Protocol Interaction

NOTE: This is an advanced feature which is difficult to use correctly. We would recommend avoiding it.

The asynchronous message protocol Celluloid uses can be used directly to add new behavior to actors.

To send a raw asynchronous message to an actor, use Celluloid::Mailbox#<<:

actor.mailbox << MyMessage.new

Methods can wait on incoming MyMessage objects using the Celluloid#receive method:

class MyActor
  include Celluloid

  def initialize
    async.wait_for_my_messages
  end

  def wait_for_my_messages
    loop do
      message = receive { |msg| msg.is_a? MyMessage }
      puts "Got a MyMessage: #{message.inspect}"
    end
  end
end

The #receive method takes a block, and yields any incoming messages which are received by the current actor to the block, waiting for the block to return true. Calls to #receive sleep until a message is received which makes the block return true, at which point the matching message is returned.

Using the #receive method from outside of the actor is marginally useful. Make sure to setup the #receive before sending the messages, otherwise the messages will be dropped as unhandled.

In the future, customized actor behaviors will be possible.