EntityManagerBeanDefinitionRegistrarPostProcessor.java

/*
 * Copyright 2014 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.data.jpa.repository.support;

import static org.springframework.data.jpa.util.BeanDefinitionUtils.*;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.AutowireCandidateQualifier;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionReaderUtils;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.data.jpa.util.BeanDefinitionUtils.EntityManagerFactoryBeanDefinition;
import org.springframework.orm.jpa.SharedEntityManagerCreator;

/**
 * {@link BeanFactoryPostProcessor} to register a {@link SharedEntityManagerCreator} for every
 * {@link EntityManagerFactory} bean definition found in the application context to enable autowiring
 * {@link EntityManager} instances into constructor arguments. Adds the {@link EntityManagerFactory} bean name as
 * qualifier to the {@link EntityManager} {@link BeanDefinition} to enable explicit references in case of multiple
 * {@link EntityManagerFactory} instances.
 * 
 * @author Oliver Gierke
 */
public class EntityManagerBeanDefinitionRegistrarPostProcessor implements BeanFactoryPostProcessor {

	/* 
	 * (non-Javadoc)
	 * @see org.springframework.beans.factory.config.BeanFactoryPostProcessor#postProcessBeanFactory(org.springframework.beans.factory.config.ConfigurableListableBeanFactory)
	 */
	@Override
	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {

		for (EntityManagerFactoryBeanDefinition definition : getEntityManagerFactoryBeanDefinitions(beanFactory)) {

			if (!(definition.getBeanFactory() instanceof BeanDefinitionRegistry)) {
				continue;
			}

			BeanDefinitionBuilder builder = BeanDefinitionBuilder
					.rootBeanDefinition("org.springframework.orm.jpa.SharedEntityManagerCreator");
			builder.setFactoryMethod("createSharedEntityManager");
			builder.addConstructorArgReference(definition.getBeanName());

			AbstractBeanDefinition emBeanDefinition = builder.getRawBeanDefinition();

			emBeanDefinition.addQualifier(new AutowireCandidateQualifier(Qualifier.class, definition.getBeanName()));
			emBeanDefinition.setScope(definition.getBeanDefinition().getScope());
			emBeanDefinition.setSource(definition.getBeanDefinition().getSource());

			BeanDefinitionReaderUtils.registerWithGeneratedName(emBeanDefinition,
					(BeanDefinitionRegistry) definition.getBeanFactory());
		}
	}
}