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Stuart McCulloch26e7a5a2011-10-17 10:31:43 +00001/*
2 * Copyright (c) OSGi Alliance (2011). All Rights Reserved.
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
17package org.osgi.service.component.annotations;
18
19/**
20 * Policy for the {@link Reference} annotation.
21 *
22 * @version $Id$
23 */
24public enum ReferencePolicy {
25 /**
26 * The static policy is the most simple policy and is the default policy. A
27 * component instance never sees any of the dynamics. Component
28 * configurations are deactivated before any bound service for a reference
29 * having a static policy becomes unavailable. If a target service is
30 * available to replace the bound service which became unavailable, the
31 * component configuration must be reactivated and bound to the replacement
32 * service.
33 */
34 STATIC,
35 /**
36 * The dynamic policy is slightly more complex since the component
37 * implementation must properly handle changes in the set of bound services.
38 * With the dynamic policy, SCR can change the set of bound services without
39 * deactivating a component configuration. If the component uses the event
40 * strategy to access services, then the component instance will be notified
41 * of changes in the set of bound services by calls to the bind and unbind
42 * methods.
43 */
44 DYNAMIC;
45}