1 /**
2 * Copyright 2005-2012 The Kuali Foundation
3 *
4 * Licensed under the Educational Community License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.opensource.org/licenses/ecl2.php
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package org.kuali.rice.krad.comparator;
17
18 import java.io.Serializable;
19 import java.util.Comparator;
20
21 public final class StringValueComparator implements Serializable, Comparator<String> {
22 private static final StringValueComparator INSTANCE = new StringValueComparator();
23
24 private StringValueComparator() {
25 //private
26 }
27
28 public static StringValueComparator getInstance() {
29 return INSTANCE;
30 }
31
32 @Override
33 public int compare(String o1, String o2) {
34 // null guard. non-null value is greater. equal if both are null
35 if (null == o1 || null == o2) {
36 return (null == o1 && null == o2) ? 0 : ((null == o1) ? -1 : 1);
37 }
38
39 return String.CASE_INSENSITIVE_ORDER.compare(o1, o2);
40 }
41 }