/*
    * Copyright 2001-2008 The Apache Software Foundation.
    * 
    * 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.apache.juddi.config;
  
  import java.util.Properties;
  
  import javax.persistence.EntityManagerFactory;
  import javax.persistence.Persistence;
  import javax.persistence.EntityManager;
  
  import org.apache.commons.configuration.ConfigurationException;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  public class PersistenceManager {
  	private static Log log = LogFactory.getLog(PersistenceManager.class);
  	
  	public static final String PERSISTENCE_UNIT_NAME = "juddiDatabase";
  
  	private static EntityManagerFactory emf;
  
  	public static EntityManager getEntityManager() {
  		try {
  			// Now, the factory will be initialized in the config. This will force the config to initialize, thereby initializing emf.
  			if (emf == null)
  				AppConfig.getInstance();
  		} 
  		catch (ConfigurationException e) {
  			log.error("Error initializing config in PersistenceManager", e);
  			throw new ExceptionInInitializerError(e);
  		}
  		
  		return emf.createEntityManager();
  	}
  	
  	public static void closeEntityManager() {
  		if (emf.isOpen())
  			emf.close();
  	}
  	
  	protected static void initializeEntityManagerFactory(String persistenceUnitName, Properties properties) {
  		try {
  			if (emf == null)
  				if (properties==null || properties.size()==0) {
  					emf = Persistence.createEntityManagerFactory(persistenceUnitName);
  				} else {
  					emf = Persistence.createEntityManagerFactory(persistenceUnitName, properties);
  				}
  		}
  		catch (Throwable t) {
  			log.error("entityManagerFactory creation failed", t);
  			throw new ExceptionInInitializerError(t);
  		}
  		
  	}
  	
  }