/*
* $Id: StrutsResultSupport.java 557291 2007-07-18 15:17:41Z jholmes $
*
* 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.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts2.StrutsStatics;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.util.TextParseUtil;
/**
* <!-- 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>
* <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</li>
* </ul>
*
* <b>NOTE:</b>
* 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</b>">foo.jsp</param>
* </result></pre>
* <p/>
* or
* <p/>
* <pre>
* <result name="success" type="redirect" >
* <param name="<b>location</b>">foo.jsp?url=${myUrl}</param>
* <param name="<b>parse</b>">true</param>
* <param name="<b>encode</b>">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</b></result></pre>
* <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 Log _log = LogFactory.getLog(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</tt>
* parameter is set to <tt>true</tt>.
*
* @param location the location to go to after action execution.
* @see #setParse(boolean)
*/
public void setLocation(String location) {
this.location = location;
}
/**
* Returns the last parsed and encoded location value
*/
public String getLastFinalLocation() {
return lastFinalLocation;
}
/**
* Set parse to <tt>true</tt> to indicate that the location should be parsed as an OGNL expression. This
* is set to <tt>true</tt> by default.
*
* @param parse <tt>true</tt> if the location parameter is an OGNL expression, <tt>false</tt> otherwise.
*/
public void setParse(boolean parse) {
this.parse = parse;
}
/**
* Set encode to <tt>true</tt> to indicate that the location should be url encoded. This is set to
* <tt>true</tt> by default
*
* @param encode <tt>true</tt> if the location parameter should be url encode, <tt>false</tt> otherwise.
*/
public void setEncode(boolean encode) {
this.encode = encode;
}
/**
* Implementation of the <tt>execute</tt> method from the <tt>Result</tt> 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;
}
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