001 /** 002 * Copyright (c) 2000-present Liferay, Inc. All rights reserved. 003 * 004 * This library is free software; you can redistribute it and/or modify it under 005 * the terms of the GNU Lesser General Public License as published by the Free 006 * Software Foundation; either version 2.1 of the License, or (at your option) 007 * any later version. 008 * 009 * This library is distributed in the hope that it will be useful, but WITHOUT 010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 011 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more 012 * details. 013 */ 014 015 package com.liferay.portal.kernel.util; 016 017 import java.util.Comparator; 018 019 /** 020 * @author Shuyang Zhou 021 */ 022 public class NullSafeStringComparator implements Comparator<String> { 023 024 @Override 025 public int compare(String s1, String s2) { 026 if (s1 == null) { 027 if (s2 == null) { 028 return 0; 029 } 030 031 return 1; 032 } 033 034 if (s2 == null) { 035 return -1; 036 } 037 038 return s1.compareTo(s2); 039 } 040 041 }