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 package org.apache.hadoop.hbase.util;
20
21 import java.nio.ByteBuffer;
22
23 import org.apache.hadoop.hbase.classification.InterfaceAudience;
24
25 /**
26 * Defines the general behavior of a bloom filter.
27 *
28 * <p>
29 * The Bloom filter is a data structure that was introduced in 1970 and that
30 * has been adopted by the networking research community in the past decade
31 * thanks to the bandwidth efficiencies that it offers for the transmission of
32 * set membership information between networked hosts. A sender encodes the
33 * information into a bit vector, the Bloom filter, that is more compact than a
34 * conventional representation. Computation and space costs for construction
35 * are linear in the number of elements. The receiver uses the filter to test
36 * whether various elements are members of the set. Though the filter will
37 * occasionally return a false positive, it will never return a false negative.
38 * When creating the filter, the sender can choose its desired point in a
39 * trade-off between the false positive rate and the size.
40 *
41 * @see BloomFilterWriter for the ability to add elements to a Bloom filter
42 */
43 @InterfaceAudience.Private
44 public interface BloomFilter extends BloomFilterBase {
45
46 /**
47 * Check if the specified key is contained in the bloom filter.
48 *
49 * @param buf data to check for existence of
50 * @param offset offset into the data
51 * @param length length of the data
52 * @param bloom bloom filter data to search. This can be null if auto-loading
53 * is supported.
54 * @return true if matched by bloom, false if not
55 */
56 boolean contains(byte [] buf, int offset, int length, ByteBuffer bloom);
57
58 /**
59 * @return true if this Bloom filter can automatically load its data
60 * and thus allows a null byte buffer to be passed to contains()
61 */
62 boolean supportsAutoLoading();
63 }