DataSourceInitializerPostProcessor.java

/*
 * Copyright 2012-2014 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.boot.autoconfigure.jdbc;

import javax.sql.DataSource;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.GenericBeanDefinition;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.Ordered;
import org.springframework.core.type.AnnotationMetadata;

/**
 * {@link BeanPostProcessor} used to fire {@link DataSourceInitializedEvent}s. Should only
 * be registered via the inner {@link Registrar} class.
 *
 * @author Dave Syer
 * @since 1.1.2
 */
class DataSourceInitializerPostProcessor implements BeanPostProcessor, Ordered {

	private int order = Ordered.HIGHEST_PRECEDENCE;

	@Override
	public int getOrder() {
		return this.order;
	}

	@Autowired
	private BeanFactory beanFactory;

	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName)
			throws BeansException {
		if (bean instanceof DataSource) {
			// force initialization of this bean as soon as we see a DataSource
			this.beanFactory.getBean(DataSourceInitializer.class);
		}
		return bean;
	}

	/**
	 * {@link ImportBeanDefinitionRegistrar} to register the
	 * {@link DataSourceInitializerPostProcessor} without causing early bean instantiation
	 * issues.
	 */
	static class Registrar implements ImportBeanDefinitionRegistrar {

		private static final String BEAN_NAME = "dataSourceInitializerPostProcessor";

		@Override
		public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
				BeanDefinitionRegistry registry) {
			if (!registry.containsBeanDefinition(BEAN_NAME)) {
				GenericBeanDefinition beanDefinition = new GenericBeanDefinition();
				beanDefinition.setBeanClass(DataSourceInitializerPostProcessor.class);
				beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
				// We don't need this one to be post processed otherwise it can cause a
				// cascade of bean instantiation that we would rather avoid.
				beanDefinition.setSynthetic(true);
				registry.registerBeanDefinition(BEAN_NAME, beanDefinition);
			}
		}

	}

}