class YourSubscriber
  subscribe(:queue, :or, :something) do |message|
    Dispatcher::Base.dispatch_message(message)
  end
end

class Dispatcher::Base
  
  def can_process_message?
    raise NotImplmenttedError
  end
    
  def process_message
    raise NotImplmentedError
  end
  
  class << self
    def dispatch_message(message)
      valid_dispatchers.each{|d| d.process_message}
    end
    
    private
    
    def valid_dispatchers
      possible_dispatchers.select{|d| d.can_process_message? }
    end
    
    def possible_dispatchers
      descendants.map{|klass| klass.new(message) }
    end
  end
end


class ShipmentEmailDispatcher < Dispatcher::Base
  
  def can_process_message?
    message[:routing_key] == "bulk.shipment.shipped"
  end
  
  def process_message
    Delayed::Job.new(whatever: :idk)
  end
  
end