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 * https://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.api.ldap.model.schema.comparators;
21
22
23 import org.apache.directory.api.i18n.I18n;
24 import org.apache.directory.api.ldap.model.entry.Value;
25 import org.apache.directory.api.ldap.model.schema.LdapComparator;
26 import org.slf4j.Logger;
27 import org.slf4j.LoggerFactory;
28
29
30 /**
31 * A comparator for CSN.
32 *
33 * The CSN are ordered depending on an evaluation of its component, in this order :
34 * - time,
35 * - changeCount,
36 * - sid
37 * - modifierNumber
38 *
39 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
40 */
41 public class CsnComparator extends LdapComparator<Object>
42 {
43 /** The serial version UID */
44 private static final long serialVersionUID = 2L;
45
46 /** A logger for this class */
47 private static final Logger LOG = LoggerFactory.getLogger( CsnComparator.class );
48
49
50 /**
51 * The CsnComparator constructor. Its OID is the CsnMatch matching
52 * rule OID.
53 *
54 * @param oid The Comparator's OID
55 */
56 public CsnComparator( String oid )
57 {
58 super( oid );
59 }
60
61
62 /**
63 * {@inheritDoc}
64 */
65 @Override
66 public int compare( Object csnObj1, Object csnObj2 )
67 {
68 if ( LOG.isDebugEnabled() )
69 {
70 LOG.debug( I18n.msg( I18n.MSG_13745_COMPARING_CSN, csnObj1, csnObj2 ) );
71 }
72
73 if ( csnObj1 == csnObj2 )
74 {
75 return 0;
76 }
77
78 // -------------------------------------------------------------------
79 // Handle some basis cases
80 // -------------------------------------------------------------------
81 if ( csnObj1 == null )
82 {
83 return -1;
84 }
85
86 if ( csnObj2 == null )
87 {
88 return 1;
89 }
90
91 String csnStr1;
92 String csnStr2;
93
94 if ( csnObj1 instanceof Value )
95 {
96 csnStr1 = ( ( Value ) csnObj1 ).getString();
97 }
98 else
99 {
100 csnStr1 = csnObj1.toString();
101 }
102
103 if ( csnObj2 instanceof Value )
104 {
105 csnStr2 = ( ( Value ) csnObj2 ).getString();
106 }
107 else
108 {
109 csnStr2 = csnObj2.toString();
110 }
111
112 return csnStr1.compareTo( csnStr2 );
113 }
114 }