Self Registering Class

registry.rb

module Types
  module Registry
    REGISTRATIONS = {}

    def mime_type(string)
      REGISTRATIONS[string] = self
    end

    def self.handle_type(string)
      handler_klass = REGISTRATIONS[string].new
      handler_klass.process
    end
  end

  class XML
    extend Registry
    mime_type "string/xml"

    def process
      puts "Yay"
    end
  end
end