How to mimic "vanilla processing" inner classes

Processing inner classes

Regular processing makes much use of java "inner classes" to make PApplet methods and variables to the inner classes (with ruby-processing you can include the Processing::Proxy module to achieve a similar result.

JRubyArt

In JRubyArt Processing::Proxy is a class not a module (and it is designed to allow the use of java reflection methods (pre, draw, post etc) by inheriting classes, so basically it does not do the same thing). However you can use ruby forwardable instead, to produce an even more elegant solution (inmho). See Node class below:-

require 'forwardable'

class Node < Physics::VerletParticle2D
  extend Forwardable
  def_delegators(:@app, :fill, :stroke, :stroke_weight, :ellipse)
  def initialize(pos)
    super(pos)
    @app = $app
  end

  # All we're doing really is adding a display function to a VerletParticle
  def display
    fill(50, 200, 200, 150)
    stroke(50, 200, 200)
    stroke_weight(2)
    ellipse(x, y, 16, 16)
  end
end

To be even more kosher you could replace the global $app via an extra initialize argument.