001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020 021package org.apache.directory.mavibot.btree; 022 023 024import java.util.Comparator; 025 026 027/** 028 * An comparator that encapsulate a Comparator to compare two tuples 029 * using their key. 030 * 031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 032 */ 033public class TupleComparator<K, V> implements Comparator<Tuple<K, V>> 034{ 035 /** the embedded Comparator to use for the key comparison */ 036 Comparator<K> keyComparator; 037 038 /** the embedded Comparator to use for the value comparison */ 039 Comparator<V> valueComparator; 040 041 042 /** 043 * Creates a new instance of TupleComparator. 044 * 045 * @param keyComparator The inner key comparator 046 * @param valueComparator The inner value comparator 047 */ 048 public TupleComparator( Comparator<K> keyComparator, Comparator<V> valueComparator ) 049 { 050 this.keyComparator = keyComparator; 051 } 052 053 054 /** 055 * Compare two tuples. We compare the keys only. 056 * 057 * @param t1 The first tuple 058 * @param t2 The second tuple 059 * @return There are 5 possible results : 060 * <ul> 061 * <li>-1 : the first key is below the second key </li> 062 * <li>0 : the two keys are equals, keys and values</li> 063 * <li>1 : the first key is above the second key</li> 064 * </ul> 065 */ 066 @Override 067 public int compare( Tuple<K, V> t1, Tuple<K, V> t2 ) 068 { 069 return keyComparator.compare( t1.key, t2.key ); 070 } 071}