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 java.io.Serializable;
24
25 import org.apache.directory.api.i18n.I18n;
26 import org.apache.directory.api.ldap.model.schema.LdapComparator;
27 import org.slf4j.Logger;
28 import org.slf4j.LoggerFactory;
29
30
31 /**
32 * A comparator for Strings.
33 *
34 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
35 */
36 public class StringComparator extends LdapComparator<String> implements Serializable
37 {
38 /** The serial version UID */
39 private static final long serialVersionUID = 2L;
40
41 /** A logger for this class */
42 private static final Logger LOG = LoggerFactory.getLogger( StringComparator.class );
43
44
45 /**
46 * The StringComparator constructor. Its OID is the StringMatch matching
47 * rule OID.
48 *
49 * @param oid The Comparator's OID
50 */
51 public StringComparator( String oid )
52 {
53 super( oid );
54 }
55
56
57 /**
58 * {@inheritDoc}
59 */
60 public int compare( String s1, String s2 )
61 {
62 if ( LOG.isDebugEnabled() )
63 {
64 LOG.debug( I18n.msg( I18n.MSG_13749_COMPARING_STRING, s1, s2 ) );
65 }
66
67 if ( s1 == s2 )
68 {
69 return 0;
70 }
71
72 // -------------------------------------------------------------------
73 // Handle some basis cases
74 // -------------------------------------------------------------------
75 if ( s1 == null )
76 {
77 return -1;
78 }
79
80 return s1.compareTo( s2 );
81 }
82 }