001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * https://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.directory.api.ldap.model.schema.comparators; 021 022 023import java.io.Serializable; 024 025import org.apache.directory.api.i18n.I18n; 026import org.apache.directory.api.ldap.model.schema.LdapComparator; 027import org.slf4j.Logger; 028import org.slf4j.LoggerFactory; 029 030 031/** 032 * A comparator for Strings. 033 * 034 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 035 */ 036public class StringComparator extends LdapComparator<String> implements Serializable 037{ 038 /** The serial version UID */ 039 private static final long serialVersionUID = 2L; 040 041 /** A logger for this class */ 042 private static final Logger LOG = LoggerFactory.getLogger( StringComparator.class ); 043 044 045 /** 046 * The StringComparator constructor. Its OID is the StringMatch matching 047 * rule OID. 048 * 049 * @param oid The Comparator's OID 050 */ 051 public StringComparator( String oid ) 052 { 053 super( oid ); 054 } 055 056 057 /** 058 * {@inheritDoc} 059 */ 060 public int compare( String s1, String s2 ) 061 { 062 if ( LOG.isDebugEnabled() ) 063 { 064 LOG.debug( I18n.msg( I18n.MSG_13749_COMPARING_STRING, s1, s2 ) ); 065 } 066 067 if ( s1 == s2 ) 068 { 069 return 0; 070 } 071 072 // ------------------------------------------------------------------- 073 // Handle some basis cases 074 // ------------------------------------------------------------------- 075 if ( s1 == null ) 076 { 077 return -1; 078 } 079 080 return s1.compareTo( s2 ); 081 } 082}