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.shared.ldap.model.schema.comparators;
021
022
023import org.apache.directory.shared.ldap.model.schema.LdapComparator;
024import org.slf4j.Logger;
025import org.slf4j.LoggerFactory;
026
027
028/**
029 * A comparator for UUID. We simply use the UUID compareTo method.
030 * 
031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032 */
033public class UUIDComparator extends LdapComparator<String>
034{
035    /** The serial version UID */
036    private static final long serialVersionUID = 2L;
037
038    /** A logger for this class */
039    private static final Logger LOG = LoggerFactory.getLogger( UUIDComparator.class );
040
041    /**
042     * The UUIDComparator constructor. Its OID is the UUIDMatch matching
043     * rule OID.
044     */
045    public UUIDComparator( String oid )
046    {
047        super( oid );
048    }
049
050    
051    /**
052     * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
053     */
054    public int compare( String uuid1, String uuid2 )
055    {
056        LOG.debug( "comparing UUID objects '{}' with '{}'", uuid1, uuid2 );
057
058        // -------------------------------------------------------------------
059        // Handle some basis cases
060        // -------------------------------------------------------------------
061        if ( uuid1 == null )
062        {
063            return ( uuid2 == null ) ? 0 : -1;
064        }
065        
066        if ( uuid2 == null )
067        {
068            return 1;
069        }
070        
071        return uuid1.compareTo( uuid2 );
072    }
073}