Removing feature envy

feature_envy.rb

class WebServer
  def start
    Application.new().run
  end
end

class Application
  def run ; end
end

server = WebServer.new
server.start

# What if we want to use the server to run a different application?



class BetterServer
  def initialize(a=Application.new)
    @app = a
  end

  def start
    @app.run
  end
end

class BetterApplication
  def run
    # better, faster
  end
end

app    = BetterApplication.new
server = BetterServer.new(app)
server.start