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.mavibot.btree.comparator;
021
022
023import java.util.Comparator;
024
025
026/**
027 * Compares integers
028 *
029 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030 */
031public class IntComparator implements Comparator<Integer>
032{
033    /** A static instance of a IntComparator */
034    public static final IntComparator INSTANCE = new IntComparator();
035
036    /**
037     * A private constructor of the IntComparator class
038     */
039    private IntComparator()
040    {
041    }
042
043
044    /**
045     * Compare two integers.
046     *
047     * @param integer1 First integer
048     * @param integer2 Second integer
049     * @return 1 if integer1 > integer2, 0 if integer1 == integer2, -1 if integer1 < integer2
050     */
051    public int compare( Integer integer1, Integer integer2 )
052    {
053        if ( integer1 == integer2 )
054        {
055            return 0;
056        }
057
058        if ( integer1 == null )
059        {
060            if ( integer2 == null )
061            {
062                return 0;
063            }
064            else
065            {
066                return -1;
067            }
068        }
069        else
070        {
071            if ( integer2 == null )
072            {
073                return 1;
074            }
075            else
076            {
077                return integer1.compareTo( integer2 );
078            }
079        }
080    }
081}