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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.util;
22  
23  import org.apache.hadoop.io.Writable;
24  
25  /**
26   * Specifies methods needed to add elements to a Bloom filter and serialize the
27   * resulting Bloom filter as a sequence of bytes.
28   */
29  public interface BloomFilterWriter extends BloomFilterBase {
30  
31    /** Allocate memory for the bloom filter data. */
32    void allocBloom();
33  
34    /** Compact the Bloom filter before writing metadata & data to disk. */
35    void compactBloom();
36  
37    /**
38     * Get a writable interface into bloom filter meta data.
39     *
40     * @return a writable instance that can be later written to a stream
41     */
42    Writable getMetaWriter();
43  
44    /**
45     * Get a writable interface into bloom filter data (the actual Bloom bits).
46     * Not used for compound Bloom filters.
47     *
48     * @return a writable instance that can be later written to a stream
49     */
50    Writable getDataWriter();
51  
52    /**
53     * Add the specified binary to the bloom filter.
54     *
55     * @param buf data to be added to the bloom
56     * @param offset offset into the data to be added
57     * @param len length of the data to be added
58     */
59    void add(byte[] buf, int offset, int len);
60  
61  }