View Javadoc

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.util;
21  
22  import org.apache.hadoop.classification.InterfaceAudience;
23  import org.apache.hadoop.hbase.KeyValue;
24  import org.apache.hadoop.hbase.KeyValue.KVComparator;
25  import org.apache.hadoop.hbase.KeyValueUtil;
26  
27  @InterfaceAudience.Private
28  public class CompoundBloomFilterBase implements BloomFilterBase {
29  
30    /**
31     * At read time, the total number of chunks. At write time, the number of
32     * chunks created so far. The first chunk has an ID of 0, and the current
33     * chunk has the ID of numChunks - 1.
34     */
35    protected int numChunks;
36  
37    /**
38     * The Bloom filter version. There used to be a DynamicByteBloomFilter which
39     * had version 2.
40     */
41    public static final int VERSION = 3;
42  
43    /** Target error rate for configuring the filter and for information */
44    protected float errorRate;
45  
46    /** The total number of keys in all chunks */
47    protected long totalKeyCount;
48    protected long totalByteSize;
49    protected long totalMaxKeys;
50  
51    /** Hash function type to use, as defined in {@link Hash} */
52    protected int hashType;
53    
54    /** Comparator used to compare Bloom filter keys */
55    protected KVComparator comparator;
56  
57    @Override
58    public long getMaxKeys() {
59      return totalMaxKeys;
60    }
61  
62    @Override
63    public long getKeyCount() {
64      return totalKeyCount;
65    }
66  
67    @Override
68    public long getByteSize() {
69      return totalByteSize;
70    }
71  
72    private static final byte[] DUMMY = new byte[0];
73  
74    /**
75     * Prepare an ordered pair of row and qualifier to be compared using
76     * KeyValue.KeyComparator. This is only used for row-column Bloom
77     * filters.
78     */
79    @Override
80    public byte[] createBloomKey(byte[] row, int roffset, int rlength,
81        byte[] qualifier, int qoffset, int qlength) {
82      if (qualifier == null)
83        qualifier = DUMMY;
84  
85      // Make sure this does not specify a timestamp so that the default maximum
86      // (most recent) timestamp is used.
87      KeyValue kv = KeyValueUtil.createFirstOnRow(row, roffset, rlength, DUMMY, 0, 0,
88          qualifier, qoffset, qlength);
89      return kv.getKey();
90    }
91  
92    @Override
93    public KVComparator getComparator() {
94      return comparator;
95    }
96  
97  }