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Spring Framework example source code file (TransactionAwareConnectionFactoryProxy.java)

This example Spring Framework source code file (TransactionAwareConnectionFactoryProxy.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

closesuppressingsessioninvocationhandler, connection, jmsexception, object, queueconnection, queueconnection, queueconnectionfactory, queueconnectionfactory, reflection, session, string, topicconnection, topicconnection, topicconnectionfactory, topicconnectionfactory, util

The Spring Framework TransactionAwareConnectionFactoryProxy.java source code

/*
 * 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.jms.connection;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.JMSException;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.QueueSession;
import javax.jms.Session;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import javax.jms.TopicSession;
import javax.jms.TransactionInProgressException;

import org.springframework.util.Assert;

/**
 * Proxy for a target JMS {@link javax.jms.ConnectionFactory}, adding awareness of
 * Spring-managed transactions. Similar to a transactional JNDI ConnectionFactory
 * as provided by a J2EE server.
 *
 * <p>Messaging code that should remain unaware of Spring's JMS support can work
 * with this proxy to seamlessly participate in Spring-managed transactions.
 * Note that the transaction manager, for example {@link JmsTransactionManager},
 * still needs to work with the underlying ConnectionFactory, <i>not with
 * this proxy.
 *
 * <p>Make sure that TransactionAwareConnectionFactoryProxy is the outermost
 * ConnectionFactory of a chain of ConnectionFactory proxies/adapters.</b>
 * TransactionAwareConnectionFactoryProxy can delegate either directly to the
 * target factory or to some intermediary adapter like
 * {@link UserCredentialsConnectionFactoryAdapter}.
 *
 * <p>Delegates to {@link ConnectionFactoryUtils} for automatically participating
 * in thread-bound transactions, for example managed by {@link JmsTransactionManager}.
 * <code>createSession calls and close calls on returned Sessions
 * will behave properly within a transaction, that is, always work on the transactional
 * Session. If not within a transaction, normal ConnectionFactory behavior applies.
 *
 * <p>Note that transactional JMS Sessions will be registered on a per-Connection
 * basis. To share the same JMS Session across a transaction, make sure that you
 * operate on the same JMS Connection handle - either through reusing the handle
 * or through configuring a {@link SingleConnectionFactory} underneath.
 *
 * <p>Returned transactional Session proxies will implement the {@link SessionProxy}
 * interface to allow for access to the underlying target Session. This is only
 * intended for accessing vendor-specific Session API or for testing purposes
 * (e.g. to perform manual transaction control). For typical application purposes,
 * simply use the standard JMS Session interface.
 *
 * @author Juergen Hoeller
 * @since 2.0
 * @see UserCredentialsConnectionFactoryAdapter
 * @see SingleConnectionFactory
 */
public class TransactionAwareConnectionFactoryProxy
		implements ConnectionFactory, QueueConnectionFactory, TopicConnectionFactory {

	private boolean synchedLocalTransactionAllowed = false;

	private ConnectionFactory targetConnectionFactory;


	/**
	 * Create a new TransactionAwareConnectionFactoryProxy.
	 */
	public TransactionAwareConnectionFactoryProxy() {
	}

	/**
	 * Create a new TransactionAwareConnectionFactoryProxy.
	 * @param targetConnectionFactory the target ConnectionFactory
	 */
	public TransactionAwareConnectionFactoryProxy(ConnectionFactory targetConnectionFactory) {
		setTargetConnectionFactory(targetConnectionFactory);
	}


	/**
	 * Set the target ConnectionFactory that this ConnectionFactory should delegate to.
	 */
	public final void setTargetConnectionFactory(ConnectionFactory targetConnectionFactory) {
		Assert.notNull(targetConnectionFactory, "targetConnectionFactory must not be nul");
		this.targetConnectionFactory = targetConnectionFactory;
	}

	/**
	 * Return the target ConnectionFactory that this ConnectionFactory should delegate to.
	 */
	protected ConnectionFactory getTargetConnectionFactory() {
		return this.targetConnectionFactory;
	}

	/**
	 * Set whether to allow for a local JMS transaction that is synchronized with a
	 * Spring-managed transaction (where the main transaction might be a JDBC-based
	 * one for a specific DataSource, for example), with the JMS transaction committing
	 * right after the main transaction. If not allowed, the given ConnectionFactory
	 * needs to handle transaction enlistment underneath the covers.
	 * <p>Default is "false": If not within a managed transaction that encompasses
	 * the underlying JMS ConnectionFactory, standard Sessions will be returned.
	 * Turn this flag on to allow participation in any Spring-managed transaction,
	 * with a local JMS transaction synchronized with the main transaction.
	 */
	public void setSynchedLocalTransactionAllowed(boolean synchedLocalTransactionAllowed) {
		this.synchedLocalTransactionAllowed = synchedLocalTransactionAllowed;
	}

	/**
	 * Return whether to allow for a local JMS transaction that is synchronized
	 * with a Spring-managed transaction.
	 */
	protected boolean isSynchedLocalTransactionAllowed() {
		return this.synchedLocalTransactionAllowed;
	}


	public Connection createConnection() throws JMSException {
		Connection targetConnection = this.targetConnectionFactory.createConnection();
		return getTransactionAwareConnectionProxy(targetConnection);
	}

	public Connection createConnection(String username, String password) throws JMSException {
		Connection targetConnection = this.targetConnectionFactory.createConnection(username, password);
		return getTransactionAwareConnectionProxy(targetConnection);
	}

	public QueueConnection createQueueConnection() throws JMSException {
		if (!(this.targetConnectionFactory instanceof QueueConnectionFactory)) {
			throw new javax.jms.IllegalStateException("'targetConnectionFactory' is no QueueConnectionFactory");
		}
		QueueConnection targetConnection =
				((QueueConnectionFactory) this.targetConnectionFactory).createQueueConnection();
		return (QueueConnection) getTransactionAwareConnectionProxy(targetConnection);
	}

	public QueueConnection createQueueConnection(String username, String password) throws JMSException {
		if (!(this.targetConnectionFactory instanceof QueueConnectionFactory)) {
			throw new javax.jms.IllegalStateException("'targetConnectionFactory' is no QueueConnectionFactory");
		}
		QueueConnection targetConnection =
				((QueueConnectionFactory) this.targetConnectionFactory).createQueueConnection(username, password);
		return (QueueConnection) getTransactionAwareConnectionProxy(targetConnection);
	}

	public TopicConnection createTopicConnection() throws JMSException {
		if (!(this.targetConnectionFactory instanceof TopicConnectionFactory)) {
			throw new javax.jms.IllegalStateException("'targetConnectionFactory' is no TopicConnectionFactory");
		}
		TopicConnection targetConnection =
				((TopicConnectionFactory) this.targetConnectionFactory).createTopicConnection();
		return (TopicConnection) getTransactionAwareConnectionProxy(targetConnection);
	}

	public TopicConnection createTopicConnection(String username, String password) throws JMSException {
		if (!(this.targetConnectionFactory instanceof TopicConnectionFactory)) {
			throw new javax.jms.IllegalStateException("'targetConnectionFactory' is no TopicConnectionFactory");
		}
		TopicConnection targetConnection =
				((TopicConnectionFactory) this.targetConnectionFactory).createTopicConnection(username, password);
		return (TopicConnection) getTransactionAwareConnectionProxy(targetConnection);
	}


	/**
	 * Wrap the given Connection with a proxy that delegates every method call to it
	 * but handles Session lookup in a transaction-aware fashion.
	 * @param target the original Connection to wrap
	 * @return the wrapped Connection
	 */
	private Connection getTransactionAwareConnectionProxy(Connection target) {
		List classes = new ArrayList(3);
		classes.add(Connection.class);
		if (target instanceof QueueConnection) {
			classes.add(QueueConnection.class);
		}
		if (target instanceof TopicConnection) {
			classes.add(TopicConnection.class);
		}
		return (Connection) Proxy.newProxyInstance(
				getClass().getClassLoader(),
				(Class[]) classes.toArray(new Class[classes.size()]),
				new TransactionAwareConnectionInvocationHandler(target));
	}


	/**
	 * Invocation handler that exposes transactional Sessions for the underlying Connection.
	 */
	private class TransactionAwareConnectionInvocationHandler implements InvocationHandler {

		private final Connection target;

		public TransactionAwareConnectionInvocationHandler(Connection target) {
			this.target = target;
		}

		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
			// Invocation on ConnectionProxy interface coming in...

			if (Session.class.equals(method.getReturnType())) {
				Session session = ConnectionFactoryUtils.getTransactionalSession(
						getTargetConnectionFactory(), this.target, isSynchedLocalTransactionAllowed());
				if (session != null) {
					return getCloseSuppressingSessionProxy(session);
				}
			}
			else if (QueueSession.class.equals(method.getReturnType())) {
				QueueSession session = ConnectionFactoryUtils.getTransactionalQueueSession(
						(QueueConnectionFactory) getTargetConnectionFactory(), (QueueConnection) this.target,
						isSynchedLocalTransactionAllowed());
				if (session != null) {
					return getCloseSuppressingSessionProxy(session);
				}
			}
			else if (TopicSession.class.equals(method.getReturnType())) {
				TopicSession session = ConnectionFactoryUtils.getTransactionalTopicSession(
						(TopicConnectionFactory) getTargetConnectionFactory(), (TopicConnection) this.target,
						isSynchedLocalTransactionAllowed());
				if (session != null) {
					return getCloseSuppressingSessionProxy(session);
				}
			}
			else if (method.getName().equals("equals")) {
				// Only consider equal when proxies are identical.
				return (proxy == args[0] ? Boolean.TRUE : Boolean.FALSE);
			}
			else if (method.getName().equals("hashCode")) {
				// Use hashCode of Connection proxy.
				return new Integer(hashCode());
			}

			// Invoke method on target Connection.
			try {
				return method.invoke(this.target, args);
			}
			catch (InvocationTargetException ex) {
				throw ex.getTargetException();
			}
		}

		private Session getCloseSuppressingSessionProxy(Session target) {
			List classes = new ArrayList(3);
			classes.add(SessionProxy.class);
			if (target instanceof QueueSession) {
				classes.add(QueueSession.class);
			}
			if (target instanceof TopicSession) {
				classes.add(TopicSession.class);
			}
			return (Session) Proxy.newProxyInstance(
					SessionProxy.class.getClassLoader(),
					(Class[]) classes.toArray(new Class[classes.size()]),
					new CloseSuppressingSessionInvocationHandler(target));
		}
	}


	/**
	 * Invocation handler that suppresses close calls for a transactional JMS Session.
	 */
	private static class CloseSuppressingSessionInvocationHandler implements InvocationHandler {

		private final Session target;

		public CloseSuppressingSessionInvocationHandler(Session target) {
			this.target = target;
		}

		public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
			// Invocation on SessionProxy interface coming in...

			if (method.getName().equals("getTargetSession")) {
				// Handle getTargetSession method: return underlying Session.
				return this.target;
			}
			else if (method.getName().equals("equals")) {
				// Only consider equal when proxies are identical.
				return (proxy == args[0] ? Boolean.TRUE : Boolean.FALSE);
			}
			else if (method.getName().equals("hashCode")) {
				// Use hashCode of Connection proxy.
				return new Integer(hashCode());
			}
			else if (method.getName().equals("commit")) {
				throw new TransactionInProgressException("Commit call not allowed within a managed transaction");
			}
			else if (method.getName().equals("rollback")) {
				throw new TransactionInProgressException("Rollback call not allowed within a managed transaction");
			}
			else if (method.getName().equals("close")) {
				// Handle close method: not to be closed within a transaction.
				return null;
			}

			// Invoke method on target Session.
			try {
				return method.invoke(this.target, args);
			}
			catch (InvocationTargetException ex) {
				throw ex.getTargetException();
			}
		}
	}

}

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