class Concurrent::ProcessingActor

A new implementation of actor which also simulates the process, therefore it can be used in the same way as Erlang's actors but without occupying thread. A tens of thousands ProcessingActors can run at the same time sharing a thread pool. @example

# Runs on a pool, does not consume 50_000 threads
actors = 50_000.times.map do |i|
  Concurrent::ProcessingActor.act(i) { |a, i| a.receive.then_on(:fast, i) { |m, i| m + i } }
end

actors.each { |a| a.tell 1 }
values = actors.map(&:termination).map(&:value)
values[0,5]                                        # => [1, 2, 3, 4, 5]
values[-5, 5]                                      # => [49996, 49997, 49998, 49999, 50000]

@!macro warn.edge

Public Class Methods

act(*args, &process) click to toggle source

Creates an actor. @see act_listening Behaves the same way, but does not take mailbox as a first argument. @return [ProcessingActor] @example

actor = Concurrent::ProcessingActor.act do |actor|
  actor.receive.then do |message|
    # the actor ends normally with message
    message
  end
end

actor.tell :a_message
    # => <#Concurrent::ProcessingActor:0x7fff11280560 termination:pending>
actor.termination.value! # => :a_message
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 50
def self.act(*args, &process)
  act_listening Promises::Channel.new, *args, &process
end
act_listening(channel, *args, &process) click to toggle source

Creates an actor listening to a specified channel (mailbox). @param [Object] args Arguments passed to the process. @param [Promises::Channel] channel which serves as mailing box. The channel can have limited

size to achieve backpressure.

@yield [actor, *args] to the process to get back a future which represents the actors execution. @yieldparam [ProcessingActor] actor @yieldparam [Object] *args @yieldreturn [Promises::Future(Object)] a future representing next step of execution @return [ProcessingActor]

# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 63
def self.act_listening(channel, *args, &process)
  ProcessingActor.new channel, *args, &process
end
new(channel, *args, &process) click to toggle source
Calls superclass method
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 173
def initialize(channel, *args, &process)
  @Mailbox    = channel
  @Terminated = Promises.future(self, *args, &process).run
  super()
end

Public Instance Methods

ask_op(answer = Promises.resolvable_future, &message_provider) click to toggle source

actor.ask2 { |a| [:count, a] }

# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 153
def ask_op(answer = Promises.resolvable_future, &message_provider)
  # TODO (pitr-ch 12-Dec-2018): is it ok to let the answers be unanswered when the actor terminates
  tell_op(message_provider.call(answer)).then(answer) { |_, a| a }

  # answer.chain { |v| [true, v] } | @Terminated.then
end
inspect()
Alias for: to_s
mailbox() click to toggle source

@return [Promises::Channel] actor's mailbox.

# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 25
def mailbox
  @Mailbox
end
receive(channel = mailbox) click to toggle source

# Receives a message when available, used in the actor's process. # @return [Promises::Future(Object)] a future which will be fulfilled with a message from # mailbox when it is available. def receive(*channels)

channels = [@Mailbox] if channels.empty?
Promises::Channel.select(*channels)
# TODO (pitr-ch 27-Dec-2016): support patterns
#   - put any received message aside if it does not match
#   - on each receive call check the messages put aside
#   - track where the message came from, cannot later receive m form other channel only because it matches

end

# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 79
def receive(channel = mailbox)
  channel.pop_op
end
tell!(message) click to toggle source

Tells a message to the actor. May block current thread if the mailbox is full. {#tell_op} is a better option since it does not block. It's usually used to integrate with threading code. @example

Thread.new(actor) do |actor|
  # ...
  actor.tell! :a_message # blocks until the message is told
  #   (there is a space for it in the channel)
  # ...
end

@param [Object] message @return [self]

# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 95
def tell!(message)
  @Mailbox.push(message)
  self
end
tell_op(message) click to toggle source

Tells a message to the actor. @param [Object] message @return [Promises::Future(ProcessingActor)] a future which will be fulfilled with the actor

when the message is pushed to mailbox.
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 104
def tell_op(message)
  @Mailbox.push_op(message).then(self) { |_ch, actor| actor }
end
termination() click to toggle source

@return [Promises::Future(Object)] a future which is resolved when the actor ends its processing.

It can either be fulfilled with a value when actor ends normally or rejected with
a reason (exception) when actor fails.
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 32
def termination
  @Terminated.with_hidden_resolvable
end
to_ary() click to toggle source
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 167
def to_ary
  [@Mailbox, @Terminated]
end
to_s() click to toggle source

@return [String] string representation.

Calls superclass method
# File lib/concurrent-ruby-edge/concurrent/edge/processing_actor.rb, line 161
def to_s
  format '%s termination: %s>', super[0..-2], termination.state
end
Also aliased as: inspect