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/*-
* ============LICENSE_START=======================================================
* VID
* ================================================================================
* Copyright (C) 2017 AT&T Intellectual Property. All rights reserved.
* Modifications Copyright (C) 2018 Nokia. All rights reserved.
* ================================================================================
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ============LICENSE_END=========================================================
*/
package org.onap.vid.utils;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Set;
public class Intersection {
private Intersection() {
}
/**
* Returns intersection of given lists. Treats those lists as sets, ignores repetitions.
*/
public static <T> List<T> of(Collection<List<T>> lists) {
return lists
.stream()
.map(elements -> (Set<T>) Sets.newHashSet(elements))
.reduce(Sets::intersection)
.map(set -> (List<T>) Lists.newArrayList(set))
.orElse(Collections.emptyList());
}
}
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