Java tutorial
/* * $Id: ActionContextCleanUp.java 484717 2006-12-08 19:57:59Z mrdon $ * * 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.struts2.dispatcher; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; 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 com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ObjectFactory; import com.opensymphony.xwork2.util.profiling.UtilTimerStack; /** * <!-- SNIPPET START: description --> * Special filter designed to work with the {@link FilterDispatcher} and allow * for easier integration with SiteMesh. Normally, ordering your filters to have * SiteMesh go first, and then {@link FilterDispatcher} go second is perfectly fine. * However, sometimes you may wish to access Struts features, including the * value stack, from within your SiteMesh decorators. Because {@link FilterDispatcher} * cleans up the {@link ActionContext}, your decorator won't have access to the * data you want. * <p/> * <p/> * By adding this filter, the {@link FilterDispatcher} will know to not clean up and * instead defer cleanup to this filter. The ordering of the filters should then be: * <p/> * <ul> * <li>this filter</li> * <li>SiteMesh filter</li> * <li>{@link FilterDispatcher}</li> * </ul> * <!-- SNIPPET END: description --> * * * @see FilterDispatcher * @see AbstractFilter * @see Dispatcher * * @version $Date: 2006-12-08 14:57:59 -0500 (Fri, 08 Dec 2006) $ $Id: ActionContextCleanUp.java 484717 2006-12-08 19:57:59Z mrdon $ */ public class ActionContextCleanUp implements Filter { private static final Log LOG = LogFactory.getLog(ActionContextCleanUp.class); private static final String COUNTER = "__cleanup_recursion_counter"; /** * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain) */ public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) res; String timerKey = "ActionContextCleanUp_doFilter: "; try { UtilTimerStack.push(timerKey); try { Integer count = (Integer) request.getAttribute(COUNTER); if (count == null) { count = new Integer(1); } else { count = new Integer(count.intValue() + 1); } request.setAttribute(COUNTER, count); //LOG.debug("filtering counter="+count); chain.doFilter(request, response); } finally { int counterVal = ((Integer) request.getAttribute(COUNTER)).intValue(); counterVal -= 1; request.setAttribute(COUNTER, new Integer(counterVal)); cleanUp(request); } } finally { UtilTimerStack.pop(timerKey); } } /** * Clean up the request of threadlocals if this is the last execution * * @param req The servlet request */ protected static void cleanUp(ServletRequest req) { // should we clean up yet? Integer count = (Integer) req.getAttribute(COUNTER); if (count != null && count > 0) { if (LOG.isDebugEnabled()) { LOG.debug("skipping cleanup counter=" + count); } return; } // always dontClean up the thread request, even if an action hasn't been executed ActionContext.setContext(null); Dispatcher.setInstance(null); } public void destroy() { } public void init(FilterConfig arg0) throws ServletException { } }