class Pollable
  class << self
    def add_poller(*conditions, &blk)
      pollers << {
        :conditions => conditions,
        :poller =>
          Proc.new do |o|
            o.instance_eval &blk
          end
      }
    end

    def pollers
      @pollers ||= Array.new
    end
  end

  def poll
      self.class.pollers.each do |poller|
          poller[:poller].call(self)
      end
  end
end

class Device < Pollable
  add_poller({:every => 30.seconds, :if => {:icmp_responding => false}}, {:every => 5.minutes, :if => {:icmp_responding => true}}) do
    puts "Poll A #{@id}"
  end

  add_poller(:every => 5.minutes, :subscribe => {:icmp_responding => true}) do
    puts "Poll B #{@id}"
  end

  def initialize
    @id = 5
  end
end