Java List Intersect intersect(List<E>... lists)

Description

Returns a set intersection of the given lists.

License

Open Source License

Parameter

Parameter	Description
lists	The lists to find the set intersection of.
E	The component type of the lists.

Return

The set intersection of the given lists.

Declaration

public static <E> List<E> intersect(List<E>... lists)

Method Source Code


//package com.java2s;
/*//from   w  ww  . j ava 2s.co m
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Lachlan Dowding
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

import java.util.ArrayList;

import java.util.List;

public class Main {
    /**
     * Returns a set intersection of the given lists.
     *
     * @param lists The lists to find the set intersection of.
     * @param <E>   The component type of the lists.
     * @return      The set intersection of the given lists.
     */
    public static <E> List<E> intersect(List<E>... lists) {
        List<E> results = create();

        boolean seeded = false;

        for (List<E> list : lists) {
            if (list != null) {
                if (seeded) {
                    results.retainAll(list);
                } else {
                    results.addAll(list);
                    seeded = true;
                }
            }
        }

        return results;
    }

    /**
     * Creates a new list.
     *
     * @param <E>             The component type of the list.
     * @return                A new list.
     */
    public static <E> List<E> create() {
        return new ArrayList<E>();
    }

    /**
     * Creates a new list with the given initial capacity.
     *
     * @param initialCapacity The initial capacity of the new list.
     * @param <E>             The component type of the list.
     * @return                A new list.
     */
    public static <E> List<E> create(int initialCapacity) {
        return new ArrayList<E>(initialCapacity);
    }
}

Java List Intersect intersect(List... lists)

Description

License

Parameter

Return

Declaration

Method Source Code

Related