/*
* JBoss, a division of Red Hat
* Copyright 2008, Red Hat Middleware, LLC, and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.gatein.wsrp.api.extensions;
import org.gatein.pc.api.invocation.PortletInvocation;
import org.gatein.pc.api.invocation.response.PortletInvocationResponse;
import org.gatein.wsrp.api.plugins.Plugins;
import org.gatein.wsrp.api.plugins.PluginsAccess;
/**
* A delegate that can be used to intercept PortletInvocations and PortletInvocationReponses before they are processed
* either by the Consumer or Producer. While this is particularly useful to be able to add and process WSRP Extensions
* that are outside of the WSRP specification, delegates could certainly be used to do more. However, since they have
* access to raw data from the portal's internal, one must be very careful about what's being done to the invocations
* and responses as a wrong operation could possibly have disastrous results on the portal's behavior. It is therefore
* <strong>extremely recommended</strong> (though not currently enforced) to treat the access to PortletInvocation and
* PortletInvocationResponse objects as <strong>read-only</strong>.
* <p/>
* On the Consumer side, the consumer InvocationHandlerDelegate can intercept the incoming PortletInvocation from the
* consumer portal before it is processed by the WSRP stack, i.e. before a WSRP request is sent to the remote producer.
* On the flip side, the response from the producer can be processed right after the WSRP stack is done with it but
* before it is processed by the consumer portal.
* <p/>
* On the Producer side, the producer InvocationHandlerDelegate can intercept the PortletInvocation that has been
* created as a translation of the incoming WSRP request before it is sent to the producer portal's portlet container.
* The response from the portlet container can then be processed before it is handled by the WSRP stack to be sent back
* to the Consumer.
*
* @author <a href="mailto:chris.laprun@jboss.com">Chris Laprun</a>
*/
public abstract class InvocationHandlerDelegate
{
private static InvocationHandlerDelegate consumerDelegate;
private static InvocationHandlerDelegate producerDelegate;
public static final String CONSUMER_DELEGATE_CLASSNAME = "org.gatein.wsrp.consumer.handlers.delegate";
public static final String PRODUCER_DELEGATE_CLASSNAME = "org.gatein.wsrp.producer.handlers.delegate";
static
{
final Plugins plugins = PluginsAccess.getPlugins();
consumerDelegate = createInstance(CONSUMER_DELEGATE_CLASSNAME, plugins);
producerDelegate = createInstance(PRODUCER_DELEGATE_CLASSNAME, plugins);
}
private static InvocationHandlerDelegate createInstance(String propertyName, Plugins plugins)
{
String delegateClassName = System.getProperty(propertyName);
if (delegateClassName != null && !delegateClassName.isEmpty())
{
return plugins.createPluginInstance(delegateClassName, InvocationHandlerDelegate.class);
}
else
{
return null;
}
}
/**
* Only public for testing purposes
*
* @param delegate
*/
public static synchronized void registerConsumerDelegate(InvocationHandlerDelegate delegate)
{
consumerDelegate = delegate;
}
/**
* Only public for testing purposes
*
* @param delegate
*/
public static synchronized void registerProducerDelegate(InvocationHandlerDelegate delegate)
{
producerDelegate = delegate;
}
/**
* Retrieves the delegate on the Consumer side.
*
* @return
*/
public static InvocationHandlerDelegate consumerDelegate()
{
return consumerDelegate;
}
/**
* Retrieves the delegate on the Producer side.
*
* @return
*/
public static InvocationHandlerDelegate producerDelegate()
{
return producerDelegate;
}
/**
* Method to process the specified PortletInvocation before it is handled by the rest of the WSRP invocation chain.
* See the class documentation for more details.
*
* @param invocation the PortletInvocation to process (recommended to consider as read-only, used to extract
* information from, not modify)
*/
public abstract void processInvocation(PortletInvocation invocation);
/**
* Method to process the specified PortletInvocationResponse before it is handled by the rest of the WSRP invocation
* chain. See the class documentation for more details.
*
* @param response the PortletInvocationResponse to process (recommended to consider as read-only, used to extract
* information from, not modify)
* @param invocation the PortletInvocation that caused the specified PortletInvocationResponse (recommended to
* consider as read-only, used to extract
* information from, not modify)
*/
public abstract void processInvocationResponse(PortletInvocationResponse response, PortletInvocation invocation);
}