Marcel Offermans | 516d38d | 2006-03-25 20:46:19 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2006 The Apache Software Foundation |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | * |
| 16 | */ |
| 17 | package org.apache.felix.dependencymanager; |
| 18 | |
| 19 | import java.util.List; |
| 20 | |
| 21 | import org.osgi.framework.BundleActivator; |
| 22 | import org.osgi.framework.BundleContext; |
| 23 | |
| 24 | /** |
| 25 | * Base bundle activator class. Subclass this activator if you want to use dependency |
| 26 | * management in your bundle. There are two methods you should implement: |
| 27 | * <code>init()</code> and <code>destroy()</code>. Both methods take two arguments, |
| 28 | * the bundle context and the dependency manager. The dependency manager can be used |
| 29 | * to define all the dependencies. |
| 30 | * |
| 31 | * @author Marcel Offermans |
| 32 | */ |
| 33 | public abstract class DependencyActivatorBase implements BundleActivator { |
| 34 | private BundleContext m_context; |
| 35 | private DependencyManager m_manager; |
| 36 | |
| 37 | /** |
| 38 | * Initialize the dependency manager. Here you can add all services and their dependencies. |
| 39 | * If something goes wrong and you do not want your bundle to be started, you can throw an |
| 40 | * exception. This exception will be passed on to the <code>start()</code> method of the |
| 41 | * bundle activator, causing the bundle not to start. |
| 42 | * |
| 43 | * @param context the bundle context |
| 44 | * @param manager the dependency manager |
| 45 | * @throws Exception if the initialization fails |
| 46 | */ |
| 47 | public abstract void init(BundleContext context, DependencyManager manager) throws Exception; |
| 48 | |
| 49 | /** |
| 50 | * Destroy the dependency manager. Here you can remove all services and their dependencies. |
| 51 | * Actually, the base class will clean up your dependencies anyway, so most of the time you |
| 52 | * don't need to do anything here. |
| 53 | * If something goes wrong and you do not want your bundle to be stopped, you can throw an |
| 54 | * exception. This exception will be passed on to the <code>stop()</code> method of the |
| 55 | * bundle activator, causing the bundle not to stop. |
| 56 | * |
| 57 | * @param context the bundle context |
| 58 | * @param manager the dependency manager |
| 59 | * @throws Exception if the destruction fails |
| 60 | */ |
| 61 | public abstract void destroy(BundleContext context, DependencyManager manager) throws Exception; |
| 62 | |
| 63 | /** |
| 64 | * Start method of the bundle activator. Initializes the dependency manager |
| 65 | * and calls <code>init()</code>. |
| 66 | * |
| 67 | * @param context the bundle context |
| 68 | */ |
| 69 | public void start(BundleContext context) throws Exception { |
| 70 | m_context = context; |
| 71 | m_manager = new DependencyManager(context); |
| 72 | init(m_context, m_manager); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Stop method of the bundle activator. Calls the <code>destroy()</code> method |
| 77 | * and cleans up all left over dependencies. |
| 78 | * |
| 79 | * @param context the bundle context |
| 80 | */ |
| 81 | public void stop(BundleContext context) throws Exception { |
| 82 | destroy(m_context, m_manager); |
| 83 | cleanup(m_manager); |
| 84 | m_manager = null; |
| 85 | m_context = null; |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Creates a new service. |
| 90 | * |
| 91 | * @return the new service |
| 92 | */ |
| 93 | public Service createService() { |
| 94 | return new ServiceImpl(m_context); |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Creates a new service dependency. |
| 99 | * |
| 100 | * @return the service dependency |
| 101 | */ |
| 102 | public ServiceDependency createServiceDependency() { |
| 103 | return new ServiceDependency(m_context); |
| 104 | } |
| 105 | |
| 106 | /** |
| 107 | * Cleans up all services and their dependencies. |
| 108 | * |
| 109 | * @param manager the dependency manager |
| 110 | */ |
| 111 | private void cleanup(DependencyManager manager) { |
| 112 | List services = manager.getServices(); |
| 113 | for (int i = services.size() - 1; i >= 0; i--) { |
| 114 | Service service = (Service) services.get(i); |
| 115 | manager.remove(service); |
| 116 | // remove any state listeners that are still registered |
| 117 | if (service instanceof ServiceImpl) { |
| 118 | ServiceImpl si = (ServiceImpl) service; |
| 119 | si.removeStateListeners(); |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | } |