Sleeping barber problem with Celluloid

barber.rb

# http://en.wikipedia.org/wiki/Sleeping_barber_problem
require 'celluloid'

class Barbershop
  include Celluloid
  include Celluloid::Logger

  def initialize
    @waiting_room = WaitingRoom.new
    @barber = Barber.new(Actor.current)
    Celluloid::Actor[:waiting_room] = @waiting_room
    Celluloid::Actor[:barber] = @barber
  end

  def enter(customer)
    info "#{customer.name} has entered"
    if @waiting_room.full
      info "no more room for #{customer.name}"
    else
      if @barber.asleep
        info "#{customer.name} is waking the barber"
        @barber.wake_up!(customer)
      else
        info "#{customer.name} is waiting for a haircut"
        @waiting_room.push!(customer)
      end
    end
  end

  def next
    @waiting_room.next
  end
end

class WaitingRoom
  include Celluloid
  include Celluloid::Logger

  def initialize
    @customers = []
  end

  def push(customer)
    @customers << customer
  end

  def full
    @customers.size >= 3
  end

  def next
    @customers.pop
  end

  def customers
    @customers
  end
end

class Barber
  include Celluloid
  include Celluloid::Logger

  attr_reader :served_count

  def initialize(barbershop)
    @barbershop = barbershop
    @asleep = true
    @served_count = 0
  end

  def asleep
    !!@asleep
  end

  def wake_up(customer)
    @customer = customer
    @asleep = false

    cut_hair(customer)

    while customer = @barbershop.next
      cut_hair(customer)
    end

    info "nobody left, going back to sleep"
    @asleep = true
  end

  def cut_hair(customer)
    info "cutting #{customer.name}..."
    rand(2).times do
      sleep(1)
    end
    info "#{customer.name} has finished their haircut"
    @served_count += 1
  end
end

class Customer
  attr_reader :name

  def initialize(name)
    @name = name
  end
end

b = Barbershop.new

1.upto(20).each do |i|
  b.enter(Customer.new(i))
  sleep(rand(30) / 10)
end

loop do
  puts "Total cut: #{Celluloid::Actor[:barber].served_count}"
  sleep(1)
end