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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   * Used to compare the sorting order of binary data.
27   * 
28   * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
29   * @version $Rev: 264732 $
30   */
31  public interface TupleComparator extends Serializable
32  {
33      /***
34       * Gets the comparator used to compare keys.  May be null in which
35       * case the compareKey method will throw an UnsupportedOperationException.
36       *
37       * @return the comparator for comparing keys.
38       */
39      SerializableComparator getKeyComparator();
40  
41  
42      /***
43       * Gets the binary comparator used to compare valuess.  May be null in which
44       * case the compareValue method will throw an UnsupportedOperationException.
45       *
46       * @return the binary comparator for comparing values.
47       */
48      SerializableComparator getValueComparator();
49  
50  
51      /***
52       * Compares key Object to determine their sorting order returning a
53       * value = to, < or > than 0.
54       *
55       * @param key1 the first key to compare
56       * @param key2 the other key to compare to the first
57       * @return 0 if both are equal, a negative value less than 0 if the first
58       * is less than the second, or a postive value if the first is greater than
59       * the second byte array.
60       */
61      int compareKey( Object key1, Object key2 );
62  
63  
64      /***
65       * Comparse value Objects to determine their sorting order returning a
66       * value = to, < or > than 0.
67       *
68       * @param value1 the first value to compare
69       * @param value2 the other value to compare to the first
70       * @return 0 if both are equal, a negative value less than 0 if the first
71       * is less than the second, or a postive value if the first is greater than
72       * the second Object.
73       */
74      int compareValue( Object value1, Object value2 );
75  }