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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   * Used to compare the sorting order of binary data.
30   * 
31   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32   * @version $Rev: 610243 $
33   */
34  public interface TupleComparator<K,V> extends Serializable
35  {
36      /**
37       * Gets the comparator used to compare keys.  May be null in which
38       * case the compareKey method will throw an UnsupportedOperationException.
39       *
40       * @return the comparator for comparing keys.
41       */
42      SerializableComparator<K> getKeyComparator();
43  
44  
45      /**
46       * Gets the binary comparator used to compare valuess.  May be null in which
47       * case the compareValue method will throw an UnsupportedOperationException.
48       *
49       * @return the binary comparator for comparing values.
50       */
51      SerializableComparator<V> getValueComparator();
52  
53  
54      /**
55       * Compares key Object to determine their sorting order returning a
56       * value = to, < or > than 0.
57       *
58       * @param key1 the first key to compare
59       * @param key2 the other key to compare to the first
60       * @return 0 if both are equal, a negative value less than 0 if the first
61       * is less than the second, or a postive value if the first is greater than
62       * the second byte array.
63       */
64      int compareKey( K key1, K key2 );
65  
66  
67      /**
68       * Comparse value Objects to determine their sorting order returning a
69       * value = to, < or > than 0.
70       *
71       * @param value1 the first value to compare
72       * @param value2 the other value to compare to the first
73       * @return 0 if both are equal, a negative value less than 0 if the first
74       * is less than the second, or a postive value if the first is greater than
75       * the second Object.
76       */
77      int compareValue( V value1, V value2 );
78  }