1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 * 19 */ 20 21 package org.apache.directory.mavibot.btree; 22 23 24 import java.util.Comparator; 25 26 27 /** 28 * An comparator that encapsulate a Comparator to compare two tuples 29 * using their key. 30 * 31 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 32 */ 33 public class TupleComparator<K, V> implements Comparator<Tuple<K, V>> 34 { 35 /** the embedded Comparator to use for the key comparison */ 36 Comparator<K> keyComparator; 37 38 /** the embedded Comparator to use for the value comparison */ 39 Comparator<V> valueComparator; 40 41 42 /** 43 * Creates a new instance of TupleComparator. 44 * 45 * @param keyComparator The inner key comparator 46 * @param valueComparator The inner value comparator 47 */ 48 public TupleComparator( Comparator<K> keyComparator, Comparator<V> valueComparator ) 49 { 50 this.keyComparator = keyComparator; 51 } 52 53 54 /** 55 * Compare two tuples. We compare the keys only. 56 * 57 * @param t1 The first tuple 58 * @param t2 The second tuple 59 * @return There are 5 possible results : 60 * <ul> 61 * <li>-1 : the first key is below the second key </li> 62 * <li>0 : the two keys are equals, keys and values</li> 63 * <li>1 : the first key is above the second key</li> 64 * </ul> 65 */ 66 @Override 67 public int compare( Tuple<K, V> t1, Tuple<K, V> t2 ) 68 { 69 return keyComparator.compare( t1.key, t2.key ); 70 } 71 }