/*
* Copyright 2005 Joe Walker
*
* 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.directwebremoting.servlet;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.directwebremoting.Container;
import org.directwebremoting.WebContextFactory.WebContextBuilder;
/**
* A Servlet Filter that can be used with other web frameworks to allow use of
* WebContextFactory. Any servlet threads that have their request URL mapped
* through a DwrWebContextFilter will have a WebContext available to them.
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class DwrWebContextFilter implements Filter
{
/* (non-Javadoc)
* @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
*/
public void init(FilterConfig newFilterConfig) throws ServletException
{
filterConfig = newFilterConfig;
}
/* (non-Javadoc)
* @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException
{
ServletContext servletContext = filterConfig.getServletContext();
Container container = (Container) servletContext.getAttribute(Container.class.getName());
if (container == null)
{
log.error("DwrWebContextFilter can not find ServletContext attribute for the DWR Container. Is DwrServlet configured in this web-application?");
}
ServletConfig servletConfig = (ServletConfig) servletContext.getAttribute(ServletConfig.class.getName());
if (servletConfig == null)
{
log.error("DwrWebContextFilter can not find ServletContext attribute for the ServletConfig.");
}
WebContextBuilder webContextBuilder = (WebContextBuilder) servletContext.getAttribute(WebContextBuilder.class.getName());
if (webContextBuilder == null)
{
log.error("DwrWebContextFilter can not find ServletContext attribute for the WebContextBuilder. WebContext will not be available.");
}
else
{
try
{
webContextBuilder.engageThread(container, (HttpServletRequest) request, (HttpServletResponse) response);
chain.doFilter(request, response);
}
finally
{
webContextBuilder.disengageThread();
}
}
}
/* (non-Javadoc)
* @see javax.servlet.Filter#destroy()
*/
public void destroy()
{
}
/**
* The log stream
*/
private static final Log log = LogFactory.getLog(DwrWebContextFilter.class);
/**
* The filter config, that we use to get at the servlet context
*/
private FilterConfig filterConfig;
}