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 org.apache.directory.server.schema.SerializableComparator;
24
25
26 /**
27 * TupleComparator for index records.
28 *
29 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
30 * @version $Rev: 539571 $
31 */
32 public class ForwardIndexComparator<K> implements TupleComparator<K,Long>
33 {
34 private static final long serialVersionUID = 3257283621751633459L;
35
36 /** The key comparison to use */
37 private final SerializableComparator<K> keyComparator;
38
39
40 /**
41 * Creates an IndexComparator.
42 *
43 * @param keyComparator the table comparator to use for keys
44 */
45 public ForwardIndexComparator( SerializableComparator<K> keyComparator )
46 {
47 this.keyComparator = keyComparator;
48 }
49
50
51 /**
52 * Gets the comparator used to compare keys.
53 *
54 * @return the comparator for comparing keys.
55 */
56 public SerializableComparator<K> getKeyComparator()
57 {
58 return keyComparator;
59 }
60
61
62 /**
63 * Gets the binary comparator used to compare values which are the indices
64 * into the master table.
65 *
66 * @return the binary comparator for comparing values.
67 */
68 public SerializableComparator<Long> getValueComparator()
69 {
70 return LongComparator.INSTANCE;
71 }
72
73
74 /**
75 * Compares key Object to determine their sorting order returning a
76 * value = to, < or > than 0.
77 *
78 * @param key1 the first key to compare
79 * @param key2 the other key to compare to the first
80 * @return 0 if both are equal, a negative value less than 0 if the first
81 * is less than the second, or a postive value if the first is greater than
82 * the second byte array.
83 */
84 public int compareKey( K key1, K key2 )
85 {
86 return getKeyComparator().compare( key1, key2 );
87 }
88
89
90 /**
91 * Comparse value Objects to determine their sorting order returning a
92 * value = to, < or > than 0.
93 *
94 * @param l1 the first Long value to compare
95 * @param l2 the other Long value to compare to the first
96 * @return 0 if both are equal, a negative value less than 0 if the first
97 * is less than the second, or a postive value if the first is greater than
98 * the second Object.
99 */
100 public int compareValue( Long l1, Long l2 )
101 {
102 return ( l1 < l2 ? -1 : ( l1.equals( l2 ) ? 0 : 1 ) );
103 }
104 }