Struts example source code file (ServletDispatcherResult.java)

This example Struts source code file (ServletDispatcherResult.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

actioninvocation, boolean, boolean, forwarding, forwarding, http, httpservletrequest, httpservletresponse, logger, map, map, request, requestdispatcher, response, servlet, servletdispatcherresult, servletdispatcherresult, string, util

The Struts ServletDispatcherResult.java source code

/*
 * $Id: ServletDispatcherResult.java 1076544 2011-03-03 07:19:37Z lukaszlenart $
 *
 * 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 com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.apache.commons.lang.ObjectUtils;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.StrutsStatics;
import org.apache.struts2.views.util.UrlHelper;

import javax.servlet.RequestDispatcher;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.PageContext;
import java.util.Map;


/**
 * <!-- START SNIPPET: description -->
 *
 * Includes or forwards to a view (usually a jsp). Behind the scenes Struts
 * will use a RequestDispatcher, where the target servlet/JSP receives the same
 * request/response objects as the original servlet/JSP. Therefore, you can pass
 * data between them using request.setAttribute() - the Struts action is
 * available.
 * <p/>
 * There are three possible ways the result can be executed:
 *
 * <ul>
 *
 * <li>If we are in the scope of a JSP (a PageContext is available), PageContext's
 * {@link PageContext#include(String) include} method is called.</li>
 *
 * <li>If there is no PageContext and we're not in any sort of include (there is no
 * "javax.servlet.include.servlet_path" in the request attributes), then a call to
 * {@link RequestDispatcher#forward(javax.servlet.ServletRequest, javax.servlet.ServletResponse) forward}
 * is made.</li>
 *
 * <li>Otherwise, {@link RequestDispatcher#include(javax.servlet.ServletRequest, javax.servlet.ServletResponse) include}
 * is called.</li>
 *
 * </ul>
 * <!-- END SNIPPET: description -->
 *
 * <b>This result type takes the following parameters:
 *
 * <!-- START SNIPPET: params -->
 *
 * <ul>
 *
 * <li>location (default) - the location to go to after execution (ex. jsp).
 *
 * <li>parse - true by default. If set to false, the location param will not be parsed for Ognl expressions.
 *
 * </ul>
 *
 * <!-- END SNIPPET: params -->
 *
 * <b>Example:
 *
 * <pre>
 * <result name="success" type="dispatcher">
 *   <param name="location">foo.jsp</param>
 * </result>
 * <!-- END SNIPPET: example -->

* * This result follows the same rules from {@link StrutsResultSupport}. * * @see javax.servlet.RequestDispatcher */ public class ServletDispatcherResult extends StrutsResultSupport { private static final long serialVersionUID = -1970659272360685627L; private static final Logger LOG = LoggerFactory.getLogger(ServletDispatcherResult.class); public ServletDispatcherResult() { super(); } public ServletDispatcherResult(String location) { super(location); } /** * Dispatches to the given location. Does its forward via a RequestDispatcher. If the * dispatch fails a 404 error will be sent back in the http response. * * @param finalLocation the location to dispatch to. * @param invocation the execution state of the action * @throws Exception if an error occurs. If the dispatch fails the error will go back via the * HTTP request. */ public void doExecute(String finalLocation, ActionInvocation invocation) throws Exception { if (LOG.isDebugEnabled()) { LOG.debug("Forwarding to location " + finalLocation); } PageContext pageContext = ServletActionContext.getPageContext(); if (pageContext != null) { pageContext.include(finalLocation); } else { HttpServletRequest request = ServletActionContext.getRequest(); HttpServletResponse response = ServletActionContext.getResponse(); RequestDispatcher dispatcher = request.getRequestDispatcher(finalLocation); //add parameters passed on the location to #parameters // see WW-2120 if (invocation != null && finalLocation != null && finalLocation.length() > 0 && finalLocation.indexOf("?") > 0) { String queryString = finalLocation.substring(finalLocation.indexOf("?") + 1); Map parameters = (Map) invocation.getInvocationContext().getContextMap().get("parameters"); Map queryParams = UrlHelper.parseQueryString(queryString, true); if (queryParams != null && !queryParams.isEmpty()) parameters.putAll(queryParams); } // if the view doesn't exist, let's do a 404 if (dispatcher == null) { response.sendError(404, "result '" + finalLocation + "' not found"); return; } //if we are inside an action tag, we always need to do an include Boolean insideActionTag = (Boolean) ObjectUtils.defaultIfNull(request.getAttribute(StrutsStatics.STRUTS_ACTION_TAG_INVOCATION), Boolean.FALSE); // If we're included, then include the view // Otherwise do forward // This allow the page to, for example, set content type if (!insideActionTag && !response.isCommitted() && (request.getAttribute("javax.servlet.include.servlet_path") == null)) { request.setAttribute("struts.view_uri", finalLocation); request.setAttribute("struts.request_uri", request.getRequestURI()); dispatcher.forward(request, response); } else { dispatcher.include(request, response); } } } }