| /* |
| * Copyright (c) OSGi Alliance (2000, 2010). 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.framework; |
| |
| /** |
| * Allows services to provide customized service objects in the OSGi |
| * environment. |
| * |
| * <p> |
| * When registering a service, a {@code ServiceFactory} object can be used |
| * instead of a service object, so that the bundle developer can gain control of |
| * the specific service object granted to a bundle that is using the service. |
| * |
| * <p> |
| * When this happens, the |
| * {@code BundleContext.getService(ServiceReference)} method calls the |
| * {@code ServiceFactory.getService} method to create a service object |
| * specifically for the requesting bundle. The service object returned by the |
| * {@code ServiceFactory} is cached by the Framework until the bundle |
| * releases its use of the service. |
| * |
| * <p> |
| * When the bundle's use count for the service equals zero (including the bundle |
| * stopping or the service being unregistered), the |
| * {@code ServiceFactory.ungetService} method is called. |
| * |
| * <p> |
| * {@code ServiceFactory} objects are only used by the Framework and are |
| * not made available to other bundles in the OSGi environment. The Framework |
| * may concurrently call a {@code ServiceFactory}. |
| * |
| * @param <S> Type of Service |
| * @see BundleContext#getService |
| * @ThreadSafe |
| * @version $Id: 6dad978a4354eedf8a4317b4aac37f2f2315d093 $ |
| */ |
| |
| public interface ServiceFactory<S> { |
| /** |
| * Creates a new service object. |
| * |
| * <p> |
| * The Framework invokes this method the first time the specified |
| * {@code bundle} requests a service object using the |
| * {@code BundleContext.getService(ServiceReference)} method. The |
| * service factory can then return a specific service object for each |
| * bundle. |
| * |
| * <p> |
| * The Framework caches the value returned (unless it is {@code null}), |
| * and will return the same service object on any future call to |
| * {@code BundleContext.getService} for the same bundle. This means the |
| * Framework must not allow this method to be concurrently called for the |
| * same bundle. |
| * |
| * <p> |
| * The Framework will check if the returned service object is an instance of |
| * all the classes named when the service was registered. If not, then |
| * {@code null} is returned to the bundle. |
| * |
| * @param bundle The bundle using the service. |
| * @param registration The {@code ServiceRegistration} object for the |
| * service. |
| * @return A service object that <strong>must</strong> be an instance of all |
| * the classes named when the service was registered. |
| * @see BundleContext#getService |
| */ |
| public S getService(Bundle bundle, ServiceRegistration<S> registration); |
| |
| /** |
| * Releases a service object. |
| * |
| * <p> |
| * The Framework invokes this method when a service has been released by a |
| * bundle. The service object may then be destroyed. |
| * |
| * @param bundle The bundle releasing the service. |
| * @param registration The {@code ServiceRegistration} object for the |
| * service. |
| * @param service The service object returned by a previous call to the |
| * {@code ServiceFactory.getService} method. |
| * @see BundleContext#ungetService |
| */ |
| public void ungetService(Bundle bundle, ServiceRegistration<S> registration, |
| S service); |
| } |