View Javadoc

1   /**
2    * Copyright 2011 The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  
21  package org.apache.hadoop.hbase.io.hfile.slab;
22  
23  import org.apache.hadoop.hbase.io.hfile.BlockCacheKey;
24  
25  /**
26   * Interface for objects that want to know when actions occur in a SingleSizeCache.
27   * */
28  interface SlabItemActionWatcher {
29  
30    /**
31     * This is called as a callback when an item is removed from a SingleSizeCache.
32     *
33     * @param key the key of the item being evicted
34     * @param notifier the object notifying the SlabCache of the eviction.
35     */
36    void onEviction(BlockCacheKey key, SingleSizeCache notifier);
37    
38    /**
39     * This is called as a callback when an item is inserted into a SingleSizeCache.
40     *
41     * @param key the key of the item being added
42     * @param notifier the object notifying the SlabCache of the insertion..
43     */
44    void onInsertion(BlockCacheKey key, SingleSizeCache notifier);
45  }