/*
 * Copyright (c) OSGi Alliance (2009). All Rights Reserved.
 * 
 * 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.osgi.service.jpa;

import java.util.Map;

import javax.persistence.EntityManagerFactory;

/**
 * This service interface offers JPA clients the ability to create instances of
 * EntityManagerFactory for a given named persistence unit. A service instance  
 * will be created for each named persistence unit and can be filtered on by 
 * comparing the value of the osgi.unit.name property containing the persistence 
 * unit name. 
 * 
 * This service is used specifically when the caller wants to pass in factory-scoped
 * properties as arguments. If no properties are being used in the creation of the 
 * EntityManagerFactory then the basic EntityManagerFactory service should be used.
 */
public interface EntityManagerFactoryBuilder {

    /**
     * The name of the persistence unit.
     */
    public static final String JPA_UNIT_NAME = "osgi.unit.name";

    /**
     * The version of the persistence unit bundle.
     */
    public static final String JPA_UNIT_VERSION = "osgi.unit.version";

    /**
     * The class name of the provider that registered the service and implements 
     * the JPA javax.persistence.PersistenceProvider interface.
     */
    public static final String JPA_UNIT_PROVIDER = "osgi.unit.provider";

	/**
	 * Return an EntityManagerFactory instance configured according to the properties
     * defined in the corresponding persistence descriptor, as well as the properties 
     * passed into the method.
	 * 
	 * @param props Properties to be used, in addition to those in the persistence descriptor,
     *              for configuring the EntityManagerFactory for the persistence unit.
     *
	 * @return An EntityManagerFactory for the persistence unit associated with this service.
	 */
    @SuppressWarnings("unchecked")
    EntityManagerFactory createEntityManagerFactory(Map props);
}