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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 Strings
28   * 
29   * @author <a href="mailto:labs@labs.apache.org">Mavibot labs Project</a>
30   */
31  public class StringComparator implements Comparator<String>
32  {
33      /**
34       * Compare two Strings.
35       * 
36       * @param string1 First String
37       * @param string2 Second String
38       * @return 1 if string1 > String2, 0 if string1 == String2, -1 if string1 < String2
39       */
40      public int compare( String string1, String string2 )
41      {
42          if ( string1 == string2 )
43          {
44              return 0;
45          }
46  
47          if ( string1 == null )
48          {
49              return -1;
50          }
51          else if ( string2 == null )
52          {
53              return 1;
54          }
55  
56          int result = string1.compareTo( string2 );
57  
58          if ( result < 0 )
59          {
60              return -1;
61          }
62          else if ( result > 0 )
63          {
64              return 1;
65          }
66          else
67          {
68              return 0;
69          }
70      }
71  }