A Ruby observer implementation...the idea is to use that in my Arduino Tank Monitor!

AnObserverTest.rb

require "./Subscriber"
require "./InheritanceSub"
require "./InheritanceSubB"
require"./ObserverRuby"

observer = ObserverRuby.new
sub1 = Subscriber.new
sub2 = Subscriber.new
sub3 = InheritanceSub.new
sub4 = InheritanceSubB.new
observer.add_subscribers sub1,sub2,sub3,sub4
observer.publish "First publish....done!"
puts
puts
observer.remove_subscribers sub1
observer.publish " Second Publish....done!!"

InheritanceSub.rb

class InheritanceSub < Subscriber
  def some_method
		#do some Thing....
	end 
end

InheritanceSubB.rb

class InheritanceSubB < Subscriber
  def receive_notification notification
		super "| SUbB | "+notification
	end 
end

Observer.rb

class ObserverRuby
  $subscriberList=[]
	def subscriberList
		$subscriberList
	end
	def add_subscribers *subscribers
		subscribers.each{|subscriber| 
			if subscriber.respond_to?('receive_notification')
				self.subscriberList<< subscriber
			end
		}
	end
	def remove_subscribers *subscribers
		subscribers.each{|subscriber| 
				self.subscriberList.delete subscriber
		}
	end
	def publish notification
		self.subscriberList.each{|subscriber|
			subscriber.receive_notification notification
		}
	end
end

Subscriber.rb

class Subscriber

  def receive_notification notification
		puts notification
	end

end