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 */
020 package org.apache.directory.shared.ldap.schema.comparators;
021
022
023 import java.util.Comparator;
024
025
026 /**
027 * A comparator for CSN SID.
028 *
029 * The SID is supposed to be an hexadecimal number between 0x0 and 0xfff
030 *
031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032 * @version $Rev$
033 */
034 public class CsnSidComparator implements Comparator<String>
035 {
036 /** A static instance of this comparator */
037 public static final Comparator<String> INSTANCE = new CsnSidComparator();
038
039
040 /**
041 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
042 */
043 public int compare( String sidStr1, String sidStr2 )
044 {
045 // -------------------------------------------------------------------
046 // Handle some basis cases
047 // -------------------------------------------------------------------
048
049 if ( sidStr1 == null )
050 {
051 return ( sidStr2 == null ) ? 0 : -1;
052 }
053
054 if ( sidStr2 == null )
055 {
056 return 1;
057 }
058
059 int sid1 = 0;
060 int sid2 = 0;
061
062 try
063 {
064 sid1 = Integer.parseInt( sidStr1, 16 );
065 }
066 catch ( NumberFormatException nfe )
067 {
068 return -1;
069 }
070
071 try
072 {
073 sid2 = Integer.parseInt( sidStr2, 16 );
074 }
075 catch ( NumberFormatException nfe )
076 {
077 return 1;
078 }
079
080 if ( sid1 > sid2 )
081 {
082 return 1;
083 }
084 else if ( sid2 > sid1 )
085 {
086 return -1;
087 }
088
089 return 0;
090 }
091 }