org.springframework.aop.framework.autoproxy.target.AbstractPrototypeBasedTargetSourceCreator.java Source code

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Here is the source code for org.springframework.aop.framework.autoproxy.target.AbstractPrototypeBasedTargetSourceCreator.java

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/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * 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 org.springframework.aop.framework.autoproxy.target;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.autoproxy.TargetSourceCreator;
import org.springframework.aop.target.AbstractPrototypeBasedTargetSource;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.DefaultListableBeanFactory;
import org.springframework.beans.factory.support.RootBeanDefinition;

/**
 * Convenient superclass for TargetSourceCreators that require creating
 * multiple instances of a prototype bean.
 * @author Rod Johnson
 * @see org.springframework.aop.target.AbstractPrototypeBasedTargetSource
 */
public abstract class AbstractPrototypeBasedTargetSourceCreator implements TargetSourceCreator {

    protected final Log logger = LogFactory.getLog(getClass());

    public final TargetSource getTargetSource(Object bean, String beanName, BeanFactory factory) {
        AbstractPrototypeBasedTargetSource prototypeTargetSource = createPrototypeTargetSource(bean, beanName,
                factory);
        if (prototypeTargetSource == null) {
            return null;
        } else {
            if (!(factory instanceof BeanDefinitionRegistry)) {
                logger.warn(
                        "Cannot do autopooling with a BeanFactory that doesn't implement BeanDefinitionRegistry");
                return null;
            }
            BeanDefinitionRegistry definitionRegistry = (BeanDefinitionRegistry) factory;
            RootBeanDefinition definition = (RootBeanDefinition) definitionRegistry.getBeanDefinition(beanName);

            logger.info("Configuring AbstractPrototypeBasedTargetSource...");

            // Infinite cycle will result if we don't use a different factory,
            // because a getBean() call with this beanName will go through the autoproxy
            // infrastructure again.
            // We to override just this bean definition, as it may reference other beans
            // and we're happy to take the parent's definition for those.
            DefaultListableBeanFactory beanFactory2 = new DefaultListableBeanFactory(factory);

            // Override the prototype bean
            beanFactory2.registerBeanDefinition(beanName, definition);

            // Complete configuring the PrototypeTargetSource
            prototypeTargetSource.setTargetBeanName(beanName);
            prototypeTargetSource.setBeanFactory(beanFactory2);

            return prototypeTargetSource;
        }
    }

    /**
     * Subclasses must implement this method to return a new AbstractPrototypeBasedTargetSource
     * if they wish to create a custom TargetSource for this bean, or null if they are
     * not interested it in, in which case no special target source will be created.
     * Subclasses should not call setTargetBeanName() or setBeanFactory() on the
     * AbstractPrototypeBasedTargetSource: This class's implementation of getTargetSource()
     * will do that.
     * @return the AbstractPrototypeBasedTargetSource, or null if we don't match this
     */
    protected abstract AbstractPrototypeBasedTargetSource createPrototypeTargetSource(Object bean, String beanName,
            BeanFactory factory);

}