01: /*
02: * Copyright 2007 The Kuali Foundation.
03: *
04: * Licensed under the Educational Community License, Version 1.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.opensource.org/licenses/ecl1.php
09: *
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.core.web.comparator;
17:
18: import java.io.Serializable;
19: import java.util.Comparator;
20:
21: public class StringValueComparator implements Serializable, Comparator {
22: private static final StringValueComparator theInstance = new StringValueComparator();
23:
24: public StringValueComparator() {
25: }
26:
27: public static StringValueComparator getInstance() {
28: return theInstance;
29: }
30:
31: public int compare(Object o1, Object o2) {
32: // null guard. non-null value is greater. equal if both are null
33: if (null == o1 || null == o2) {
34: return (null == o1 && null == o2) ? 0 : ((null == o1) ? -1
35: : 1);
36: }
37:
38: String s1 = (String) o1;
39: String s2 = (String) o2;
40:
41: return String.CASE_INSENSITIVE_ORDER.compare(s1, s2);
42: }
43: }
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