/*
* Copyright 2002-2009 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.ExceptionListener;
import javax.jms.JMSException;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.Session;
import javax.jms.TopicConnection;
import javax.jms.TopicConnectionFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;
/**
* A JMS ConnectionFactory adapter that returns the same Connection
* from all {@link #createConnection()} calls, and ignores calls to
* {@link javax.jms.Connection#close()}. According to the JMS Connection
* model, this is perfectly thread-safe (in contrast to e.g. JDBC). The
* shared Connection can be automatically recovered in case of an Exception.
*
* <p>You can either pass in a specific JMS Connection directly or let this
* factory lazily create a Connection via a given target ConnectionFactory.
* This factory generally works with JMS 1.1 as well as the JMS 1.0.2 API.
*
* <p>Note that when using the JMS 1.0.2 API, this ConnectionFactory will switch
* into queue/topic mode according to the JMS API methods used at runtime:
* <code>createQueueConnection</code> and <code>createTopicConnection</code> will
* lead to queue/topic mode, respectively; generic <code>createConnection</code>
* calls will lead to a JMS 1.1 connection which is able to serve both modes.
*
* <p>Useful for testing and standalone environments in order to keep using the
* same Connection for multiple {@link org.springframework.jms.core.JmsTemplate}
* calls, without having a pooling ConnectionFactory underneath. This may span
* any number of transactions, even concurrently executing transactions.
*
* <p>Note that Spring's message listener containers support the use of
* a shared Connection within each listener container instance. Using
* SingleConnectionFactory in combination only really makes sense for
* sharing a single JMS Connection <i>across multiple listener containers</i>.
*
* @author Juergen Hoeller
* @author Mark Pollack
* @since 1.1
* @see org.springframework.jms.core.JmsTemplate
* @see org.springframework.jms.listener.SimpleMessageListenerContainer
* @see org.springframework.jms.listener.DefaultMessageListenerContainer#setCacheLevel
*/
public class SingleConnectionFactory
implements ConnectionFactory, QueueConnectionFactory, TopicConnectionFactory, ExceptionListener,
InitializingBean, DisposableBean {
protected final Log logger = LogFactory.getLog(getClass());
private ConnectionFactory targetConnectionFactory;
private String clientId;
private ExceptionListener exceptionListener;
private boolean reconnectOnException = false;
/** Wrapped Connection */
private Connection target;
/** Proxy Connection */
private Connection connection;
/** A hint whether to create a queue or topic connection */
private Boolean pubSubMode;
/** Whether the shared Connection has been started */
private boolean started = false;
/** Synchronization monitor for the shared Connection */
private final Object connectionMonitor = new Object();
/**
* Create a new SingleConnectionFactory for bean-style usage.
* @see #setTargetConnectionFactory
*/
public SingleConnectionFactory() {
}
/**
* Create a new SingleConnectionFactory that always returns the given Connection.
* @param target the single Connection
*/
public SingleConnectionFactory(Connection target) {
Assert.notNull(target, "Target Connection must not be null");
this.target = target;
this.connection = getSharedConnectionProxy(target);
}
/**
* Create a new SingleConnectionFactory that always returns a single
* Connection that it will lazily create via the given target
* ConnectionFactory.
* @param targetConnectionFactory the target ConnectionFactory
*/
public SingleConnectionFactory(ConnectionFactory targetConnectionFactory) {
Assert.notNull(targetConnectionFactory, "Target ConnectionFactory must not be null");
this.targetConnectionFactory = targetConnectionFactory;
}
/**
* Set the target ConnectionFactory which will be used to lazily
* create a single Connection.
*/
public void setTargetConnectionFactory(ConnectionFactory targetConnectionFactory) {
this.targetConnectionFactory = targetConnectionFactory;
}
/**
* Return the target ConnectionFactory which will be used to lazily
* create a single Connection, if any.
*/
public ConnectionFactory getTargetConnectionFactory() {
return this.targetConnectionFactory;
}
/**
* Specify a JMS client ID for the single Connection created and exposed
* by this ConnectionFactory.
* <p>Note that client IDs need to be unique among all active Connections
* of the underlying JMS provider. Furthermore, a client ID can only be
* assigned if the original ConnectionFactory hasn't already assigned one.
* @see javax.jms.Connection#setClientID
* @see #setTargetConnectionFactory
*/
public void setClientId(String clientId) {
this.clientId = clientId;
}
/**
* Return a JMS client ID for the single Connection created and exposed
* by this ConnectionFactory, if any.
*/
protected String getClientId() {
return this.clientId;
}
/**
* Specify an JMS ExceptionListener implementation that should be
* registered with with the single Connection created by this factory.
* @see #setReconnectOnException
*/
public void setExceptionListener(ExceptionListener exceptionListener) {
this.exceptionListener = exceptionListener;
}
/**
* Return the JMS ExceptionListener implementation that should be registered
* with with the single Connection created by this factory, if any.
*/
protected ExceptionListener getExceptionListener() {
return this.exceptionListener;
}
/**
* Specify whether the single Connection should be reset (to be subsequently renewed)
* when a JMSException is reported by the underlying Connection.
* <p>Default is "false". Switch this to "true" to automatically trigger
* recovery based on your JMS provider's exception notifications.
* <p>Internally, this will lead to a special JMS ExceptionListener
* (this SingleConnectionFactory itself) being registered with the
* underlying Connection. This can also be combined with a
* user-specified ExceptionListener, if desired.
* @see #setExceptionListener
*/
public void setReconnectOnException(boolean reconnectOnException) {
this.reconnectOnException = reconnectOnException;
}
/**
* Return whether the single Connection should be renewed when
* a JMSException is reported by the underlying Connection.
*/
protected boolean isReconnectOnException() {
return this.reconnectOnException;
}
/**
* Make sure a Connection or ConnectionFactory has been set.
*/
public void afterPropertiesSet() {
if (this.connection == null && getTargetConnectionFactory() == null) {
throw new IllegalArgumentException("Connection or 'targetConnectionFactory' is required");
}
}
public Connection createConnection() throws JMSException {
synchronized (this.connectionMonitor) {
if (this.connection == null) {
initConnection();
}
return this.connection;
}
}
public Connection createConnection(String username, String password) throws JMSException {
throw new javax.jms.IllegalStateException(
"SingleConnectionFactory does not support custom username and password");
}
public QueueConnection createQueueConnection() throws JMSException {
Connection con;
synchronized (this.connectionMonitor) {
this.pubSubMode = Boolean.FALSE;
con = createConnection();
}
if (!(con instanceof QueueConnection)) {
throw new javax.jms.IllegalStateException(
"This SingleConnectionFactory does not hold a QueueConnection but rather: " + con);
}
return ((QueueConnection) con);
}
public QueueConnection createQueueConnection(String username, String password) throws JMSException {
throw new javax.jms.IllegalStateException(
"SingleConnectionFactory does not support custom username and password");
}
public TopicConnection createTopicConnection() throws JMSException {
Connection con;
synchronized (this.connectionMonitor) {
this.pubSubMode = Boolean.TRUE;
con = createConnection();
}
if (!(con instanceof TopicConnection)) {
throw new javax.jms.IllegalStateException(
"This SingleConnectionFactory does not hold a TopicConnection but rather: " + con);
}
return ((TopicConnection) con);
}
public TopicConnection createTopicConnection(String username, String password) throws JMSException {
throw new javax.jms.IllegalStateException(
"SingleConnectionFactory does not support custom username and password");
}
/**
* Initialize the underlying shared Connection.
* <p>Closes and reinitializes the Connection if an underlying
* Connection is present already.
* @throws javax.jms.JMSException if thrown by JMS API methods
*/
public void initConnection() throws JMSException {
if (getTargetConnectionFactory() == null) {
throw new IllegalStateException(
"'targetConnectionFactory' is required for lazily initializing a Connection");
}
synchronized (this.connectionMonitor) {
if (this.target != null) {
closeConnection(this.target);
}
this.target = doCreateConnection();
prepareConnection(this.target);
if (logger.isInfoEnabled()) {
logger.info("Established shared JMS Connection: " + this.target);
}
this.connection = getSharedConnectionProxy(this.target);
}
}
/**
* Exception listener callback that renews the underlying single Connection.
*/
public void onException(JMSException ex) {
logger.warn("Encountered a JMSException - resetting the underlying JMS Connection", ex);
resetConnection();
}
/**
* Close the underlying shared connection.
* The provider of this ConnectionFactory needs to care for proper shutdown.
* <p>As this bean implements DisposableBean, a bean factory will
* automatically invoke this on destruction of its cached singletons.
*/
public void destroy() {
resetConnection();
}
/**
* Reset the underlying shared Connection, to be reinitialized on next access.
*/
public void resetConnection() {
synchronized (this.connectionMonitor) {
if (this.target != null) {
closeConnection(this.target);
}
this.target = null;
this.connection = null;
}
}
/**
* Create a JMS Connection via this template's ConnectionFactory.
* @return the new JMS Connection
* @throws javax.jms.JMSException if thrown by JMS API methods
*/
protected Connection doCreateConnection() throws JMSException {
ConnectionFactory cf = getTargetConnectionFactory();
if (Boolean.FALSE.equals(this.pubSubMode) && cf instanceof QueueConnectionFactory) {
return ((QueueConnectionFactory) cf).createQueueConnection();
}
else if (Boolean.TRUE.equals(this.pubSubMode) && cf instanceof TopicConnectionFactory) {
return ((TopicConnectionFactory) cf).createTopicConnection();
}
else {
return getTargetConnectionFactory().createConnection();
}
}
/**
* Prepare the given Connection before it is exposed.
* <p>The default implementation applies ExceptionListener and client id.
* Can be overridden in subclasses.
* @param con the Connection to prepare
* @throws JMSException if thrown by JMS API methods
* @see #setExceptionListener
* @see #setReconnectOnException
*/
protected void prepareConnection(Connection con) throws JMSException {
if (getClientId() != null) {
con.setClientID(getClientId());
}
if (getExceptionListener() != null || isReconnectOnException()) {
ExceptionListener listenerToUse = getExceptionListener();
if (isReconnectOnException()) {
listenerToUse = new InternalChainedExceptionListener(this, listenerToUse);
}
con.setExceptionListener(listenerToUse);
}
}
/**
* Template method for obtaining a (potentially cached) Session.
* <p>The default implementation always returns <code>null</code>.
* Subclasses may override this for exposing specific Session handles,
* possibly delegating to {@link #createSession} for the creation of raw
* Session objects that will then get wrapped and returned from here.
* @param con the JMS Connection to operate on
* @param mode the Session acknowledgement mode
* (<code>Session.TRANSACTED</code> or one of the common modes)
* @return the Session to use, or <code>null</code> to indicate
* creation of a raw standard Session
* @throws JMSException if thrown by the JMS API
*/
protected Session getSession(Connection con, Integer mode) throws JMSException {
return null;
}
/**
* Create a default Session for this ConnectionFactory,
* adaptign to JMS 1.0.2 style queue/topic mode if necessary.
* @param con the JMS Connection to operate on
* @param mode the Session acknowledgement mode
* (<code>Session.TRANSACTED</code> or one of the common modes)
* @return the newly created Session
* @throws JMSException if thrown by the JMS API
*/
protected Session createSession(Connection con, Integer mode) throws JMSException {
// Determine JMS API arguments...
boolean transacted = (mode == Session.SESSION_TRANSACTED);
int ackMode = (transacted ? Session.AUTO_ACKNOWLEDGE : mode);
// Now actually call the appropriate JMS factory method...
if (Boolean.FALSE.equals(this.pubSubMode) && con instanceof QueueConnection) {
return ((QueueConnection) con).createQueueSession(transacted, ackMode);
}
else if (Boolean.TRUE.equals(this.pubSubMode) && con instanceof TopicConnection) {
return ((TopicConnection) con).createTopicSession(transacted, ackMode);
}
else {
return con.createSession(transacted, ackMode);
}
}
/**
* Close the given Connection.
* @param con the Connection to close
*/
protected void closeConnection(Connection con) {
if (logger.isDebugEnabled()) {
logger.debug("Closing shared JMS Connection: " + this.target);
}
try {
try {
if (this.started) {
this.started = false;
con.stop();
}
}
finally {
con.close();
}
}
catch (javax.jms.IllegalStateException ex) {
logger.debug("Ignoring Connection state exception - assuming already closed: " + ex);
}
catch (Throwable ex) {
logger.debug("Could not close shared JMS Connection", ex);
}
}
/**
* Wrap the given Connection with a proxy that delegates every method call to it
* but suppresses close calls. This is useful for allowing application code to
* handle a special framework Connection just like an ordinary Connection from a
* JMS ConnectionFactory.
* @param target the original Connection to wrap
* @return the wrapped Connection
*/
protected Connection getSharedConnectionProxy(Connection target) {
List<Class> classes = new ArrayList<Class>(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(
Connection.class.getClassLoader(),
classes.toArray(new Class[classes.size()]),
new SharedConnectionInvocationHandler(target));
}
/**
* Invocation handler for a cached JMS Connection proxy.
*/
private class SharedConnectionInvocationHandler implements InvocationHandler {
private final Connection target;
public SharedConnectionInvocationHandler(Connection target) {
this.target = target;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (method.getName().equals("equals")) {
// Only consider equal when proxies are identical.
return (proxy == args[0]);
}
else if (method.getName().equals("hashCode")) {
// Use hashCode of Connection proxy.
return System.identityHashCode(proxy);
}
else if (method.getName().equals("toString")) {
return "Shared JMS Connection: " + this.target;
}
else if (method.getName().equals("setClientID")) {
// Handle setClientID method: throw exception if not compatible.
String currentClientId = this.target.getClientID();
if (currentClientId != null && currentClientId.equals(args[0])) {
return null;
}
else {
throw new javax.jms.IllegalStateException(
"setClientID call not supported on proxy for shared Connection. " +
"Set the 'clientId' property on the SingleConnectionFactory instead.");
}
}
else if (method.getName().equals("setExceptionListener")) {
// Handle setExceptionListener method: add to the chain.
ExceptionListener currentExceptionListener = this.target.getExceptionListener();
if (currentExceptionListener instanceof InternalChainedExceptionListener && args[0] != null) {
((InternalChainedExceptionListener) currentExceptionListener).addDelegate((ExceptionListener) args[0]);
return null;
}
else {
throw new javax.jms.IllegalStateException(
"setExceptionListener call not supported on proxy for shared Connection. " +
"Set the 'exceptionListener' property on the SingleConnectionFactory instead. " +
"Alternatively, activate SingleConnectionFactory's 'reconnectOnException' feature, " +
"which will allow for registering further ExceptionListeners to the recovery chain.");
}
}
else if (method.getName().equals("start")) {
// Handle start method: track started state.
synchronized (connectionMonitor) {
if (!started) {
this.target.start();
started = true;
}
}
return null;
}
else if (method.getName().equals("stop")) {
// Handle stop method: don't pass the call on.
return null;
}
else if (method.getName().equals("close")) {
// Handle close method: don't pass the call on.
return null;
}
else if (method.getName().equals("createSession") || method.getName().equals("createQueueSession") ||
method.getName().equals("createTopicSession")) {
boolean transacted = (Boolean) args[0];
Integer ackMode = (Integer) args[1];
Integer mode = (transacted ? Session.SESSION_TRANSACTED : ackMode);
Session session = getSession(this.target, mode);
if (session != null) {
if (!method.getReturnType().isInstance(session)) {
String msg = "JMS Session does not implement specific domain: " + session;
try {
session.close();
}
catch (Throwable ex) {
logger.trace("Failed to close newly obtained JMS Session", ex);
}
throw new javax.jms.IllegalStateException(msg);
}
return session;
}
}
try {
Object retVal = method.invoke(this.target, args);
if (method.getName().equals("getExceptionListener") && retVal instanceof InternalChainedExceptionListener) {
// Handle getExceptionListener method: hide internal chain.
InternalChainedExceptionListener listener = (InternalChainedExceptionListener) retVal;
return listener.getUserListener();
}
else {
return retVal;
}
}
catch (InvocationTargetException ex) {
throw ex.getTargetException();
}
}
}
/**
* Internal chained ExceptionListener for handling the internal recovery listener
* in combination with a user-specified listener.
*/
private static class InternalChainedExceptionListener extends ChainedExceptionListener {
private ExceptionListener userListener;
public InternalChainedExceptionListener(ExceptionListener internalListener, ExceptionListener userListener) {
addDelegate(internalListener);
if (userListener != null) {
addDelegate(userListener);
this.userListener = userListener;
}
}
public ExceptionListener getUserListener() {
return this.userListener;
}
}
}
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