DriverSelector.java

/*
 * Copyright (c) OSGi Alliance (2001, 2013). 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.device;

import org.osgi.framework.ServiceReference;

/**
 * When the device manager detects a new Device service, it calls all registered
 * Driver services to determine if anyone matches the Device service. If at
 * least one Driver service matches, the device manager must choose one. If
 * there is a Driver Selector service registered with the Framework, the device
 * manager will ask it to make the selection. If there is no Driver Selector
 * service, or if it returns an invalid result, or throws an {@code Exception},
 * the device manager uses the default selection strategy.
 * 
 * @author $Id: 179ecc7fc79d13bbf5d829d64b69baccd58c4b93 $
 * @since 1.1
 * @ThreadSafe
 */
public interface DriverSelector {
	/**
	 * Return value from {@code DriverSelector.select}, if no Driver service
	 * should be attached to the Device service. The value is -1.
	 */
	public static final int	SELECT_NONE	= -1;

	/**
	 * Select one of the matching Driver services. The device manager calls this
	 * method if there is at least one driver bidding for a device. Only Driver
	 * services that have responded with nonzero (not {@link Device#MATCH_NONE})
	 * {@code } match values will be included in the list.
	 * 
	 * @param reference the {@code ServiceReference} object of the Device
	 *        service.
	 * @param matches the array of all non-zero matches.
	 * @return index into the array of {@code Match} objects, or
	 *         {@code SELECT_NONE} if no Driver service should be attached
	 */
	public int select(ServiceReference reference, Match[] matches);
}