Using constant_missing, to access java enum in jruby

It has been reported that :constant_missing could be useful in accessing java enums, but my experiments make me doubt its value. See prevoius post for a more convential approach. As far as I can tell the redefining of :constant missing is somewhat similar to include Constants module with in this case Axis, RenderMode and Shapes as the available constants you still need to access the actual enums by prefix the enum name Axis::X

Requirements

Requires JRuby, maven

The test employing :constant_missing

# frozen_string_literal: true
require 'java'
require_relative 'test_helper'
require_relative '../lib/pconstants'

module Constants
  include_package 'processing.core.enums'
end

# P3D = Constants::RenderMode::P3D
# X = Constants::Axis::X
# CURVE_VERTEX = Constants::Shapes::CURVE_VERTEX

class Object
  class << self
    alias :const_missing_old :const_missing
    def const_missing c
      Constants.const_get c
    end
  end
end

class SpecTest < Minitest::Test

  def test_constants_is_a_module
    assert_equal Class, Axis.class, 'Constants not recognized as a module'
  end

  def test_p3d
    assert_equal String, RenderMode::P3D.render_mode.class, "failed #{:P3D} is a string"
    assert_equal Java::JavaLang::String, RenderMode::P3D.render_mode.to_java(:string).class, "failed #{:P3D} can be cast as a java string"
    assert_equal 'processing.opengl.PGraphics3D', RenderMode::P3D.render_mode, "failed #{:P3D} lookup"
  end

  def test_numeric
    assert_equal 0, Axis::X.get_axis, "failed #{:X} lookup"
    assert_equal 3, Shapes::CURVE_VERTEX.shape, "failed #{:CURVE_VERTEX} lookup"
  end
end

The Axis enum file

/*
Use of enums is preferred for global access, however the general
recommendation is to include constants in classes that use them.
*/
package processing.core.enums;

public enum Axis {
  X(0),
  Y(1),
  Z(2);

  Axis(int val) {
    this.axis = val;
  }

  public int getAxis(){
    return this.axis;
  }
  private final int axis;
}

The RenderMode enum file

/*
 Use of enums is preferred for global access, however the general
 recommendation is to include constants in classes that use them.
*/
package processing.core.enums;

public enum RenderMode {
   JAVA2D("processing.awt.PGraphicsJava2D"),
   P2D("processing.opengl.PGraphics2D"),
   P3D("processing.opengl.PGraphics3D"),
   FX2D("processing.javafx.PGraphicsFX2D"),
   PDF("processing.pdf.PGraphicsPDF"),
   SVG("processing.svg.PGraphicsSVG"),
   DXF("processing.dxf.RawDXF");

   RenderMode(String val) {
       this.mode = val;
   }

   private final String mode;

   public String renderMode(){
       return this.mode;
   }
}

The Shapes enum file

/*
 Use of enums is preferred for global access, however the general
 recommendation is to include constants in classes that use them.
*/
package processing.core.enums;

public enum Shapes {
   VERTEX(0),
   BEZIER_VERTEX(1),
   QUADRATIC_VERTEX(2),
   CURVE_VERTEX(3),
   BREAK(4);

   Shapes(int val) {
       this.shape = val;
   }

   private final int shape;

   public int getShape() {
       return this.shape;
   }
}