/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.felix.http.proxy;
import java.util.EventListener;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;
import org.osgi.framework.Filter;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
/**
* The <code>ProxyListener</code> implements a Servlet API listener for HTTP
* Session related events. These events are provided by the servlet container
* and forwarded to the event dispatcher.
*
* @since 2.1.0
*/
public class ProxyListener implements HttpSessionAttributeListener, HttpSessionListener, ServletContextListener
{
private ServletContext servletContext;
private ServiceTracker eventDispatcherTracker;
private HttpSessionListener sessionDispatcher;
private HttpSessionAttributeListener attributeDispatcher;
// ---------- ServletContextListener
public void contextInitialized(final ServletContextEvent sce)
{
this.servletContext = sce.getServletContext();
}
public void contextDestroyed(final ServletContextEvent sce)
{
if (this.eventDispatcherTracker != null)
{
this.eventDispatcherTracker.close();
this.eventDispatcherTracker = null;
}
this.servletContext = null;
}
// ---------- HttpSessionListener
public void sessionCreated(final HttpSessionEvent se)
{
final HttpSessionListener sessionDispatcher = getSessionDispatcher();
if (sessionDispatcher != null)
{
sessionDispatcher.sessionCreated(se);
}
}
public void sessionDestroyed(final HttpSessionEvent se)
{
final HttpSessionListener sessionDispatcher = getSessionDispatcher();
if (sessionDispatcher != null)
{
sessionDispatcher.sessionDestroyed(se);
}
}
// ---------- HttpSessionAttributeListener
public void attributeAdded(final HttpSessionBindingEvent se)
{
final HttpSessionAttributeListener attributeDispatcher = getAttributeDispatcher();
if (attributeDispatcher != null)
{
attributeDispatcher.attributeAdded(se);
}
}
public void attributeRemoved(final HttpSessionBindingEvent se)
{
final HttpSessionAttributeListener attributeDispatcher = getAttributeDispatcher();
if (attributeDispatcher != null)
{
attributeDispatcher.attributeRemoved(se);
}
}
public void attributeReplaced(final HttpSessionBindingEvent se)
{
final HttpSessionAttributeListener attributeDispatcher = getAttributeDispatcher();
if (attributeDispatcher != null)
{
attributeDispatcher.attributeReplaced(se);
}
}
// ---------- internal
private Object getDispatcher()
{
if (this.eventDispatcherTracker == null)
{
// the bundle context may or may not be already provided;
// if not we cannot access the dispatcher yet
Object bundleContextAttr = this.servletContext.getAttribute(BundleContext.class.getName());
if (!(bundleContextAttr instanceof BundleContext))
{
return null;
}
try
{
BundleContext bundleContext = (BundleContext) bundleContextAttr;
Filter filter = createFilter(bundleContext, null);
this.eventDispatcherTracker = new ServiceTracker(bundleContext, filter, null)
{
public void removedService(ServiceReference reference, Object service)
{
ProxyListener.this.sessionDispatcher = null;
ProxyListener.this.attributeDispatcher = null;
super.removedService(reference, service);
}
};
this.eventDispatcherTracker.open();
}
catch (InvalidSyntaxException e)
{
// not expected for our simple filter
}
}
return this.eventDispatcherTracker.getService();
}
private HttpSessionListener getSessionDispatcher()
{
if (this.sessionDispatcher == null)
{
final Object dispatcher = getDispatcher();
if (dispatcher instanceof HttpSessionListener)
{
this.sessionDispatcher = (HttpSessionListener) dispatcher;
}
}
return this.sessionDispatcher;
}
private HttpSessionAttributeListener getAttributeDispatcher()
{
if (this.attributeDispatcher == null)
{
final Object dispatcher = getDispatcher();
if (dispatcher instanceof HttpSessionAttributeListener)
{
this.attributeDispatcher = (HttpSessionAttributeListener) dispatcher;
}
}
return this.attributeDispatcher;
}
private static Filter createFilter(BundleContext context, String filter) throws InvalidSyntaxException
{
StringBuffer str = new StringBuffer();
str.append("(&(").append(Constants.OBJECTCLASS).append("=");
str.append(EventListener.class.getName()).append(")");
str.append(filter != null ? filter : DispatcherTracker.DEFAULT_FILTER).append(")");
return context.createFilter(str.toString());
}
}