001/**
002 * Copyright 2010-2014 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.common.util;
017
018import java.util.HashSet;
019import java.util.Set;
020
021public class SetUtils {
022
023        /**
024         * Return a new <code>Set</code> containing only those elements that appear in both <code>a</code> and <code>b</code>
025         */
026        public static <T> Set<T> intersection(Set<T> a, Set<T> b) {
027                Set<T> result = new HashSet<T>();
028                result.addAll(a);
029                result.retainAll(b);
030                return result;
031        }
032
033        /**
034         * Return a new <code>Set</code> containing all of the elements from both <code>a</code> and <code>b</code>
035         */
036        public static <T> Set<T> union(Set<T> a, Set<T> b) {
037                Set<T> result = new HashSet<T>();
038                result.addAll(a);
039                result.addAll(b);
040                return result;
041        }
042
043        /**
044         * Return a new <code>Set</code> containing only those elements that appear in <code>a</code> but not <code>b</code>
045         */
046        public static <T> Set<T> difference(Set<T> a, Set<T> b) {
047                Set<T> result = new HashSet<T>();
048                result.addAll(a);
049                result.removeAll(b);
050                return result;
051        }
052
053}