| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.apache.felix.dependencymanager; |
| |
| /** |
| * Generic dependency for a service. A dependency can be required or not. |
| * A dependency will be activated by the service it belongs to. The service |
| * will call the <code>start(Service service)</code> and |
| * <code>stop(Service service)</code> methods. |
| * |
| * After it has been started, a dependency must callback |
| * the associated service's <code>dependencyAvailable()</code> and |
| * <code>dependencyUnavailable()</code> |
| * methods. State changes of the dependency itself may only be made as long as |
| * the dependency is not 'active', meaning it is associated with a running service. |
| * |
| * @author <a href="mailto:dev@felix.apache.org">Felix Project Team</a> |
| */ |
| public interface Dependency { |
| /** |
| * Returns <code>true</code> if this a required dependency. Required dependencies |
| * are dependencies that must be available before the service can be activated. |
| * |
| * @return <code>true</code> if the dependency is required |
| */ |
| public boolean isRequired(); |
| |
| /** |
| * Returns <code>true</code> if the dependency is available. |
| * |
| * @return <code>true</code> if the dependency is available |
| */ |
| public boolean isAvailable(); |
| } |