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package Torello.Java.Function;

import java.util.function.Function;

/**
 * Function-Pointer
 * <SPAN CLASS=TJF>Input:</SPAN> {@code A, B, C, D}
 * <SPAN CLASS=TJF>Output:</SPAN> {@code R}.
 * 
 * <BR /><BR />
 * <EMBED CLASS='external-html' DATA-FILE-ID=BIG_FUNCTION>
 * <EMBED CLASS="globalDefs" DATA-Name='Quad Function' DATA-Number=four>
 * 
 * @param <A> The type of the first input-parameter.
 * @param <B> The type of the second input-parameter.
 * @param <C> The type of the third input-parameter.
 * @param <D> The type of the last input-parameter.
 * @param <R> The type of the function-output.
 */
@FunctionalInterface
public interface QuadFunction<A, B, C, D, R>
{
    /**
     * Applies {@code 'this'} function to the given arguments.
     * <BR /><BR /><EMBED CLASS='external-html' DATA-FILE-ID=FUNC_INTER_METH>
     *
     * @param a the first input argument
     * @param b the second input argument
     * @param c the third input argument
     * @param d the fourth input argument
     * @return The result of the function.  Return result is of type {@code 'R'}
     */
    public R apply(A a, B b, C c, D d);

    /**
     * <EMBED CLASS='external-html' DATA-FILE-ID=FUNC_THEN_METHOD>
     * @param after <EMBED CLASS='external-html' DATA-FILE-ID=FUNC_THEN_AFTER>
     * @return a composed {@code 'QuadFunction'}, that first applies {@code 'this'} function, and
     * then applies the {@code 'after'} function.
     * @throws NullPointerException This is thrown if {@code 'after'} is null.
     */
    default <V> QuadFunction<A, B, C, D, V> andThen(Function<? super R, ? extends V> after)
    {
        if (after == null)
            throw new NullPointerException("parameter 'after' has been passed null.");

        return (A a, B b, C c, D d) -> after.apply(this.apply(a, b, c, d));
    }
 
}