001    /*
002     * Copyright (c) OSGi Alliance (2001, 2008). All Rights Reserved.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *      http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package org.osgi.service.device;
017    
018    import org.osgi.framework.ServiceReference;
019    
020    /**
021     * When the device manager detects a new Device service, it calls all registered
022     * Driver services to determine if anyone matches the Device service. If at
023     * least one Driver service matches, the device manager must choose one. If
024     * there is a Driver Selector service registered with the Framework, the device
025     * manager will ask it to make the selection. If there is no Driver Selector
026     * service, or if it returns an invalid result, or throws an
027     * <code>Exception</code>, the device manager uses the default selection
028     * strategy.
029     * 
030     * @version $Revision: 5654 $
031     * @since 1.1
032     * @ThreadSafe
033     */
034    public interface DriverSelector {
035            /**
036             * Return value from <code>DriverSelector.select</code>, if no Driver
037             * service should be attached to the Device service. The value is -1.
038             */
039            public static final int SELECT_NONE     = -1;
040    
041            /**
042             * Select one of the matching Driver services. The device manager calls this
043             * method if there is at least one driver bidding for a device. Only Driver
044             * services that have responded with nonzero (not {@link Device#MATCH_NONE})
045             * <code></code> match values will be included in the list.
046             * 
047             * @param reference the <code>ServiceReference</code> object of the Device
048             *        service.
049             * @param matches the array of all non-zero matches.
050             * @return index into the array of <code>Match</code> objects, or
051             *         <code>SELECT_NONE</code> if no Driver service should be attached
052             */
053            public int select(ServiceReference reference, Match[] matches);
054    }