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 java.util.UUID;
024
025import org.slf4j.Logger;
026import org.slf4j.LoggerFactory;
027
028
029/**
030 * A comparator for UUID. We simply use the UUID compareTo method.
031 * 
032 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
033 */
034public class UuidComparator extends SerializableComparator<String>
035{
036    /** The serial version UID */
037    private static final long serialVersionUID = 2L;
038
039    /** A logger for this class */
040    private static final Logger LOG = LoggerFactory.getLogger( UuidComparator.class );
041    private static final boolean IS_DEBUG = LOG.isDebugEnabled();
042
043    public static UuidComparator INSTANCE = new UuidComparator( "1.3.6.1.1.16.4" );
044
045
046    /**
047     * The UUIDComparator constructor. Its OID is the UUIDMatch matching
048     * rule OID.
049     */
050    public UuidComparator( String oid )
051    {
052        super( oid );
053    }
054
055
056    /**
057     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
058     */
059    public int compare( String uuid1, String uuid2 )
060    {
061        if ( IS_DEBUG )
062        {
063            LOG.debug( "comparing UUID objects '{}' with '{}'", uuid1, uuid2 );
064        }
065
066        // -------------------------------------------------------------------
067        // Handle some basis cases
068        // -------------------------------------------------------------------
069        if ( uuid1 == null )
070        {
071            return ( uuid2 == null ) ? 0 : -1;
072        }
073
074        if ( uuid2 == null )
075        {
076            return 1;
077        }
078
079        return uuid1.compareTo( uuid2 );
080    }
081
082
083    /**
084     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
085     */
086    public int compare( UUID uuid1, UUID uuid2 )
087    {
088        if ( IS_DEBUG )
089        {
090            LOG.debug( "comparing UUID objects '{}' with '{}'", uuid1, uuid2 );
091        }
092
093        // -------------------------------------------------------------------
094        // Handle some basis cases
095        // -------------------------------------------------------------------
096        if ( uuid1 == null )
097        {
098            return ( uuid2 == null ) ? 0 : -1;
099        }
100
101        if ( uuid2 == null )
102        {
103            return 1;
104        }
105
106        return uuid1.compareTo( uuid2 );
107    }
108}