001package Torello.Java.Function;
002
003import java.util.function.Function;
004
005/**
006 * Function-Pointer
007 * <SPAN CLASS=TJF>Input:</SPAN> {@code A, B, C, D}
008 * <SPAN CLASS=TJF>Output:</SPAN> {@code R}.
009 * 
010 * <BR /><BR />
011 * <EMBED CLASS='external-html' DATA-FILE-ID=BIG_FUNCTION>
012 * <EMBED CLASS="globalDefs" DATA-Name='Quad Function' DATA-Number=four>
013 * 
014 * @param <A> The type of the first input-parameter.
015 * @param <B> The type of the second input-parameter.
016 * @param <C> The type of the third input-parameter.
017 * @param <D> The type of the last input-parameter.
018 * @param <R> The type of the function-output.
019 */
020@FunctionalInterface
021public interface QuadFunction<A, B, C, D, R>
022{
023    /**
024     * Applies {@code 'this'} function to the given arguments.
025     * <BR /><BR /><EMBED CLASS='external-html' DATA-FILE-ID=FUNC_INTER_METH>
026     *
027     * @param a the first input argument
028     * @param b the second input argument
029     * @param c the third input argument
030     * @param d the fourth input argument
031     * @return The result of the function.  Return result is of type {@code 'R'}
032     */
033    public R apply(A a, B b, C c, D d);
034
035    /**
036     * <EMBED CLASS='external-html' DATA-FILE-ID=FUNC_THEN_METHOD>
037     * @param after <EMBED CLASS='external-html' DATA-FILE-ID=FUNC_THEN_AFTER>
038     * @return a composed {@code 'QuadFunction'}, that first applies {@code 'this'} function, and
039     * then applies the {@code 'after'} function.
040     * @throws NullPointerException This is thrown if {@code 'after'} is null.
041     */
042    default <V> QuadFunction<A, B, C, D, V> andThen(Function<? super R, ? extends V> after)
043    {
044        if (after == null)
045            throw new NullPointerException("parameter 'after' has been passed null.");
046
047        return (A a, B b, C c, D d) -> after.apply(this.apply(a, b, c, d));
048    }
049 
050}