2 * ============LICENSE_START=======================================================
4 * ================================================================================
5 * Copyright (C) 2017 - 2019 AT&T Intellectual Property. All rights reserved.
6 * Modifications Copyright (C) 2018 Nokia. All rights reserved.
7 * ================================================================================
8 * Licensed under the Apache License, Version 2.0 (the "License");
9 * you may not use this file except in compliance with the License.
10 * You may obtain a copy of the License at
12 * http://www.apache.org/licenses/LICENSE-2.0
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 * ============LICENSE_END=========================================================
22 package org.onap.vid.utils;
24 import com.google.common.collect.Lists;
25 import com.google.common.collect.Sets;
27 import java.util.Collection;
28 import java.util.Collections;
29 import java.util.List;
33 public class Intersection {
34 private Intersection() {
38 * Returns intersection of given lists. Treats those lists as sets, ignores repetitions.
40 public static <T> List<T> of(Collection<List<T>> lists) {
43 .map(elements -> (Set<T>) Sets.newHashSet(elements))
44 .reduce(Sets::intersection)
45 .map(set -> (List<T>) Lists.newArrayList(set))
46 .orElse(Collections.emptyList());