EDIT

/**

* Copyright (C) 2018 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

import java.util.Comparator;

/**

 * @author k.luther

 * @since 07.12.2018

 */

public class OrderIndexComparator implements Comparator<Integer> {

    private static OrderIndexComparator instance;

    public static OrderIndexComparator instance(){

        if(instance == null){

            instance = new OrderIndexComparator();

        }

        return instance;

    }

    @Override

    public int compare(Integer orderIndex1, Integer orderIndex2) {

       if (orderIndex1 == orderIndex2){

           return 0;

       }

       if (orderIndex1 == null){

           return 1;

       }

       if (orderIndex2 == null){

           return -1;

       }

       if (orderIndex1<orderIndex2){

           return -1;

       }else{

           return 1;

       }

    }