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1   /*
2    *   Copyright 2004 The Apache Software Foundation
3    *
4    *   Licensed under the Apache License, Version 2.0 (the "License");
5    *   you may not use this file except in compliance with the License.
6    *   You may obtain a copy of the License at
7    *
8    *       http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *   Unless required by applicable law or agreed to in writing, software
11   *   distributed under the License is distributed on an "AS IS" BASIS,
12   *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *   See the License for the specific language governing permissions and
14   *   limitations under the License.
15   *
16   */
17  package org.apache.ldap.server.partition.impl.btree;
18  
19  
20  import java.io.Serializable;
21  
22  import org.apache.ldap.server.schema.SerializableComparator;
23  
24  
25  /***
26   * A TupleComparator that compares keys only.
27   * 
28   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
29   * @version $Rev: 264732 $
30   */
31  public class KeyOnlyComparator
32      implements TupleComparator, Serializable
33  {
34      private static final long serialVersionUID = 3544956549803161397L;
35  
36      private SerializableComparator keyComparator = null;
37  
38  
39      public KeyOnlyComparator( SerializableComparator comparator )
40      {
41          keyComparator = comparator;
42      }
43  
44  
45      /***
46       * Gets the comparator used to compare keys.  May be null in which
47       * case the compareKey method will throw an UnsupportedOperationException.
48       *
49       * @return the comparator for comparing keys.
50       */
51      public SerializableComparator getKeyComparator()
52      {
53          return keyComparator;
54      }
55  
56  
57      /***
58       * Will throw an UnsupportedOperationException every time.
59       */
60      public SerializableComparator getValueComparator()
61      {
62          throw new UnsupportedOperationException();
63      }
64  
65  
66      /***
67       * Compares key Object to determine their sorting order returning a
68       * value = to, < or > than 0.
69       *
70       * @param key1 the first key to compare
71       * @param key2 the other key to compare to the first
72       * @return 0 if both are equal, a negative value less than 0 if the first
73       * is less than the second, or a postive value if the first is greater than
74       * the second byte array.
75       */
76      public int compareKey( Object key1, Object key2 )
77      {
78          return keyComparator.compare( key1, key2 );
79      }
80  
81  
82      /***
83       * Comparse value Objects to determine their sorting order returning a
84       * value = to, < or > than 0.
85       *
86       * @param value1 the first value to compare
87       * @param value2 the other value to compare to the first
88       * @return 0 if both are equal, a negative value less than 0 if the first
89       * is less than the second, or a postive value if the first is greater than
90       * the second Object.
91       */
92      public int compareValue( Object value1, Object value2 )
93      {
94          throw new UnsupportedOperationException();
95      }
96  }