/*
 * Copyright 2002-2008 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.scope;

import org.springframework.aop.framework.autoproxy.AutoProxyUtils;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanDefinitionHolder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.RootBeanDefinition;

/**
 * Utility class for creating a scoped proxy.
 * Used by ScopedProxyBeanDefinitionDecorator and ClassPathBeanDefinitionScanner.
 *
 * @author Mark Fisher
 * @author Juergen Hoeller
 * @author Rob Harrop
 * @since 2.5
 */
public abstract class ScopedProxyUtils {

	private static final String TARGET_NAME_PREFIX = "scopedTarget.";


	/**
	 * Generates a scoped proxy for the supplied target bean, registering the target
	 * bean with an internal name and setting 'targetBeanName' on the scoped proxy.
	 * @param definition the original bean definition
	 * @param registry the bean definition registry
	 * @param proxyTargetClass whether to create a target class proxy
	 * @return the scoped proxy definition
	 */
	public static BeanDefinitionHolder createScopedProxy(BeanDefinitionHolder definition,
			BeanDefinitionRegistry registry, boolean proxyTargetClass) {
		
		String originalBeanName = definition.getBeanName();
		BeanDefinition targetDefinition = definition.getBeanDefinition();

		// Create a scoped proxy definition for the original bean name,
		// "hiding" the target bean in an internal target definition.
		RootBeanDefinition scopedProxyDefinition = new RootBeanDefinition(ScopedProxyFactoryBean.class);
		scopedProxyDefinition.setOriginatingBeanDefinition(definition.getBeanDefinition());
		scopedProxyDefinition.setSource(definition.getSource());
		scopedProxyDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
		
		String targetBeanName = getTargetBeanName(originalBeanName);
		scopedProxyDefinition.getPropertyValues().addPropertyValue("targetBeanName", targetBeanName);

		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);
		}

		scopedProxyDefinition.setAutowireCandidate(targetDefinition.isAutowireCandidate());
		// The target bean should be ignored in favor of the scoped proxy.
		targetDefinition.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());
	}
	
	/**
	 * Generates the bean name that is used within the scoped proxy to reference the target bean.
	 * @param originalBeanName the original name of bean
	 * @return the generated bean to be used to reference the target bean
	 */
	public static String getTargetBeanName(String originalBeanName) {
		return TARGET_NAME_PREFIX + originalBeanName;
	}

}