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Main functionality for HBase
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/*
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hbase.util;

import java.nio.ByteBuffer;

import org.apache.hadoop.hbase.classification.InterfaceAudience;

/**
 * Defines the general behavior of a bloom filter.
 *
 * 
 * The Bloom filter is a data structure that was introduced in 1970 and that
 * has been adopted by the networking research community in the past decade
 * thanks to the bandwidth efficiencies that it offers for the transmission of
 * set membership information between networked hosts. A sender encodes the
 * information into a bit vector, the Bloom filter, that is more compact than a
 * conventional representation. Computation and space costs for construction
 * are linear in the number of elements. The receiver uses the filter to test
 * whether various elements are members of the set. Though the filter will
 * occasionally return a false positive, it will never return a false negative.
 * When creating the filter, the sender can choose its desired point in a
 * trade-off between the false positive rate and the size.
 *
 * @see BloomFilterWriter for the ability to add elements to a Bloom filter
 */
@InterfaceAudience.Private
public interface BloomFilter extends BloomFilterBase {

  /**
   * Check if the specified key is contained in the bloom filter.
   *
   * @param buf data to check for existence of
   * @param offset offset into the data
   * @param length length of the data
   * @param bloom bloom filter data to search. This can be null if auto-loading
   *        is supported.
   * @return true if matched by bloom, false if not
   */
  boolean contains(byte [] buf, int offset, int length, ByteBuffer bloom);

  /**
   * @return true if this Bloom filter can automatically load its data
   *         and thus allows a null byte buffer to be passed to contains()
   */
  boolean supportsAutoLoading();
}