Java Set Intersect getIntersection(Set s1, Set s2)

Description

Returns the intersection of set s1 and set s2.

License

Open Source License

Parameter

Parameter	Description
s1	a set
s2	another set

Return

the intersection set

Declaration

public static <T> Set<T> getIntersection(Set<T> s1, Set<T> s2) 

Method Source Code

//package com.java2s;
/*/*from w w  w  .j a  v  a  2s.c o  m*/
 *  (c) 2017 Michael A. Beck, Sebastian Henningsen
 *        disco | Distributed Computer Systems Lab
 *        University of Kaiserslautern, Germany
 *  All Rights Reserved.
 *
 * This software is work in progress and is released in the hope that it will
 * be useful to the scientific community. It is provided "as is" without
 * express or implied warranty, including but not limited to the correctness
 * of the code or its suitability for any particular purpose.
 *
 * This software is provided under the MIT License, however, we would 
 * appreciate it if you contacted the respective authors prior to commercial use.
 *
 * If you find our software useful, we would appreciate if you mentioned it
 * in any publication arising from the use of this software or acknowledge
 * our work otherwise. We would also like to hear of any fixes or useful
 */

import java.util.List;
import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;

public class Main {
    /**
     * Returns the intersection of set <code>s1</code> and set <code>s2</code>.
     * @param s1 a set
     * @param s2 another set
     * @return the intersection set
     */
    public static <T> Set<T> getIntersection(Set<T> s1, Set<T> s2) {
        if (s1 == null || s2 == null)
            return new HashSet<T>();

        Set<T> result = new HashSet<T>(s1);
        result.retainAll(s2);
        return result;
    }

    /**
     * Returns the intersection of all sets contained in the list <code>sets</code>.
     * @param sets a list of sets
     * @return the intersection of all sets
     */
    public static <T> Set<T> getIntersection(List<Set<T>> sets) {
        Set<T> result = new HashSet<T>();
        Iterator<Set<T>> iter = sets.iterator();
        if (iter.hasNext()) {
            result.addAll(iter.next());
            for (; iter.hasNext();) {
                result.retainAll(iter.next());
            }
        }
        return result;
    }
}

Related

1. getIntersection(Set a, Set b)
2. intersect(Collection set1, Collection set2)
3. intersect(final Set firstSet, final Set secondSet)
4. intersect(Set one, Set two)
5. intersect(Set set1, Set set2)