/*
 * Copyright 2002-2017 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.jdbc.datasource.lookup;

import javax.sql.DataSource;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

DataSourceLookup implementation based on a Spring BeanFactory. 
Will lookup Spring managed beans identified by bean name, expecting them to be of type javax.sql.DataSource. 
Author:
Costin Leau, Juergen Hoeller
See Also:
BeanFactory
Since:
2.0/**
 * {@link DataSourceLookup} implementation based on a Spring {@link BeanFactory}.
 *
 * <p>Will lookup Spring managed beans identified by bean name,
 * expecting them to be of type {@code javax.sql.DataSource}.
 *
 * @author Costin Leau
 * @author Juergen Hoeller
 * @since 2.0
 * @see org.springframework.beans.factory.BeanFactory
 */
public class BeanFactoryDataSourceLookup implements DataSourceLookup, BeanFactoryAware {

	@Nullable
	private BeanFactory beanFactory;


	
Create a new instance of the BeanFactoryDataSourceLookup class. 
The BeanFactory to access must be set via setBeanFactory. 
See Also:
setBeanFactory/**
	 * Create a new instance of the {@link BeanFactoryDataSourceLookup} class.
	 * <p>The BeanFactory to access must be set via {@code setBeanFactory}.
	 * @see #setBeanFactory
	 */
	public BeanFactoryDataSourceLookup() {
	}

	
Create a new instance of the BeanFactoryDataSourceLookup class. 
Use of this constructor is redundant if this object is being created by a Spring IoC container, as the supplied BeanFactory will be replaced by the BeanFactory that creates it (c.f. the BeanFactoryAware contract). So only use this constructor if you are using this class outside the context of a Spring IoC container. 
Params:
beanFactory – the bean factory to be used to lookup DataSources/**
	 * Create a new instance of the {@link BeanFactoryDataSourceLookup} class.
	 * <p>Use of this constructor is redundant if this object is being created
	 * by a Spring IoC container, as the supplied {@link BeanFactory} will be
	 * replaced by the {@link BeanFactory} that creates it (c.f. the
	 * {@link BeanFactoryAware} contract). So only use this constructor if you
	 * are using this class outside the context of a Spring IoC container.
	 * @param beanFactory the bean factory to be used to lookup {@link DataSource DataSources}
	 */
	public BeanFactoryDataSourceLookup(BeanFactory beanFactory) {
		Assert.notNull(beanFactory, "BeanFactory is required");
		this.beanFactory = beanFactory;
	}


	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
	}


	@Override
	public DataSource getDataSource(String dataSourceName) throws DataSourceLookupFailureException {
		Assert.state(this.beanFactory != null, "BeanFactory is required");
		try {
			return this.beanFactory.getBean(dataSourceName, DataSource.class);
		}
		catch (BeansException ex) {
			throw new DataSourceLookupFailureException(
					"Failed to look up DataSource bean with name '" + dataSourceName + "'", ex);
		}
	}

}