1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
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 package net.sf.ehcache.cluster;
17
18 import java.util.Collection;
19 import java.util.Collections;
20 import java.util.List;
21
22 /***
23 * This is a dummy implementation of the CacheCluster (Null Object Pattern). It ignores
24 * all listeners and reports no nodes.
25 *
26 * @author Geert Bevin
27 * @since 2.0
28 */
29 public class NoopCacheCluster implements CacheCluster {
30
31 /***
32 * A singleton instance you can use rather than constructing your own.
33 */
34 public static final CacheCluster INSTANCE = new NoopCacheCluster();
35
36 /***
37 * {@inheritDoc}
38 */
39 public Collection<ClusterNode> getNodes() {
40 return Collections.emptyList();
41 }
42
43 /***
44 * Always returns the ClusterScheme.NONE
45 *
46 * @return {@link ClusterScheme#NONE}
47 */
48 public ClusterScheme getScheme() {
49 return ClusterScheme.NONE;
50 }
51
52 /***
53 * {@inheritDoc}
54 */
55 public boolean addTopologyListener(ClusterTopologyListener listener) {
56 return false;
57 }
58
59 /***
60 * {@inheritDoc}
61 */
62 public boolean removeTopologyListener(ClusterTopologyListener listener) {
63 return false;
64 }
65
66 /***
67 * {@inheritDoc}
68 */
69 public boolean isClusterOnline() {
70 return true;
71 }
72
73 /***
74 * {@inheritDoc}
75 */
76 public ClusterNode getCurrentNode() {
77 return null;
78 }
79
80 /***
81 * {@inheritDoc}
82 */
83 public ClusterNode waitUntilNodeJoinsCluster() {
84 return null;
85 }
86
87 /***
88 * {@inheritDoc}
89 */
90 public List<ClusterTopologyListener> getTopologyListeners() {
91 return Collections.EMPTY_LIST;
92 }
93 }