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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  
17  package net.sf.ehcache.store;
18  
19  import java.util.Set;
20  
21  import net.sf.ehcache.Element;
22  
23  /***
24   * Use for internal purpose only. Teaser: Stores of Terracotta clustered caches implements this interface.
25   * 
26   * @author Abhishek Sanoujam
27   * 
28   */
29  public interface TerracottaStore extends Store {
30  
31      /***
32       * Returns the local value associated with the key. Local value means that the object mapped to the key is present in the VM locally. In
33       * case its not, will return null. Note that even when returning null, the value may be present in the Terracotta server array.
34       * <p/>
35       * This operation does not acquire any locks when doing the operation and may return stale values.
36       * 
37       * @param key
38       *            the key
39       * @return the element associated with key or null
40       */
41      public Element unsafeGet(Object key);
42  
43      /***
44       * Same as {@link #unsafeGet(Object)} but does not update last usage statistics
45       * 
46       * @param key
47       *            the key
48       * @return the element associated with key or null
49       */
50      public Element unsafeGetQuiet(Object key);
51  
52      /***
53       * Gets the value associated with the key without acquiring any locks. This may return stale values as locks are not acquired.
54       * 
55       * @param key
56       * @return the element associated with the key or null
57       */
58      public Element unlockedGet(Object key);
59  
60      /***
61       * Same as {@link #unlockedGet(Object)} but does not update statistics
62       * 
63       * @param key
64       * @return the element associated with the key or null
65       */
66      public Element unlockedGetQuiet(Object key);
67      
68      
69      /***
70       * Returns set of keys from the cache which are present in the node locally.
71       * @return set of keys present locally in the node
72       */
73      public Set getLocalKeys();
74  
75  }