Spring Framework example source code file (TopLinkInterceptor.java)

This example Spring Framework source code file (TopLinkInterceptor.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 - Spring Framework tags/keywords

found, methodinterceptor, not, object, object, session, session, sessionholder, toplink, toplink, toplinkaccessor, toplinkinterceptor, toplinkinterceptor, using

The Spring Framework TopLinkInterceptor.java source code

/*
 * 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 method or - preferably -
 * TopLink's own <code>Session.getActiveSession() 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
 * method that converts them to exceptions that are compatible with the
 * <code>org.springframework.dao 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 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 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());
			}
		}
	}

}