def fire( event )
      if @eventSubscribers and @eventSubscribers.include?( event )
         handlers = @eventSubscribers[ event ]
         if handlers
            handlers.each{ |handler| handler.handle( event ) }
         end
      end
   end
def fire( event )
      if @eventSubscribers and @eventSubscribers.include?( event )
         handlers = @eventSubscribers[ event ]
         if handlers
            handlers.each{ |handler| handler.handle( event ) }
         end
      end
   end
Called by client methods to notify event subscribers