sessionHolder != null && sessionHolder.containsSession(session));
if (existingTransaction) {
logger.debug("Found thread-bound Session for HibernateInterceptor");
}
else {
if (sessionHolder != null) {
sessionHolder.addSession(session);
}
else {
TransactionSynchronizationManager.bindResource(getSessionFactory(), new SessionHolder(session));
}
}
FlushMode previousFlushMode = null;
try {
previousFlushMode = applyFlushMode(session, existingTransaction);
enableFilters(session);
Object retVal = methodInvocation.proceed();
flushIfNecessary(session, existingTransaction);
return retVal;
}
catch (HibernateException ex) {
if (this.exceptionConversionEnabled) {
throw convertHibernateAccessException(ex);
}
else {
throw ex;
}
}
finally {
if (existingTransaction) {
logger.debug("Not closing pre-bound Hibernate Session after HibernateInterceptor");
disableFilters(session);
if (previousFlushMode != null) {
session.setFlushMode(previousFlushMode);
}
}
else {
SessionFactoryUtils.closeSessionOrRegisterDeferredClose(session, getSessionFactory());
if (sessionHolder == null || sessionHolder.doesNotHoldNonDefaultSession()) {
TransactionSynchronizationManager.unbindResource(getSessionFactory());
}
}
}
}
/**
* Return a Session for use by this interceptor.
* @see SessionFactoryUtils#getSession
*/
protected Session getSession() {
return SessionFactoryUtils.getSession(
getSessionFactory(), getEntityInterceptor(), getJdbcExceptionTranslator());
}
}
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