scopedproxybeandefinitiondecorator.java

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/*
 * Copyright 2002-2007 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.config;

import org.w3c.dom.Element;
import org.w3c.dom.Node;

import org.springframework.aop.framework.autoproxy.AutoProxyUtils;
import org.springframework.aop.scope.ScopedProxyFactoryBean;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;
import org.springframework.beans.factory.xml.BeanDefinitionDecorator;
import org.springframework.beans.factory.xml.ParserContext;

/**
 * {@link BeanDefinitionDecorator} responsible for parsing the
 * <code>&lt;aop:scoped-proxy/&gt;</code> tag.
 *
 * @author Rob Harrop
 * @author Juergen Hoeller
 * @since 2.0
 */
class ScopedProxyBeanDefinitionDecorator implements BeanDefinitionDecorator {

	private static final String PROXY_TARGET_CLASS = "proxy-target-class";

	private static final String TARGET_NAME_PREFIX = "scopedTarget.";


	public BeanDefinitionHolder decorate(Node node, BeanDefinitionHolder definition, ParserContext parserContext) {
		String originalBeanName = definition.getBeanName();
		BeanDefinition targetDefinition = definition.getBeanDefinition();
		BeanDefinitionRegistry registry = parserContext.getRegistry();

		// Create a scoped proxy definition for the original bean name,
		// "hiding" the target bean in an internal target definition.
		String targetBeanName = TARGET_NAME_PREFIX + originalBeanName;
		RootBeanDefinition scopedProxyDefinition = new RootBeanDefinition(ScopedProxyFactoryBean.class);
		scopedProxyDefinition.getPropertyValues().addPropertyValue("targetBeanName", targetBeanName);

		boolean proxyTargetClass = true;
		if (node instanceof Element) {
			Element ele = (Element) node;
			if (ele.hasAttribute(PROXY_TARGET_CLASS)) {
				proxyTargetClass = Boolean.valueOf(ele.getAttribute(PROXY_TARGET_CLASS)).booleanValue();
			}
		}
		if (proxyTargetClass) {
			targetDefinition.setAttribute(AutoProxyUtils.PRESERVE_TARGET_CLASS_ATTRIBUTE, Boolean.TRUE);
			// ScopedFactoryBean's "proxyTargetClass" default is TRUE, so we don't need to set it explicitly here.
		}
		else {
			scopedProxyDefinition.getPropertyValues().addPropertyValue("proxyTargetClass", Boolean.FALSE);
		}

		if (targetDefinition instanceof AbstractBeanDefinition) {
			AbstractBeanDefinition abd = (AbstractBeanDefinition) targetDefinition;
			scopedProxyDefinition.setAutowireCandidate(abd.isAutowireCandidate());
			// The target bean should be ignored in favor of the scoped proxy.
			abd.setAutowireCandidate(false);
		}

		// Register the target bean as separate bean in the factory.
		registry.registerBeanDefinition(targetBeanName, targetDefinition);

		// Return the scoped proxy definition as primary bean definition
		// (potentially an inner bean).
		return new BeanDefinitionHolder(scopedProxyDefinition, originalBeanName, definition.getAliases());
	}

}