mixins java extension

Hi,

I 'd like to add a root-level java extension for mixins (= abstract subclass). So, my syntax will be something like:

mixin MyMixin<SuperClass> {
  int myfield;
  void method1() {
    myfield++'
    SuperClass.method1();
  }
}

Is there any similar example i could look at (most of the examples i have seen about mps' java extensions are about simple non-root constructs like 'unless' or 'ranges')? Would it be helpful to check e.g. baseLanguage's interface implementation?
Any other tip/help would be much appreciated.

Thank you,
George.