sample_app.rb

sample_app.rb

# singleton-as-module loaded once, kept in memory
module App
  module Global extend self    
    def calc
      @calc ||= StatefulCalculator.new 
    end
  end
end
 
App::Global.calc.turn_on # It's possibile to call a method to load data in the statefull java object

class Sample < Sinatra::Base
  get '/' do
     "Welcome, calculator register:#{App::Global.calc.display}"
  end

  get '/add_one' do
    "added one to calculator register, new value:#{App::Global.calc.add(1)}"
  end
end