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Struts example source code file (ObjectFactory.java)

This example Struts source code file (ObjectFactory.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

class, exception, exception, inject, interceptor, io, map, map, object, object, objectfactory, result, string, string, util, validator

The Struts ObjectFactory.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;

import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.config.entities.ActionConfig;
import com.opensymphony.xwork2.config.entities.InterceptorConfig;
import com.opensymphony.xwork2.config.entities.ResultConfig;
import com.opensymphony.xwork2.inject.Container;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.interceptor.Interceptor;
import com.opensymphony.xwork2.util.ClassLoaderUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import com.opensymphony.xwork2.util.reflection.ReflectionException;
import com.opensymphony.xwork2.util.reflection.ReflectionExceptionHandler;
import com.opensymphony.xwork2.util.reflection.ReflectionProvider;
import com.opensymphony.xwork2.validator.Validator;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;


/**
 * ObjectFactory is responsible for building the core framework objects. Users may register their 
 * own implementation of the ObjectFactory to control instantiation of these Objects.
 * <p/>
 * This default implementation uses the {@link #buildBean(Class,java.util.Map) buildBean} 
 * method to create all classes (interceptors, actions, results, etc).
 * <p/>
 *
 * @author Jason Carreira
 */
public class ObjectFactory implements Serializable {
    private static final Logger LOG = LoggerFactory.getLogger(ObjectFactory.class);

    private transient ClassLoader ccl;
    private Container container;
    protected ReflectionProvider reflectionProvider;

    @Inject(value="objectFactory.classloader", required=false)
    public void setClassLoader(ClassLoader cl) {
        this.ccl = cl;
    }
    
    @Inject
    public void setReflectionProvider(ReflectionProvider prov) {
        this.reflectionProvider = prov;
    }

    public ObjectFactory() {
    }
    
    public ObjectFactory(ReflectionProvider prov) {
        this.reflectionProvider = prov;
    }
    
    @Inject
    public void setContainer(Container container) {
        this.container = container;
    }

    /**
     * @deprecated Since 2.1
     */
    @Deprecated public static ObjectFactory getObjectFactory() {
        return ActionContext.getContext().getContainer().getInstance(ObjectFactory.class);
    }

    /**
     * Allows for ObjectFactory implementations that support
     * Actions without no-arg constructors.
     *
     * @return true if no-arg constructor is required, false otherwise
     */
    public boolean isNoArgConstructorRequired() {
        return true;
    }

    /**
     * Utility method to obtain the class matched to className. Caches look ups so that subsequent
     * lookups will be faster.
     *
     * @param className The fully qualified name of the class to return
     * @return The class itself
     * @throws ClassNotFoundException
     */
    public Class getClassInstance(String className) throws ClassNotFoundException {
        if (ccl != null) {
            return ccl.loadClass(className);
        }

        return ClassLoaderUtil.loadClass(className, this.getClass());
    }

    /**
     * Build an instance of the action class to handle a particular request (eg. web request)
     * @param actionName the name the action configuration is set up with in the configuration
     * @param namespace the namespace the action is configured in
     * @param config the action configuration found in the config for the actionName / namespace
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     * @return instance of the action class to handle a web request
     * @throws Exception
     */
    public Object buildAction(String actionName, String namespace, ActionConfig config, Map<String, Object> extraContext) throws Exception {
        return buildBean(config.getClassName(), extraContext);
    }

    /**
     * Build a generic Java object of the given type.
     *
     * @param clazz the type of Object to build
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     */
    public Object buildBean(Class clazz, Map<String, Object> extraContext) throws Exception {
        return clazz.newInstance();
    }

    /**
     * @param obj
     */
    protected Object injectInternalBeans(Object obj) {
        if (obj != null && container != null) {
            container.inject(obj);
        }
        return obj;
    }

    /**
     * Build a generic Java object of the given type.
     *
     * @param className the type of Object to build
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     */
    public Object buildBean(String className, Map<String, Object> extraContext) throws Exception {
        return buildBean(className, extraContext, true);
    }
    
    /**
     * Build a generic Java object of the given type.
     *
     * @param className the type of Object to build
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     */
    public Object buildBean(String className, Map<String, Object> extraContext, boolean injectInternal) throws Exception {
        Class clazz = getClassInstance(className);
        Object obj = buildBean(clazz, extraContext);
        if (injectInternal) {
            injectInternalBeans(obj);
        }
        return obj;
    }

    /**
     * Builds an Interceptor from the InterceptorConfig and the Map of
     * parameters from the interceptor reference. Implementations of this method
     * should ensure that the Interceptor is parameterized with both the
     * parameters from the Interceptor config and the interceptor ref Map (the
     * interceptor ref params take precedence), and that the Interceptor.init()
     * method is called on the Interceptor instance before it is returned.
     *
     * @param interceptorConfig    the InterceptorConfig from the configuration
     * @param interceptorRefParams a Map of params provided in the Interceptor reference in the
     *                             Action mapping or InterceptorStack definition
     */
    public Interceptor buildInterceptor(InterceptorConfig interceptorConfig, Map<String, String> interceptorRefParams) throws ConfigurationException {
        String interceptorClassName = interceptorConfig.getClassName();
        Map<String, String> thisInterceptorClassParams = interceptorConfig.getParams();
        Map<String, String> params = (thisInterceptorClassParams == null) ? new HashMap() : new HashMap(thisInterceptorClassParams);
        params.putAll(interceptorRefParams);

        String message;
        Throwable cause;

        try {
            // interceptor instances are long-lived and used across user sessions, so don't try to pass in any extra context
            Interceptor interceptor = (Interceptor) buildBean(interceptorClassName, null);
            reflectionProvider.setProperties(params, interceptor);
            interceptor.init();

            return interceptor;
        } catch (InstantiationException e) {
            cause = e;
            message = "Unable to instantiate an instance of Interceptor class [" + interceptorClassName + "].";
        } catch (IllegalAccessException e) {
            cause = e;
            message = "IllegalAccessException while attempting to instantiate an instance of Interceptor class [" + interceptorClassName + "].";
        } catch (ClassCastException e) {
            cause = e;
            message = "Class [" + interceptorClassName + "] does not implement com.opensymphony.xwork2.interceptor.Interceptor";
        } catch (Exception e) {
            cause = e;
            message = "Caught Exception while registering Interceptor class " + interceptorClassName;
        } catch (NoClassDefFoundError e) {
            cause = e;
            message = "Could not load class " + interceptorClassName + ". Perhaps it exists but certain dependencies are not available?";
        }

        throw new ConfigurationException(message, cause, interceptorConfig);
    }

    /**
     * Build a Result using the type in the ResultConfig and set the parameters in the ResultConfig.
     *
     * @param resultConfig the ResultConfig found for the action with the result code returned
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     */
    public Result buildResult(ResultConfig resultConfig, Map<String, Object> extraContext) throws Exception {
        String resultClassName = resultConfig.getClassName();
        Result result = null;

        if (resultClassName != null) {
            result = (Result) buildBean(resultClassName, extraContext);
            Map<String, String> params = resultConfig.getParams();
            if (params != null) {
                for (Map.Entry<String, String> paramEntry : params.entrySet()) {
                    try {
                        reflectionProvider.setProperty(paramEntry.getKey(), paramEntry.getValue(), result, extraContext, true);
                    } catch (ReflectionException ex) {
                        if (result instanceof ReflectionExceptionHandler) {
                            ((ReflectionExceptionHandler) result).handle(ex);
                        }
                    }
                }
            }
        }

        return result;
    }

    /**
     * Build a Validator of the given type and set the parameters on it
     *
     * @param className the type of Validator to build
     * @param params    property name -> value Map to set onto the Validator instance
     * @param extraContext a Map of extra context which uses the same keys as the {@link com.opensymphony.xwork2.ActionContext}
     */
    public Validator buildValidator(String className, Map<String, String> params, Map extraContext) throws Exception {
        Validator validator = (Validator) buildBean(className, null);
        reflectionProvider.setProperties(params, validator);

        return validator;
    }

    static class ContinuationsClassLoader extends ClassLoader {
        
    }
}

Other Struts examples (source code examples)

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