Struts example source code file (StrutsResultSupport.java)

This example Struts source code file (StrutsResultSupport.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, actioninvocation, default_param, exception, exception, io, logger, net, network, object, result, string, string, strutsresultsupport, strutsresultsupport, strutsstatics, utf-8

The Struts StrutsResultSupport.java source code

/*
 * $Id: StrutsResultSupport.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * 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.UnsupportedEncodingException;
import java.net.URLEncoder;

import org.apache.struts2.StrutsStatics;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.util.TextParseUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;


/**
 * <!-- START SNIPPET: javadoc -->
 *
 * A base class for all Struts action execution results.
 * The "location" param is the default parameter, meaning the most common usage of this result would be:
 * <p/>
 * This class provides two common parameters for any subclass:
 * <ul>
 * <li>location - the location to go to after execution (could be a jsp page or another action).
 * It can be parsed as per the rules definied in the
 * {@link TextParseUtil#translateVariables(java.lang.String, com.opensymphony.xwork2.util.ValueStack) translateVariables}
 * method</li>
 * <li>parse - true by default. If set to false, the location param will not be parsed for expressions
 * <li>encode - false by default. If set to false, the location param will not be url encoded. This only have effect when parse is true
 * </ul>
 *
 * <b>NOTE:
 * The encode param will only have effect when parse is true
 *
 * <!-- END SNIPPET: javadoc -->
 *
 * <p/>
 *
 * <!-- START SNIPPET: example -->
 *
 * <p/>
 * In the struts.xml configuration file, these would be included as:
 * <p/>
 * <pre>
 *  <result name="success" type="redirect">
 *      <param name="<b>location">foo.jsp</param>
 *  </result></pre>
 * <p/>
 * or
 * <p/>
 * <pre>
 *  <result name="success" type="redirect" >
 *      <param name="<b>location">foo.jsp?url=${myUrl}</param>
 *      <param name="<b>parse">true</param>
 *      <param name="<b>encode">true</param>
 *  </result></pre>
 * <p/>
 * In the above case, myUrl will be parsed against Ognl Value Stack and then
 * URL encoded.
 * <p/>
 * or when using the default parameter feature
 * <p/>
 * <pre>
 *  <result name="success" type="redirect"><b>foo.jsp</result>

* <p/> * You should subclass this class if you're interested in adding more parameters or functionality * to your Result. If you do subclass this class you will need to * override {@link #doExecute(String, ActionInvocation)}.<p> * <p/> * Any custom result can be defined in struts.xml as: * <p/> * <pre> * <result-types> * ... * <result-type name="myresult" class="com.foo.MyResult" /> * </result-types></pre> * <p/> * Please see the {@link com.opensymphony.xwork2.Result} class for more info on Results in general. * * <!-- END SNIPPET: example --> * * @see com.opensymphony.xwork2.Result */ public abstract class StrutsResultSupport implements Result, StrutsStatics { private static final Logger LOG = LoggerFactory.getLogger(StrutsResultSupport.class); /** The default parameter */ public static final String DEFAULT_PARAM = "location"; private boolean parse; private boolean encode; private String location; private String lastFinalLocation; public StrutsResultSupport() { this(null, true, false); } public StrutsResultSupport(String location) { this(location, true, false); } public StrutsResultSupport(String location, boolean parse, boolean encode) { this.location = location; this.parse = parse; this.encode = encode; } /** * The location to go to after action execution. This could be a JSP page or another action. * The location can contain OGNL expressions which will be evaulated if the <tt>parse * parameter is set to <tt>true. * * @param location the location to go to after action execution. * @see #setParse(boolean) */ public void setLocation(String location) { this.location = location; } /** * Gets the location it was created with, mainly for testing */ public String getLocation() { return location; } /** * Returns the last parsed and encoded location value */ public String getLastFinalLocation() { return lastFinalLocation; } /** * Set parse to <tt>true to indicate that the location should be parsed as an OGNL expression. This * is set to <tt>true by default. * * @param parse <tt>true if the location parameter is an OGNL expression, false otherwise. */ public void setParse(boolean parse) { this.parse = parse; } /** * Set encode to <tt>true to indicate that the location should be url encoded. This is set to * <tt>true by default * * @param encode <tt>true if the location parameter should be url encode, false otherwise. */ public void setEncode(boolean encode) { this.encode = encode; } /** * Implementation of the <tt>execute method from the Result interface. This will call * the abstract method {@link #doExecute(String, ActionInvocation)} after optionally evaluating the * location as an OGNL evaluation. * * @param invocation the execution state of the action. * @throws Exception if an error occurs while executing the result. */ public void execute(ActionInvocation invocation) throws Exception { lastFinalLocation = conditionalParse(location, invocation); doExecute(lastFinalLocation, invocation); } /** * Parses the parameter for OGNL expressions against the valuestack * * @param param The parameter value * @param invocation The action invocation instance * @return The resulting string */ protected String conditionalParse(String param, ActionInvocation invocation) { if (parse && param != null && invocation != null) { return TextParseUtil.translateVariables(param, invocation.getStack(), new TextParseUtil.ParsedValueEvaluator() { public Object evaluate(Object parsedValue) { if (encode) { if (parsedValue != null) { try { // use UTF-8 as this is the recommended encoding by W3C to // avoid incompatibilities. return URLEncoder.encode(parsedValue.toString(), "UTF-8"); } catch(UnsupportedEncodingException e) { LOG.warn("error while trying to encode ["+parsedValue+"]", e); } } } return parsedValue; } }); } else { return param; } } /** * Executes the result given a final location (jsp page, action, etc) and the action invocation * (the state in which the action was executed). Subclasses must implement this class to handle * custom logic for result handling. * * @param finalLocation the location (jsp page, action, etc) to go to. * @param invocation the execution state of the action. * @throws Exception if an error occurs while executing the result. */ protected abstract void doExecute(String finalLocation, ActionInvocation invocation) throws Exception; }