| /* |
| * $Header: /cvshome/build/org.osgi.util.tracker/src/org/osgi/util/tracker/ServiceTrackerCustomizer.java,v 1.13 2007/02/19 19:04:33 hargrave Exp $ |
| * |
| * Copyright (c) OSGi Alliance (2000, 2007). 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.util.tracker; |
| |
| import org.osgi.framework.ServiceReference; |
| |
| /** |
| * The <code>ServiceTrackerCustomizer</code> interface allows a |
| * <code>ServiceTracker</code> object to customize the service objects that |
| * are tracked. The <code>ServiceTrackerCustomizer</code> object is called |
| * when a service is being added to the <code>ServiceTracker</code> object. |
| * The <code>ServiceTrackerCustomizer</code> can then return an object for the |
| * tracked service. The <code>ServiceTrackerCustomizer</code> object is also |
| * called when a tracked service is modified or has been removed from the |
| * <code>ServiceTracker</code> object. |
| * |
| * <p> |
| * The methods in this interface may be called as the result of a |
| * <code>ServiceEvent</code> being received by a <code>ServiceTracker</code> |
| * object. Since <code>ServiceEvent</code> s are synchronously delivered by |
| * the Framework, it is highly recommended that implementations of these methods |
| * do not register (<code>BundleContext.registerService</code>), modify ( |
| * <code>ServiceRegistration.setProperties</code>) or unregister ( |
| * <code>ServiceRegistration.unregister</code>) a service while being |
| * synchronized on any object. |
| * |
| * <p> |
| * The <code>ServiceTracker</code> class is thread-safe. It does not call a |
| * <code>ServiceTrackerCustomizer</code> object while holding any locks. |
| * <code>ServiceTrackerCustomizer</code> implementations must also be |
| * thread-safe. |
| * |
| * @ThreadSafe |
| * @version $Revision: 1.13 $ |
| */ |
| public interface ServiceTrackerCustomizer { |
| /** |
| * A service is being added to the <code>ServiceTracker</code> object. |
| * |
| * <p> |
| * This method is called before a service which matched the search |
| * parameters of the <code>ServiceTracker</code> object is added to it. |
| * This method should return the service object to be tracked for this |
| * <code>ServiceReference</code> object. The returned service object is |
| * stored in the <code>ServiceTracker</code> object and is available from |
| * the <code>getService</code> and <code>getServices</code> methods. |
| * |
| * @param reference Reference to service being added to the |
| * <code>ServiceTracker</code> object. |
| * @return The service object to be tracked for the |
| * <code>ServiceReference</code> object or <code>null</code> if |
| * the <code>ServiceReference</code> object should not be tracked. |
| */ |
| public Object addingService(ServiceReference reference); |
| |
| /** |
| * A service tracked by the <code>ServiceTracker</code> object has been |
| * modified. |
| * |
| * <p> |
| * This method is called when a service being tracked by the |
| * <code>ServiceTracker</code> object has had it properties modified. |
| * |
| * @param reference Reference to service that has been modified. |
| * @param service The service object for the modified service. |
| */ |
| public void modifiedService(ServiceReference reference, Object service); |
| |
| /** |
| * A service tracked by the <code>ServiceTracker</code> object has been |
| * removed. |
| * |
| * <p> |
| * This method is called after a service is no longer being tracked by the |
| * <code>ServiceTracker</code> object. |
| * |
| * @param reference Reference to service that has been removed. |
| * @param service The service object for the removed service. |
| */ |
| public void removedService(ServiceReference reference, Object service); |
| } |