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Struts example source code file (ScopedModelDrivenInterceptor.java)

This example Struts source code file (ScopedModelDrivenInterceptor.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

actioncontext, class, class, empty_class_array, exception, get_model, map, object, object, objectfactory, reflection, scopedmodeldriven, scopedmodeldriven, string, string, util

The Struts ScopedModelDrivenInterceptor.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;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.XWorkException;
import com.opensymphony.xwork2.config.entities.ActionConfig;
import com.opensymphony.xwork2.inject.Inject;

import java.lang.reflect.Method;
import java.util.Map;

/**
 * <!-- START SNIPPET: description -->
 *
 * An interceptor that enables scoped model-driven actions.
 *
 * <p/>This interceptor only activates on actions that implement the {@link ScopedModelDriven} interface.  If
 * detected, it will retrieve the model class from the configured scope, then provide it to the Action.
 *  
 * <!-- END SNIPPET: description -->
 *
 * <p/> Interceptor parameters:
 *
 * <!-- START SNIPPET: parameters -->
 *
 * <ul>
 *
 * <li>className - The model class name.  Defaults to the class name of the object returned by the getModel() method.
 *            
 * <li>name - The key to use when storing or retrieving the instance in a scope.  Defaults to the model
 *            class name.</li>
 *
 * <li>scope - The scope to store and retrieve the model.  Defaults to 'request' but can also be 'session'.
 * </ul>
 *
 * <!-- END SNIPPET: parameters -->
 *
 * <p/> Extending the interceptor:
 *
 * <p/>
 *
 * <!-- START SNIPPET: extending -->
 *
 * There are no known extension points for this interceptor.
 *
 * <!-- END SNIPPET: extending -->
 *
 * <p/> Example code:
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 * 
 * <-- Basic usage -->
 * <interceptor name="scopedModelDriven" class="com.opensymphony.interceptor.ScopedModelDrivenInterceptor" />
 * 
 * <-- Using all available parameters -->
 * <interceptor name="gangsterForm" class="com.opensymphony.interceptor.ScopedModelDrivenInterceptor">
 *      <param name="scope">session</param>
 *      <param name="name">gangsterForm</param>
 *      <param name="className">com.opensymphony.example.GangsterForm</param>
 *  </interceptor>
 * 
 * <!-- END SNIPPET: example -->
 * </pre>
 */
public class ScopedModelDrivenInterceptor extends AbstractInterceptor {

    private static final Class[] EMPTY_CLASS_ARRAY = new Class[0];
    
    private static final String GET_MODEL = "getModel";
    private String scope;
    private String name;
    private String className;
    private ObjectFactory objectFactory;
    
    @Inject
    public void setObjectFactory(ObjectFactory factory) {
        this.objectFactory = factory;
    }
    
    protected Object resolveModel(ObjectFactory factory, ActionContext actionContext, String modelClassName, String modelScope, String modelName) throws Exception {
        Object model = null;
        Map<String, Object> scopeMap = actionContext.getContextMap();
        if ("session".equals(modelScope)) {
            scopeMap = actionContext.getSession();
        }
        
        model = scopeMap.get(modelName);
        if (model == null) {
            model = factory.buildBean(modelClassName, null);
            scopeMap.put(modelName, model);
        }
        return model;
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        Object action = invocation.getAction();

        if (action instanceof ScopedModelDriven) {
            ScopedModelDriven modelDriven = (ScopedModelDriven) action;
            if (modelDriven.getModel() == null) {
                ActionContext ctx = ActionContext.getContext();
                ActionConfig config = invocation.getProxy().getConfig();
                
                String cName = className;
                if (cName == null) {
                    try {
                        Method method = action.getClass().getMethod(GET_MODEL, EMPTY_CLASS_ARRAY);
                        Class cls = method.getReturnType();
                        cName = cls.getName();
                    } catch (NoSuchMethodException e) {
                        throw new XWorkException("The " + GET_MODEL + "() is not defined in action " + action.getClass() + "", config);
                    }
                }
                String modelName = name;
                if (modelName == null) {
                    modelName = cName;
                }
                Object model = resolveModel(objectFactory, ctx, cName, scope, modelName);
                modelDriven.setModel(model);
                modelDriven.setScopeKey(modelName);
            }
        }
        return invocation.invoke();
    }

    /**
     * @param className the className to set
     */
    public void setClassName(String className) {
        this.className = className;
    }

    /**
     * @param name the name to set
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * @param scope the scope to set
     */
    public void setScope(String scope) {
        this.scope = scope;
    }    
}

Other Struts examples (source code examples)

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

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