1 /* 2 * Copyright 2010 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 package org.apache.hadoop.hbase.util; 21 22 import java.nio.ByteBuffer; 23 24 /** 25 * Defines the general behavior of a bloom filter. 26 * 27 * <p> 28 * The Bloom filter is a data structure that was introduced in 1970 and that 29 * has been adopted by the networking research community in the past decade 30 * thanks to the bandwidth efficiencies that it offers for the transmission of 31 * set membership information between networked hosts. A sender encodes the 32 * information into a bit vector, the Bloom filter, that is more compact than a 33 * conventional representation. Computation and space costs for construction 34 * are linear in the number of elements. The receiver uses the filter to test 35 * whether various elements are members of the set. Though the filter will 36 * occasionally return a false positive, it will never return a false negative. 37 * When creating the filter, the sender can choose its desired point in a 38 * trade-off between the false positive rate and the size. 39 * 40 * @see BloomFilterWriter for the ability to add elements to a Bloom filter 41 */ 42 public interface BloomFilter extends BloomFilterBase { 43 44 /** 45 * Check if the specified key is contained in the bloom filter. 46 * 47 * @param buf data to check for existence of 48 * @param offset offset into the data 49 * @param length length of the data 50 * @param bloom bloom filter data to search. This can be null if auto-loading 51 * is supported. 52 * @return true if matched by bloom, false if not 53 */ 54 boolean contains(byte [] buf, int offset, int length, ByteBuffer bloom); 55 56 /** 57 * @return true if this Bloom filter can automatically load its data 58 * and thus allows a null byte buffer to be passed to contains() 59 */ 60 boolean supportsAutoLoading(); 61 }