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.Dictionary; |
| 20 | import java.util.List; |
| 21 | |
| 22 | import org.osgi.framework.ServiceRegistration; |
| 23 | |
| 24 | /** |
| 25 | * Service interface. |
| 26 | * |
| 27 | * @author Marcel Offermans |
| 28 | */ |
| 29 | public interface Service { |
| 30 | /** |
| 31 | * Adds a new dependency to this service. |
| 32 | * |
| 33 | * @param dependency the dependency to add |
| 34 | * @return this service |
| 35 | */ |
| 36 | public Service add(Dependency dependency); |
| 37 | |
| 38 | /** |
| 39 | * Removes a dependency from this service. |
| 40 | * |
| 41 | * @param dependency the dependency to remove |
| 42 | * @return this service |
| 43 | */ |
| 44 | public Service remove(Dependency dependency); |
| 45 | |
| 46 | /** |
| 47 | * Sets the public interface under which this service should be registered |
| 48 | * in the OSGi service registry. |
| 49 | * |
| 50 | * @param serviceName the name of the service interface |
| 51 | * @param properties the properties for this service |
| 52 | * @return this service |
| 53 | */ |
| 54 | public Service setInterface(String serviceName, Dictionary properties); |
| 55 | /** |
| 56 | * Sets the public interfaces under which this service should be registered |
| 57 | * in the OSGi service registry. |
| 58 | * |
| 59 | * @param serviceNames the names of the service interface |
| 60 | * @param properties the properties for this service |
| 61 | * @return this service |
| 62 | */ |
| 63 | public Service setInterface(String[] serviceNames, Dictionary properties); |
| 64 | |
| 65 | /** |
| 66 | * Sets the implementation for this service. You can actually specify |
| 67 | * an instance you have instantiated manually, or a <code>Class</code> |
| 68 | * that will be instantiated using its default constructor when the |
| 69 | * required dependencies are resolved (effectively giving you a lazy |
| 70 | * instantiation mechanism). |
| 71 | * |
| 72 | * There are four special methods that are called when found through |
| 73 | * reflection to give you some life-cycle management options: |
| 74 | * <ol> |
| 75 | * <li><code>init()</code> when the implementation should be initialized, |
| 76 | * before it is actually registered as a service (if at all)</li> |
| 77 | * <li><code>start()</code> when the implementation has been registered |
| 78 | * as a service (if at all)</li> |
| 79 | * <li><code>stop()</code> when the implementation will be stopped, just |
| 80 | * before the service will go away (if it had been registered)</li> |
| 81 | * <li><code>destroy()</code>after the service has gone away (if it had |
| 82 | * been registered)</li> |
| 83 | * </ol> |
| 84 | * In short, this allows you to initialize your instance before it is |
| 85 | * registered, perform some post-initialization and pre-destruction code |
| 86 | * as well as final cleanup. If a method is not defined, it simply is not |
| 87 | * called, so you can decide which one(s) you need. |
| 88 | * |
| 89 | * @param implementation the implementation |
| 90 | * @return this service |
| 91 | */ |
| 92 | public Service setImplementation(Object implementation); |
| 93 | |
| 94 | /** |
| 95 | * Returns a list of dependencies. |
| 96 | * |
| 97 | * @return a list of dependencies |
| 98 | */ |
| 99 | public List getDependencies(); |
| 100 | |
| 101 | /** |
| 102 | * Returns the service registration for this service. The method |
| 103 | * will return <code>null</code> if no service registration is |
| 104 | * available. |
| 105 | * |
| 106 | * @return the service registration |
| 107 | */ |
| 108 | public ServiceRegistration getServiceRegistration(); |
| 109 | |
| 110 | /** |
| 111 | * Returns the service instance for this service. The method will |
| 112 | * return <code>null</code> if no service instance is available. |
| 113 | * |
| 114 | * @return the service instance |
| 115 | */ |
| 116 | public Object getService(); |
| 117 | |
| 118 | /** |
| 119 | * Returns the service properties associated with the service. |
| 120 | * |
| 121 | * @return the properties or <code>null</code> if there are none |
| 122 | */ |
| 123 | public Dictionary getServiceProperties(); |
| 124 | |
| 125 | /** |
| 126 | * Sets the service properties associated with the service. If the service |
| 127 | * was already registered, it will be updated. |
| 128 | * |
| 129 | * @param serviceProperties the properties |
| 130 | */ |
| 131 | public void setServiceProperties(Dictionary serviceProperties); |
| 132 | |
| 133 | /** |
| 134 | * Sets the names of the methods used as callbacks. These methods, when found, are |
| 135 | * invoked as part of the life-cycle management of the service implementation. The |
| 136 | * methods should not have any parameters. |
| 137 | * |
| 138 | * @param init the name of the init method |
| 139 | * @param start the name of the start method |
| 140 | * @param stop the name of the stop method |
| 141 | * @param destroy the name of the destroy method |
| 142 | * @return the service instance |
| 143 | */ |
| 144 | public Service setCallbacks(String init, String start, String stop, String destroy); |
| 145 | |
| 146 | // listener |
| 147 | /** |
| 148 | * Adds a service state listener to this service. |
| 149 | * |
| 150 | * @param listener the state listener |
| 151 | */ |
| 152 | public void addStateListener(ServiceStateListener listener); |
| 153 | |
| 154 | /** |
| 155 | * Removes a service state listener from this service. |
| 156 | * |
| 157 | * @param listener the state listener |
| 158 | */ |
| 159 | public void removeStateListener(ServiceStateListener listener); |
| 160 | |
| 161 | // events, must be fired when the dependency is started/active |
| 162 | |
| 163 | /** |
| 164 | * Will be called when the dependency becomes available. |
| 165 | * |
| 166 | * @param dependency the dependency |
| 167 | */ |
| 168 | public void dependencyAvailable(Dependency dependency); |
| 169 | |
| 170 | /** |
| 171 | * Will be called when the dependency changes. |
| 172 | * |
| 173 | * @param dependency the dependency |
| 174 | */ |
| 175 | public void dependencyUnavailable(Dependency dependency); |
| 176 | |
| 177 | /** |
| 178 | * Will be called when the dependency becomes unavailable. |
| 179 | * |
| 180 | * @param dependency the dependency |
| 181 | */ |
| 182 | public void dependencyChanged(Dependency dependency); |
| 183 | |
| 184 | /** |
| 185 | * Starts the service. This activates the dependency tracking mechanism |
| 186 | * for this service. |
| 187 | */ |
| 188 | public void start(); |
| 189 | |
| 190 | /** |
| 191 | * Stops the service. This deactivates the dependency tracking mechanism |
| 192 | * for this service. |
| 193 | */ |
| 194 | public void stop(); |
| 195 | } |