Re: [Jython-users] Can we do this in Jython: A return-typed method

[Charlie G. <cha...@gm...>]

On Thu, Nov 13, 2008 at 4:23 PM, Alfonso Reyes <ms...@re...> wrote:
> In this case he return type
> would be Sphere and the method bounce(). How could we resolve this in
> Jython?
>
> class Sphere {
>        int number = 10;
>        double diameter = 3.5;
>        double weight = 146.0;
>        String material = " steel";
> }
>
> class BeachBall {
>        Sphere bounce() {
>          return new Sphere();
>          }
> }
>
> public class MethodTyped {
>  public static void main(String[] args) {
>          BeachBall b = new BeachBall();
>          double anyEq =  b.bounce().weight * b.bounce().diameter +
> b.bounce().material.length();
>          System.out.println(anyEq);
>
>  }
> }

I'm not sure I understand the problem.  Jython does its typing at
runtime, so there's no need for casting anything.  If I make BeachBall
and the fields on Sphere public, I can run the following code in
Jython to do the same thing as your main:

b = BeachBall()
print b.bounce().weight * b.bounce().diameter + len(b.bounce().material)

The only thing I needed to change was to use len to get the length of
the string, since it's exposed as a Python unicode object.

Are you asking how to access package protected fields and methods from
Jython?  That's currently only possible by setting the system property
respectJavaAccessibility to false.  You can get to protected items by
subclassing, but that's about it.

Charlie