Struts example source code file (ActionAutowiringInterceptor.java)

This example Struts source code file (ActionAutowiringInterceptor.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

abstractinterceptor, actionautowiringinterceptor, application_context, applicationcontext, applicationcontext, applicationcontextaware, exception, log, object, override, springobjectfactory, springobjectfactory, string, string

The Struts ActionAutowiringInterceptor.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.spring.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.AbstractInterceptor;
import com.opensymphony.xwork2.spring.SpringObjectFactory;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.web.context.WebApplicationContext;

/**
 * <!-- START SNIPPET: description -->
 * TODO: Give a description of the Interceptor.
 * <!-- END SNIPPET: description -->
 *
 * <!-- START SNIPPET: parameters -->
 * TODO: Describe the paramters for this Interceptor.
 * <!-- END SNIPPET: parameters -->
 *
 * <!-- START SNIPPET: extending -->
 * TODO: Discuss some possible extension of the Interceptor.
 * <!-- END SNIPPET: extending -->
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 * <!-- TODO: Describe how the Interceptor reference will effect execution -->
 * <action name="someAction" class="com.examples.SomeAction">
 *      TODO: fill in the interceptor reference.
 *     <interceptor-ref name=""/>
 *     <result name="success">good_result.ftl</result>
 * </action>
 * <!-- END SNIPPET: example -->
 * </pre>
 * 
 * Autowires action classes to Spring beans.  The strategy for autowiring the beans can be configured
 * by setting the parameter on the interceptor.  Actions that need access to the <code>ActionContext
 * can implements the <code>ApplicationContextAware interface.  The context will also be placed on
 * the action context under the APPLICATION_CONTEXT attribute.
 *
 * @author Simon Stewart
 * @author Eric Hauser
 */
public class ActionAutowiringInterceptor extends AbstractInterceptor implements ApplicationContextAware {
    private static final Logger LOG = LoggerFactory.getLogger(ActionAutowiringInterceptor.class);

    public static final String APPLICATION_CONTEXT = "com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor.applicationContext";

    private boolean initialized = false;
    private ApplicationContext context;
    private SpringObjectFactory factory;
    private Integer autowireStrategy;

    /**
     * @param autowireStrategy
     */
    public void setAutowireStrategy(Integer autowireStrategy) {
        this.autowireStrategy = autowireStrategy;
    }

    /**
     * Looks for the <code>ApplicationContext under the attribute that the Spring listener sets in
     * the servlet context.  The configuration is done the first time here instead of in init() since the
     * <code>ActionContext is not available during Interceptor initialization.
     * <p/>
     * Autowires the action to Spring beans and places the <code>ApplicationContext
     * on the <code>ActionContext
     * <p/>
     * TODO Should this check to see if the <code>SpringObjectFactory has already been configured
     * instead of instantiating a new one?  Or is there a good reason for the interceptor to have it's own
     * factory?
     *
     * @param invocation
     * @throws Exception
     */
    @Override public String intercept(ActionInvocation invocation) throws Exception {
        if (!initialized) {
            ApplicationContext applicationContext = (ApplicationContext) ActionContext.getContext().getApplication().get(
                    WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);

            if (applicationContext == null) {
                LOG.warn("ApplicationContext could not be found.  Action classes will not be autowired.");
            } else {
                setApplicationContext(applicationContext);
                factory = new SpringObjectFactory();
                factory.setApplicationContext(getApplicationContext());
                if (autowireStrategy != null) {
                    factory.setAutowireStrategy(autowireStrategy.intValue());
                }
            }
            initialized = true;
        }

        if (factory != null) {
            Object bean = invocation.getAction();
            factory.autoWireBean(bean);
    
            ActionContext.getContext().put(APPLICATION_CONTEXT, context);
        }
        return invocation.invoke();
    }

    /**
     * @param applicationContext
     * @throws BeansException
     */
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        context = applicationContext;
    }

    /**
     * @return context
     */
    protected ApplicationContext getApplicationContext() {
        return context;
    }

}