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Struts example source code file (AnnotationWorkflowInterceptor.java)

This example Struts source code file (AnnotationWorkflowInterceptor.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

annotationworkflowinterceptor, comparator, comparator, exception, interceptor, list, method, method, object, object, preresultlistener, reflection, string, string, util, xworkexception

The Struts AnnotationWorkflowInterceptor.java source code

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * Licensed 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 com.opensymphony.xwork2.interceptor.annotations;

import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.XWorkException;
import com.opensymphony.xwork2.interceptor.Interceptor;
import com.opensymphony.xwork2.interceptor.PreResultListener;
import com.opensymphony.xwork2.util.AnnotationUtils;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/**
 * <!-- START SNIPPET: javadoc -->
 * <p>Invokes any annotated methods on the action. Specifically, it supports the following
 * annotations:
 * <ul>
 * <li> @{@link Before} - will be invoked before the action method. If the returned value is not null, it is
 * returned as the action result code</li>
 * <li> @{@link BeforeResult} - will be invoked after the action method but before the result execution
 * <li> @{@link After} - will be invoked after the action method and result execution
 * </ul>
 * </p>
 * <p/>
 * <p>There can be multiple methods marked with the same annotations, but the order of their execution
 * is not guaranteed. However, the annotated methods on the superclass chain are guaranteed to be invoked before the
 * annotated method in the current class in the case of a {@link Before} annotations and after, if the annotations is
 * {@link After}.</p>
 * <!-- END SNIPPET: javadoc -->
 * <p/>
 * <pre>
 * <!-- START SNIPPET: javacode -->
 *  public class BaseAnnotatedAction {
 *  	protected String log = "";
 * <p/>
 *  	@Before
 *  	public String baseBefore() {
 *  		log = log + "baseBefore-";
 *  		return null;
 *  	}
 *  }
 * <p/>
 *  public class AnnotatedAction extends BaseAnnotatedAction {
 *  	@Before
 *  	public String before() {
 *  		log = log + "before";
 *  		return null;
 *  	}
 * <p/>
 *  	public String execute() {
 *  		log = log + "-execute";
 *  		return Action.SUCCESS;
 *  	}
 * <p/>
 *  	@BeforeResult
 *  	public void beforeResult() throws Exception {
 *  		log = log +"-beforeResult";
 *  	}
 * <p/>
 *  	@After
 *  	public void after() {
 *  		log = log + "-after";
 *  	}
 *  }
 * <!-- END SNIPPET: javacode -->
 *  </pre>
 * <p/>
 * <!-- START SNIPPET: example -->
 * <p>With the interceptor applied and the action executed on AnnotatedAction the log
 * instance variable will contain <code>baseBefore-before-execute-beforeResult-after.

* <!-- END SNIPPET: example --> * <p/> * <p/>Configure a stack in xwork.xml that replaces the PrepareInterceptor with the AnnotationWorkflowInterceptor: * <pre> * <!-- START SNIPPET: stack --> * <interceptor-stack name="annotatedStack"> * <interceptor-ref name="staticParams"/> * <interceptor-ref name="params"/> * <interceptor-ref name="conversionError"/> * <interceptor-ref name="annotationWorkflow"/> * </interceptor-stack> * <!-- END SNIPPET: stack --> * </pre> * * @author Zsolt Szasz, zsolt at lorecraft dot com * @author Rainer Hermanns * @author Dan Oxlade, dan d0t oxlade at gmail d0t c0m */ public class AnnotationWorkflowInterceptor implements Interceptor, PreResultListener { /** * Discovers annotated methods on the action and calls them according to the workflow * * @see com.opensymphony.xwork2.interceptor.Interceptor#intercept(com.opensymphony.xwork2.ActionInvocation) */ public String intercept(ActionInvocation invocation) throws Exception { final Object action = invocation.getAction(); invocation.addPreResultListener(this); List<Method> methods = new ArrayList(AnnotationUtils.getAnnotatedMethods(action.getClass(), Before.class)); if (methods.size() > 0) { // methods are only sorted by priority Collections.sort(methods, new Comparator<Method>() { public int compare(Method method1, Method method2) { return comparePriorities(method1.getAnnotation(Before.class).priority(), method2.getAnnotation(Before.class).priority()); } }); for (Method m : methods) { final String resultCode = (String) m .invoke(action, (Object[]) null); if (resultCode != null) { // shortcircuit execution return resultCode; } } } String invocationResult = invocation.invoke(); // invoke any @After methods methods = new ArrayList<Method>(AnnotationUtils.getAnnotatedMethods(action.getClass(), After.class)); if (methods.size() > 0) { // methods are only sorted by priority Collections.sort(methods, new Comparator<Method>() { public int compare(Method method1, Method method2) { return comparePriorities(method1.getAnnotation(After.class).priority(), method2.getAnnotation(After.class).priority()); } }); for (Method m : methods) { m.invoke(action, (Object[]) null); } } return invocationResult; } public void destroy() { } public void init() { } protected static int comparePriorities(int val1, int val2) { if (val2 < val1) { return -1; } else if (val2 > val1) { return 1; } else { return 0; } } /** * Invokes any @BeforeResult annotated methods * * @see com.opensymphony.xwork2.interceptor.PreResultListener#beforeResult(com.opensymphony.xwork2.ActionInvocation,String) */ public void beforeResult(ActionInvocation invocation, String resultCode) { Object action = invocation.getAction(); List<Method> methods = new ArrayList(AnnotationUtils.getAnnotatedMethods(action.getClass(), BeforeResult.class)); if (methods.size() > 0) { // methods are only sorted by priority Collections.sort(methods, new Comparator<Method>() { public int compare(Method method1, Method method2) { return comparePriorities(method1.getAnnotation(BeforeResult.class).priority(), method2.getAnnotation(BeforeResult.class).priority()); } }); for (Method m : methods) { try { m.invoke(action, (Object[]) null); } catch (Exception e) { throw new XWorkException(e); } } } } }

Other Struts examples (source code examples)

Here is a short list of links related to this Struts AnnotationWorkflowInterceptor.java source code file:

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