package com.zetcode;

import java.util.ArrayList;
import java.util.List;

public class GenericConcatListEx {

    public static void main(String[] args) {

        var vals1 = List.of(1, 2, 3);
        var vals2 = List.of(4, 5, 6);
        var vals3 = List.of(7, 8, 9);

        var vals = concatenate(vals1, vals2, vals3);

        System.out.println(vals);

        var words1 = List.of("pen", "paper", "ink");
        var words2 = List.of("sky", "cloud", "wind");
        var words3 = List.of("tree", "forest", "wood");

        var words = concatenate(words1, words2, words3);

        System.out.println(words);
    }

    @SafeVarargs
    private static <T> List<T> concatenate(List<T>... lists) {
        return new ArrayList<>() {{

            for (List<T> mylist : lists) {

                addAll(mylist);
            }
        }};
    }
}