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.Comparator;
24
25
26 /**
27 * A comparator for the RevisionName class
28 *
29 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
30 */
31 /* no qualifier*/class RevisionNameComparator implements Comparator<RevisionName>
32 {
33 /** A static instance of a RevisionNameComparator */
34 public static final RevisionNameComparator INSTANCE = new RevisionNameComparator();
35
36 /**
37 * A private constructor of the RevisionNameComparator class
38 */
39 private RevisionNameComparator()
40 {
41 }
42
43
44 /**
45 * {@inheritDoc}
46 */
47 public int compare( RevisionName rn1, RevisionName rn2 )
48 {
49 if ( rn1 == rn2 )
50 {
51 return 0;
52 }
53
54 // First compare the revisions
55 if ( rn1.getRevision() < rn2.getRevision() )
56 {
57 return -1;
58 }
59 else if ( rn1.getRevision() > rn2.getRevision() )
60 {
61 return 1;
62 }
63
64 // The revision are equal : check the name
65 return rn1.getName().compareTo( rn2.getName() );
66 }
67 }