HigherOrderFunctionVsBuildYourOwn

import java.util.Date;
import java.util.function.Function;

public class MultiParameterFunction {

    // Bad
    @FunctionalInterface
    public interface TriFunction<T, U, V, R> {
        public R customMethod(T t, U u, V v);
    }

    public static void main(String[] args) {
        String stringParam = "Blah";
        Long longParam = new Long("32.0");
        Date date = new Date();

        // Don't do this:
        TriFunction<String, Long, Date, String> someTriFunction = (stringp, longp, datep) ->
                stringp.concat(longp.toString()).concat(datep.toString());

        someTriFunction.customMethod(stringParam, longParam, date);

        // Do this instead. BTW this is an example of a higher order function also known as
        // as the partially applied function pattern.
        Function<String, Function<Long, Function<Date, String>>> betterFunction =
                stringp -> longp -> datep -> stringp.concat(longp.toString()).concat(datep.toString());

        betterFunction.apply(stringParam).apply(longParam).apply(date);
    }

}