1 /**
2 *
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19
20 package org.apache.hadoop.hbase.io.hfile.slab;
21
22 import org.apache.hadoop.classification.InterfaceAudience;
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 @InterfaceAudience.Private
29 interface SlabItemActionWatcher {
30
31 /**
32 * This is called as a callback when an item is removed from a SingleSizeCache.
33 *
34 * @param key the key of the item being evicted
35 * @param notifier the object notifying the SlabCache of the eviction.
36 */
37 void onEviction(BlockCacheKey key, SingleSizeCache notifier);
38
39 /**
40 * This is called as a callback when an item is inserted into a SingleSizeCache.
41 *
42 * @param key the key of the item being added
43 * @param notifier the object notifying the SlabCache of the insertion..
44 */
45 void onInsertion(BlockCacheKey key, SingleSizeCache notifier);
46 }