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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 NameRevisionComparator implements Comparator<NameRevision>
32  {
33      /** A static instance of a NameRevisionComparator */
34      public static final NameRevisionComparator INSTANCE = new NameRevisionComparator();
35  
36      /**
37       * A private constructor of the NameRevisionComparator class
38       */
39      private NameRevisionComparator()
40      {
41      }
42  
43  
44      /**
45       * {@inheritDoc}
46       */
47      public int compare( NameRevision rn1, NameRevision rn2 )
48      {
49          if ( rn1 == rn2 )
50          {
51              return 0;
52          }
53  
54          // First compare the name
55          int comp =  rn1.getName().compareTo( rn2.getName() );
56  
57          if ( comp < 0 )
58          {
59              return -1;
60          }
61          else if ( comp > 0 )
62          {
63              return 1;
64          }
65  
66          if ( rn1.getRevision() < rn2.getRevision() )
67          {
68              return -1;
69          }
70          else if ( rn1.getRevision() > rn2.getRevision() )
71          {
72              return 1;
73          }
74  
75          // The name are equal : check the revision
76          if ( rn1.getRevision() < rn2.getRevision() )
77          {
78              return -1;
79          }
80          else if ( rn1.getRevision() > rn2.getRevision() )
81          {
82              return 1;
83          }
84  
85          return 0;
86      }
87  }