/*
    * Copyright 2007 The Kuali Foundation
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
    *
   * 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.kuali.rice.core.ojb;
  
  import java.sql.Connection;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  
  import javax.sql.DataSource;
  
  import org.apache.ojb.broker.accesslayer.ConnectionFactoryNotPooledImpl;
  import org.apache.ojb.broker.accesslayer.LookupException;
  import org.apache.ojb.broker.metadata.JdbcConnectionDescriptor;
  import org.springframework.beans.factory.BeanFactory;
  import org.springframework.jdbc.datasource.TransactionAwareDataSourceProxy;
  
  public class RiceDataSourceConnectionFactory extends ConnectionFactoryNotPooledImpl {
  
  	/**
  	 * BeanFactories to retrieve DataSource beans from.
  	 */
  	private static List<BeanFactory> beanFactories = new ArrayList<BeanFactory>();
  
  	public static void addBeanFactory(BeanFactory beanFactory) {
  		beanFactories.add(beanFactory);
  	}
  
  	/**
  	 * Map that holds already retrieved DataSources,
  	 * with JCD alias Strings as keys and DataSources as values.
  	 */
  	private Map<String, DataSource> dataSources = new HashMap<String, DataSource>();
  
  	public RiceDataSourceConnectionFactory() {
  		if (beanFactories.isEmpty()) {
  			throw new IllegalStateException("No BeanFactories found for configuration - must specify RiceOjbConfigurer as a Spring bean.");
  		}
  	}
  
  	public Connection lookupConnection(JdbcConnectionDescriptor jcd) throws LookupException {
  		try {
  			DataSource dataSource = null;
  			synchronized (this.dataSources) {
  				dataSource = this.dataSources.get(jcd.getJcdAlias());
  				if (dataSource == null) {
  					dataSource = getDataSource(jcd.getJcdAlias());
  					this.dataSources.put(jcd.getJcdAlias(), dataSource);
  				}
  			}
  			return dataSource.getConnection();
  		}
  		catch (Exception ex) {
  			throw new LookupException("Could not obtain connection from data source", ex);
  		}
  	}
  
  	/**
  	 * Return the DataSource to use for the given JCD alias.
  	 * <p>This implementation fetches looks for a bean with the
  	 * JCD alias name in the provided Spring BeanFactory.
  	 * @param jcdAlias the JCD alias to retrieve a DataSource for
  	 * @return the DataSource to use
  	 */
  
  	protected DataSource getDataSource(String jcdAlias) throws LookupException {
  		DataSource dataSource = null;
  		for (BeanFactory beanFactory : beanFactories) {
  			if (beanFactory.containsBean(jcdAlias)) {
  				dataSource = (DataSource) beanFactory.getBean(jcdAlias, DataSource.class);
  				break;
  			}
  		}
  		if (dataSource == null) {
  			throw new LookupException("Could not lookup datasource with alias " + jcdAlias);
  		} else if (dataSource instanceof TransactionAwareDataSourceProxy) {
  			return dataSource;
  		} else {
  			return new TransactionAwareDataSourceProxy(dataSource);
  		}
  	}
  
  }