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.util;
021    
022    import java.io.Serializable;
023    import java.util.Comparator;
024    
025    
026    /**
027     * Compares Long keys and values within a table.
028     * 
029     * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030     * @version $Revision: 437007 $
031     */
032    public class LongComparator implements Comparator<Object>, Serializable
033    {
034        /** A instance of this comparator */
035        public static final LongComparator INSTANCE = new LongComparator();
036    
037        /**
038         * Version id for serialization.
039         */
040        static final long serialVersionUID = 1L;
041    
042    
043        /**
044         * Compare two objects.
045         * 
046         * @param obj1 First object
047         * @param obj2 Second object
048         * @return 1 if obj1 > obj2, 0 if obj1 == obj2, -1 if obj1 < obj2
049         */
050        public int compare( Object obj1, Object obj2 )
051        {
052            try
053            {
054                Long long1 = (Long)obj1;
055                Long long2 = (Long)obj2;
056                return long1.compareTo( long2 );
057            }
058            catch ( NullPointerException npe )
059            {
060                if ( obj1 == null )
061                {
062                    throw new IllegalArgumentException( "Argument 'obj1' is null" );
063                }
064                else
065                {
066                    throw new IllegalArgumentException( "Argument 'obj2' is null" );
067                }
068            }
069        }
070    }