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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.server.core.partition.impl.btree;
21  
22  
23  import java.io.Serializable;
24  
25  import org.apache.directory.server.schema.SerializableComparator;
26  
27  
28  /**
29   * A TupleComparator that compares keys only.
30   * 
31   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32   * @version $Rev: 610243 $
33   */
34  public class KeyOnlyComparator<K,V> implements TupleComparator<K,V>, Serializable
35  {
36      private static final long serialVersionUID = 3544956549803161397L;
37  
38      private SerializableComparator<K> keyComparator;
39  
40  
41      public KeyOnlyComparator( SerializableComparator<K> comparator )
42      {
43          keyComparator = comparator;
44      }
45  
46  
47      /**
48       * Gets the comparator used to compare keys.  May be null in which
49       * case the compareKey method will throw an UnsupportedOperationException.
50       *
51       * @return the comparator for comparing keys.
52       */
53      public SerializableComparator<K> getKeyComparator()
54      {
55          return keyComparator;
56      }
57  
58  
59      /**
60       * Will throw an UnsupportedOperationException every time.
61       */
62      public SerializableComparator<V> getValueComparator()
63      {
64          throw new UnsupportedOperationException();
65      }
66  
67  
68      /**
69       * Compares key Object to determine their sorting order returning a
70       * value = to, < or > than 0.
71       *
72       * @param key1 the first key to compare
73       * @param key2 the other key to compare to the first
74       * @return 0 if both are equal, a negative value less than 0 if the first
75       * is less than the second, or a postive value if the first is greater than
76       * the second byte array.
77       */
78      public int compareKey( K key1, K key2 )
79      {
80          return keyComparator.compare( key1, key2 );
81      }
82  
83  
84      /**
85       * Comparse value Objects to determine their sorting order returning a
86       * value = to, < or > than 0.
87       *
88       * @param value1 the first value to compare
89       * @param value2 the other value to compare to the first
90       * @return 0 if both are equal, a negative value less than 0 if the first
91       * is less than the second, or a postive value if the first is greater than
92       * the second Object.
93       */
94      public int compareValue( V value1, V value2 )
95      {
96          throw new UnsupportedOperationException();
97      }
98  }