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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 boolean arrays. A boolean is considered as below the other one if the first boolean
28   * is false when the second one is true.
29   *
30   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
31   */
32  public class BooleanArrayComparator implements Comparator<boolean[]>
33  {
34      /** A static instance of a BooleanArrayComparator */
35      public static final BooleanArrayComparator INSTANCE = new BooleanArrayComparator();
36  
37      /**
38       * A private constructor of the BooleanArrayComparator class
39       */
40      private BooleanArrayComparator()
41      {
42      }
43  
44  
45      /**
46       * Compare two boolean arrays.
47       *
48       * @param booleanArray1 First boolean array
49       * @param booleanArray2 Second boolean array
50       * @return 1 if booleanArray1 > booleanArray2, 0 if booleanArray1 == booleanArray2, -1 if booleanArray1 < booleanArray2
51       */
52      public int compare( boolean[] booleanArray1, boolean[] booleanArray2 )
53      {
54          if ( booleanArray1 == booleanArray2 )
55          {
56              return 0;
57          }
58  
59          if ( booleanArray1 == null )
60          {
61              return -1;
62          }
63  
64          if ( booleanArray2 == null )
65          {
66              return 1;
67          }
68  
69          if ( booleanArray1.length < booleanArray2.length )
70          {
71              return -1;
72          }
73  
74          if ( booleanArray1.length > booleanArray2.length )
75          {
76              return 1;
77          }
78  
79          for ( int pos = 0; pos < booleanArray1.length; pos++ )
80          {
81              int comp = compare( booleanArray1[pos], booleanArray2[pos] );
82  
83              if ( comp != 0 )
84              {
85                  return comp;
86              }
87          }
88  
89          return 0;
90      }
91  
92  
93      private int compare( boolean boolean1, boolean boolean2 )
94      {
95          if ( boolean1 == boolean2 )
96          {
97              return 0;
98          }
99  
100         if ( boolean1 )
101         {
102             return 1;
103         }
104         else
105         {
106             return -1;
107         }
108     }
109 }