OptionalServiceCollection.java

/* ==================================================================
 * OptionalServiceCollection.java - Mar 24, 2014 1:41:25 PM
 * 
 * Copyright 2007-2014 SolarNetwork.net Dev Team
 * 
 * This program is free software; you can redistribute it and/or 
 * modify it under the terms of the GNU General Public License as 
 * published by the Free Software Foundation; either version 2 of 
 * the License, or (at your option) any later version.
 * 
 * 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 
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 
 * 02111-1307 USA
 * ==================================================================
 */

package net.solarnetwork.util;

/**
 * API for a collection of "optional" services. This API is like a simplified
 * OSGi ServiceTracker for a collection of services. Calling the
 * {@link #service()} method will return the first available matching service,
 * or <em>null</em> if none available. </p>
 * 
 * @param <T>
 *        the tracked service type
 * 
 * @author matt
 * @version 1.0
 * @see OptionalService
 */
public interface OptionalServiceCollection<T> {

	/**
	 * Get the collection of configured services.
	 * 
	 * @return the services, never <em>null</em> but could be empty
	 */
	Iterable<T> services();

}