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 * http://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 org.apache.directory.api.i18n.I18n; 024import org.apache.directory.api.ldap.model.entry.Value; 025import org.apache.directory.api.ldap.model.schema.LdapComparator; 026import org.slf4j.Logger; 027import org.slf4j.LoggerFactory; 028 029 030/** 031 * A comparator for CSN. 032 * 033 * The CSN are ordered depending on an evaluation of its component, in this order : 034 * - time, 035 * - changeCount, 036 * - sid 037 * - modifierNumber 038 * 039 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 040 */ 041public class CsnComparator extends LdapComparator<Object> 042{ 043 /** The serial version UID */ 044 private static final long serialVersionUID = 2L; 045 046 /** A logger for this class */ 047 private static final Logger LOG = LoggerFactory.getLogger( CsnComparator.class ); 048 049 050 /** 051 * The CsnComparator constructor. Its OID is the CsnMatch matching 052 * rule OID. 053 * 054 * @param oid The Comparator's OID 055 */ 056 public CsnComparator( String oid ) 057 { 058 super( oid ); 059 } 060 061 062 /** 063 * {@inheritDoc} 064 */ 065 @Override 066 public int compare( Object csnObj1, Object csnObj2 ) 067 { 068 if ( LOG.isDebugEnabled() ) 069 { 070 LOG.debug( I18n.msg( I18n.MSG_13745_COMPARING_CSN, csnObj1, csnObj2 ) ); 071 } 072 073 if ( csnObj1 == csnObj2 ) 074 { 075 return 0; 076 } 077 078 // ------------------------------------------------------------------- 079 // Handle some basis cases 080 // ------------------------------------------------------------------- 081 if ( csnObj1 == null ) 082 { 083 return -1; 084 } 085 086 if ( csnObj2 == null ) 087 { 088 return 1; 089 } 090 091 String csnStr1; 092 String csnStr2; 093 094 if ( csnObj1 instanceof Value ) 095 { 096 csnStr1 = ( ( Value ) csnObj1 ).getString(); 097 } 098 else 099 { 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}