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 package org.apache.directory.mavibot.btree; 21 22 23 import java.util.Arrays; 24 import java.util.Comparator; 25 26 27 /** 28 * A comparator for the RevisionOffset class 29 * 30 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 31 */ 32 /* no qualifier*/class RevisionOffsetComparator implements Comparator<RevisionOffset> 33 { 34 /** A static instance of a RevisionOffsetComparator */ 35 public static final RevisionOffsetComparator INSTANCE = new RevisionOffsetComparator(); 36 37 public static final RevisionOffsetComparator INSTANCE_DESC_ORDER = new RevisionOffsetComparator( true ); 38 39 private boolean desc; 40 41 /** 42 * A private constructor of the RevisionOffsetComparator class 43 */ 44 private RevisionOffsetComparator() 45 { 46 } 47 48 49 private RevisionOffsetComparator( boolean desc ) 50 { 51 this.desc = desc; 52 } 53 54 55 /** 56 * {@inheritDoc} 57 */ 58 public int compare( RevisionOffset rn1, RevisionOffset rn2 ) 59 { 60 if ( rn1 == rn2 ) 61 { 62 return 0; 63 } 64 65 // the RevisionOffset will never be used as a key 66 67 // First compare the revisions 68 if ( rn1.getRevision() < rn2.getRevision() ) 69 { 70 return desc ? 1 : -1; 71 } 72 else if ( rn1.getRevision() > rn2.getRevision() ) 73 { 74 return desc ? -1 : 1; 75 } 76 77 // ignore the offsets 78 return 0; 79 } 80 }