1 /**
2 * Copyright 2010-2013 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.common.util;
17
18 import java.util.HashSet;
19 import java.util.Set;
20
21 public class SetUtils {
22
23 /**
24 * Return a new <code>Set</code> containing only those elements that appear in both <code>a</code> and <code>b</code>
25 */
26 public static <T> Set<T> intersection(Set<T> a, Set<T> b) {
27 Set<T> result = new HashSet<T>();
28 result.addAll(a);
29 result.retainAll(b);
30 return result;
31 }
32
33 /**
34 * Return a new <code>Set</code> containing all of the elements from both <code>a</code> and <code>b</code>
35 */
36 public static <T> Set<T> union(Set<T> a, Set<T> b) {
37 Set<T> result = new HashSet<T>();
38 result.addAll(a);
39 result.addAll(b);
40 return result;
41 }
42
43 /**
44 * Return a new <code>Set</code> containing only those elements that appear in <code>a</code> but not <code>b</code>
45 */
46 public static <T> Set<T> difference(Set<T> a, Set<T> b) {
47 Set<T> result = new HashSet<T>();
48 result.addAll(a);
49 result.removeAll(b);
50 return result;
51 }
52
53 }