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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.comparator;
21  
22  
23  import java.util.Comparator;
24  
25  
26  /**
27   * Compares chars
28   *
29   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
30   */
31  public class CharComparator implements Comparator<Character>
32  {
33      /** A static instance of a CharComparator */
34      public static final CharComparator INSTANCE = new CharComparator();
35  
36      /**
37       * A private constructor of the CharComparator class
38       */
39      private CharComparator()
40      {
41      }
42  
43  
44      /**
45       * Compare two chars.
46       *
47       * @param char1 First char
48       * @param char2 Second char
49       * @return 1 if char1 > char2, 0 if char1 == char2, -1 if char1 < char2
50       */
51      public int compare( Character char1, Character char2 )
52      {
53          if ( char1 == char2 )
54          {
55              return 0;
56          }
57  
58          if ( char1 == null )
59          {
60              if ( char2 == null )
61              {
62                  return 0;
63              }
64              else
65              {
66                  return -1;
67              }
68          }
69          else
70          {
71              if ( char2 == null )
72              {
73                  return 1;
74              }
75              else
76              {
77                  if ( char1 < char2 )
78                  {
79                      return -1;
80                  }
81                  else if ( char1 > char2 )
82                  {
83                      return 1;
84                  }
85                  else
86                  {
87                      return 0;
88                  }
89              }
90          }
91      }
92  }