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.ldap.model.entry.StringValue; 024import org.apache.directory.api.ldap.model.schema.LdapComparator; 025import org.slf4j.Logger; 026import org.slf4j.LoggerFactory; 027 028 029/** 030 * A comparator for CSN. 031 * 032 * The CSN are ordered depending on an evaluation of its component, in this order : 033 * - time, 034 * - changeCount, 035 * - sid 036 * - modifierNumber 037 * 038 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 039 */ 040public class CsnComparator extends LdapComparator<Object> 041{ 042 /** The serial version UID */ 043 private static final long serialVersionUID = 2L; 044 045 /** A logger for this class */ 046 private static final Logger LOG = LoggerFactory.getLogger( CsnComparator.class ); 047 048 049 /** 050 * The CsnComparator constructor. Its OID is the CsnMatch matching 051 * rule OID. 052 * 053 * @param oid The Comparator's OID 054 */ 055 public CsnComparator( String oid ) 056 { 057 super( oid ); 058 } 059 060 061 /** 062 * {@inheritDoc} 063 */ 064 @Override 065 public int compare( Object csnObj1, Object csnObj2 ) 066 { 067 LOG.debug( "comparing CSN objects '{}' with '{}'", csnObj1, csnObj2 ); 068 069 if ( csnObj1 == csnObj2 ) 070 { 071 return 0; 072 } 073 074 // ------------------------------------------------------------------- 075 // Handle some basis cases 076 // ------------------------------------------------------------------- 077 if ( csnObj1 == null ) 078 { 079 return -1; 080 } 081 082 if ( csnObj2 == null ) 083 { 084 return 1; 085 } 086 087 String csnStr1; 088 String csnStr2; 089 090 if ( csnObj1 instanceof StringValue ) 091 { 092 csnStr1 = ( ( StringValue ) csnObj1 ).getValue(); 093 } 094 else 095 { 096 csnStr1 = csnObj1.toString(); 097 } 098 099 if ( csnObj2 instanceof StringValue ) 100 { 101 csnStr2 = ( ( StringValue ) csnObj2 ).getValue(); 102 } 103 else 104 { 105 csnStr2 = csnObj2.toString(); 106 } 107 108 return csnStr1.compareTo( csnStr2 ); 109 } 110}