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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.hadoop.hbase.regionserver.wal;
20  
21  import java.lang.reflect.Constructor;
22  import java.lang.reflect.InvocationTargetException;
23  import org.apache.hadoop.classification.InterfaceAudience;
24  
25  /**
26   * Context that holds the various dictionaries for compression in HLog.
27   */
28  @InterfaceAudience.Private
29  class CompressionContext {
30    final Dictionary regionDict;
31    final Dictionary tableDict;
32    final Dictionary familyDict;
33    final Dictionary qualifierDict;
34    final Dictionary rowDict;
35  
36    public CompressionContext(Class<? extends Dictionary> dictType, boolean recoveredEdits)
37    throws SecurityException, NoSuchMethodException, InstantiationException,
38        IllegalAccessException, InvocationTargetException {
39      Constructor<? extends Dictionary> dictConstructor =
40          dictType.getConstructor();
41      regionDict = dictConstructor.newInstance();
42      tableDict = dictConstructor.newInstance();
43      familyDict = dictConstructor.newInstance();
44      qualifierDict = dictConstructor.newInstance();
45      rowDict = dictConstructor.newInstance();
46      if (recoveredEdits) {
47        // This will never change
48        regionDict.init(1);
49        tableDict.init(1);
50      } else {
51        regionDict.init(Short.MAX_VALUE);
52        tableDict.init(Short.MAX_VALUE);
53      }
54      rowDict.init(Short.MAX_VALUE);
55      familyDict.init(Byte.MAX_VALUE);
56      qualifierDict.init(Byte.MAX_VALUE);
57    }
58  
59    void clear() {
60      regionDict.clear();
61      tableDict.clear();
62      familyDict.clear();
63      qualifierDict.clear();
64      rowDict.clear();
65    }
66  }