/*
* Copyright 2002-2006 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.toplink;
import oracle.toplink.exceptions.TopLinkException;
import oracle.toplink.sessions.Session;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.transaction.support.TransactionSynchronizationManager;
/**
* This interceptor binds a new TopLink 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 TopLinkTransactionManager,
* or from a surrounding TopLink-intercepted method), the interceptor simply
* takes part in it.
*
* <p>Application code must retrieve a TopLink Session via the
* <code>SessionFactoryUtils.getSession</code> method or - preferably -
* TopLink's own <code>Session.getActiveSession()</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.serverSession.getActiveSession();
* ...
* }</pre>
*
* Note that this interceptor automatically translates TopLinkExceptions,
* via delegating to the <code>SessionFactoryUtils.convertTopLikAccessException</code>
* method that converts them to exceptions that are compatible with the
* <code>org.springframework.dao</code> exception hierarchy (like TopLinkTemplate does).
* This can be turned off if the raw exceptions are preferred.
*
* <p>This class can be considered a declarative alternative to TopLinkTemplate'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 potentially executing outside of transactions
* and/or when relying on exception translation.
*
* @author Juergen Hoeller
* @since 1.2
*/
public class TopLinkInterceptor extends TopLinkAccessor implements MethodInterceptor {
private boolean exceptionConversionEnabled = true;
/**
* Set whether to convert any TopLinkException 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 {
boolean existingTransaction = false;
Session session = SessionFactoryUtils.getSession(getSessionFactory(), true);
if (TransactionSynchronizationManager.hasResource(getSessionFactory())) {
logger.debug("Found thread-bound Session for TopLink interceptor");
existingTransaction = true;
}
else {
logger.debug("Using new Session for TopLink interceptor");
TransactionSynchronizationManager.bindResource(getSessionFactory(), new SessionHolder(session));
}
try {
return methodInvocation.proceed();
}
catch (TopLinkException ex) {
if (this.exceptionConversionEnabled) {
throw convertTopLinkAccessException(ex);
}
else {
throw ex;
}
}
finally {
if (existingTransaction) {
logger.debug("Not closing pre-bound TopLink Session after interceptor");
}
else {
TransactionSynchronizationManager.unbindResource(getSessionFactory());
SessionFactoryUtils.releaseSession(session, getSessionFactory());
}
}
}
}