/*
============================================================================
The Apache Software License, Version 1.1
============================================================================
Copyright (C) 1999-2003 The Apache Software Foundation. All rights reserved.
Redistribution and use in source and binary forms, with or without modifica-
tion, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. The end-user documentation included with the redistribution, if any, must
include the following acknowledgment: "This product includes software
developed by the Apache Software Foundation (http://www.apache.org/)."
Alternately, this acknowledgment may appear in the software itself, if
and wherever such third-party acknowledgments normally appear.
4. The names "Apache Cocoon" and "Apache Software Foundation" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
apache@apache.org.
5. Products derived from this software may not be called "Apache", nor may
"Apache" appear in their name, without prior written permission of the
Apache Software Foundation.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
APACHE SOFTWARE FOUNDATION OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLU-
DING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This software consists of voluntary contributions made by many individuals
on behalf of the Apache Software Foundation and was originally created by
Stefano Mazzocchi <stefano@apache.org>. For more information on the Apache
Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.cocoon.components.jms;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.naming.NamingException;
import org.apache.avalon.framework.CascadingException;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.parameters.ParameterException;
import org.apache.avalon.framework.parameters.Parameterizable;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.avalon.framework.thread.ThreadSafe;
import org.apache.cocoon.caching.EventAware;
import org.apache.cocoon.caching.validity.Event;
import org.apache.cocoon.caching.validity.NamedEvent;
/**
* JMS listener will notify an {@link org.apache.cocoon.caching.EventAware} component
* of external events. This could be used for example to do external cache invalidation.
* Configuration parameters default to <a href="http://openjms.sf.net">OpenJMS</a> demo
* installation on localhost using "topic1".
*
* <p>Parameters:</p>
* <table>
* <tbody>
* <tr><td>connection </td><td>(required, no default)</td></tr>
* <tr><td>component </td><td>(required, no default)</td></tr>
* <tr><td>message-selector</td><td>("")</td></tr>
* </tbody>
* </table>
*
* @version CVS $Id: JMSEventListener.java,v 1.6 2004/01/05 17:14:44 unico Exp $
* @author <a href="mailto:chaul@informatik.tu-darmstadt.de">chaul</a>
*/
public class JMSEventListener
extends AbstractLogEnabled
implements Serviceable, Parameterizable, MessageListener, Initializable, Disposable, ThreadSafe {
protected String selector = "";
protected ServiceManager manager;
protected String serviceName = null;
protected EventAware service = null;
protected String connectionName = null;
protected JMSConnection connection = null;
/*
* @see org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager)
*/
public void service(ServiceManager manager) throws ServiceException {
this.manager = manager;
}
/*
* @see org.apache.avalon.framework.parameters.Parameterizable#parameterize(org.apache.avalon.framework.parameters.Parameters)
*/
public void parameterize(Parameters parameters) throws ParameterException {
this.connectionName = parameters.getParameter("connection");
this.serviceName = parameters.getParameter("component");
this.selector = parameters.getParameter("message-selector", this.selector);
}
public void initialize() {
try {
this.connection = (JMSConnection) this.manager.lookup(JMSConnection.ROLE+"/"+this.connectionName);
this.connection.registerListener(this, this.selector);
} catch (ServiceException e) {
if (getLogger().isWarnEnabled()) {
getLogger().warn("Could not obtain JMSConnection");
}
} catch (JMSException e) {
if (getLogger().isWarnEnabled()) {
getLogger().warn("Could not obtain JMSConnection");
}
} catch (NamingException e) {
if (getLogger().isWarnEnabled()) {
getLogger().warn("Could not obtain JMSConnection");
}
} catch (CascadingException e) {
if (getLogger().isWarnEnabled()) {
getLogger().warn("Could not obtain JMSConnection");
}
}
}
/* (non-Javadoc)
* @see org.apache.avalon.framework.activity.Disposable#dispose()
*/
public void dispose() {
if (this.manager != null){
this.manager.release(connection);
this.manager.release(service);
}
}
/*
* @see javax.jms.MessageListener#onMessage(javax.jms.Message)
*/
public synchronized void onMessage(Message message) {
EventAware service = this.service;
try {
if (service == null) {
service = (EventAware) this.manager.lookup(this.serviceName);
}
Event event = this.convertMessage(message);
if (this.getLogger().isInfoEnabled())
this.getLogger().info(
"Notifying "
+ this.serviceName
+ " of "
+ event);
service.processEvent(event);
} catch (ServiceException e) {
if (this.getLogger().isErrorEnabled()) {
this.getLogger().error(
"Could not obtain " + this.serviceName + " from component manager.",
e);
}
} finally {
if (service instanceof ThreadSafe) {
this.service = service;
} else {
this.manager.release(service);
}
}
}
/**
* Convert the message contents to a cache event. The default implementation
* assumes that the message contains the trigger name, a '|', and a table name.
* It extracts the tablename and creates a NamedEvent with it.
* Override this method to provide your own message to event mappings.
*
* @param message the JMS message.
* @return the cache event.
*/
protected Event convertMessage(Message message) {
String name = message.toString();
int pos = name.indexOf('|');
return new NamedEvent(name.substring(pos + 1));
}
}