/*
* Copyright (c) 2002-2006 by OpenSymphony
* All rights reserved.
*/
package com.opensymphony.xwork2.interceptor;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ModelDriven;
import com.opensymphony.xwork2.util.CompoundRoot;
import com.opensymphony.xwork2.util.ValueStack;
/**
* <!-- START SNIPPET: description -->
*
* Watches for {@link ModelDriven} actions and adds the action's model on to the value stack.
*
* <p/> <b>Note:</b> The ModelDrivenInterceptor must come before the both {@link StaticParametersInterceptor} and
* {@link ParametersInterceptor} if you want the parameters to be applied to the model.
*
* <p/> <b>Note:</b> The ModelDrivenInterceptor will only push the model into the stack when the
* model is not null, else it will be ignored.
*
* <!-- END SNIPPET: description -->
*
* <p/> <u>Interceptor parameters:</u>
*
* <!-- START SNIPPET: parameters -->
*
* <ul>
*
* <li>refreshModelBeforeResult - set to true if you want the model to be refreshed on the value stack after action
* execution and before result execution. The setting is useful if you want to change the model instance during the
* action execution phase, like when loading it from the data layer. This will result in getModel() being called at
* least twice.</li>
*
* </ul>
*
* <!-- END SNIPPET: parameters -->
*
* <p/> <u>Extending the interceptor:</u>
*
* <p/>
*
* <!-- START SNIPPET: extending -->
*
* There are no known extension points to this interceptor.
*
* <!-- END SNIPPET: extending -->
*
* <p/> <u>Example code:</u>
*
* <pre>
* <!-- START SNIPPET: example -->
* <action name="someAction" class="com.examples.SomeAction">
* <interceptor-ref name="modelDriven"/>
* <interceptor-ref name="basicStack"/>
* <result name="success">good_result.ftl</result>
* </action>
* <!-- END SNIPPET: example -->
* </pre>
*
* @author tm_jee
* @version $Date: 2009-07-28 02:25:13 +0200 (Di, 28 Jul 2009) $ $Id: ModelDrivenInterceptor.java 2027 2009-07-28 00:25:13Z musachy $
*/
public class ModelDrivenInterceptor extends AbstractInterceptor {
protected boolean refreshModelBeforeResult = false;
public void setRefreshModelBeforeResult(boolean val) {
this.refreshModelBeforeResult = val;
}
@Override
public String intercept(ActionInvocation invocation) throws Exception {
Object action = invocation.getAction();
if (action instanceof ModelDriven) {
ModelDriven modelDriven = (ModelDriven) action;
ValueStack stack = invocation.getStack();
Object model = modelDriven.getModel();
if (model != null) {
stack.push(model);
}
if (refreshModelBeforeResult) {
invocation.addPreResultListener(new RefreshModelBeforeResult(modelDriven, model));
}
}
return invocation.invoke();
}
/**
* Refreshes the model instance on the value stack, if it has changed
*/
protected static class RefreshModelBeforeResult implements PreResultListener {
private Object originalModel = null;
protected ModelDriven action;
public RefreshModelBeforeResult(ModelDriven action, Object model) {
this.originalModel = model;
this.action = action;
}
public void beforeResult(ActionInvocation invocation, String resultCode) {
ValueStack stack = invocation.getStack();
CompoundRoot root = stack.getRoot();
boolean needsRefresh = true;
Object newModel = action.getModel();
// Check to see if the new model instance is already on the stack
for (Object item : root) {
if (item.equals(newModel)) {
needsRefresh = false;
}
}
// Add the new model on the stack
if (needsRefresh) {
// Clear off the old model instance
if (originalModel != null) {
root.remove(originalModel);
}
if (newModel != null) {
stack.push(newModel);
}
}
}
}
}
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