/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.service;

A registry of services. 
Author:
Steve Ebersole/**
 * A registry of {@link Service services}.
 *
 * @author Steve Ebersole
 */
public interface ServiceRegistry {
	
Retrieve this registry's parent registry.
Returns:
The parent registry.  May be null./**
	 * Retrieve this registry's parent registry.
	 * 
	 * @return The parent registry.  May be null.
	 */
	public ServiceRegistry getParentServiceRegistry();

	
Retrieve a service by role. If service is not found, but a ServiceInitiator is registered for this service role, the service will be initialized and returned. 
 NOTE: We cannot return <R extends Service<T>> here because the service might come from the parent... 
Params:
serviceRole – The service role
Type parameters:
<R> – The service role type
Throws:
UnknownServiceException – Indicates the service was not known.
Returns:
The requested service./**
	 * Retrieve a service by role.  If service is not found, but a {@link org.hibernate.service.spi.ServiceInitiator} is
	 * registered for this service role, the service will be initialized and returned.
	 * <p/>
	 * NOTE: We cannot return {@code <R extends Service<T>>} here because the service might come from the parent...
	 * 
	 * @param serviceRole The service role
	 * @param <R> The service role type
	 *
	 * @return The requested service.
	 *
	 * @throws UnknownServiceException Indicates the service was not known.
	 */
	public <R extends Service> R getService(Class<R> serviceRole);
}