class Concurrent::RubyExecutorService

def initialize(*args, &block)
  super
  @StopEvent    = Event.new
  @StoppedEvent = Event.new
end

def kill
  synchronize do
    break if shutdown?
    stop_event.set
    ns_kill_execution
    stopped_event.set
  end
  true
end

def ns_running?
  !stop_event.set?
end

def ns_shutdown?
  stopped_event.set?
end

def ns_shutdown_execution
  stopped_event.set
end

def ns_shuttingdown?
  !(ns_running? || ns_shutdown?)
end

def post(*args, &task)
  raise ArgumentError.new('no block given') unless block_given?
  deferred_action = synchronize {
    if running?
      ns_execute(*args, &task)
    else
      fallback_action(*args, &task)
    end
  }
  if deferred_action
    deferred_action.call
  else
    true
  end
end

def shutdown
  synchronize do
    break unless running?
    stop_event.set
    ns_shutdown_execution
  end
  true
end

def stop_event
  @StopEvent
end

def stopped_event
  @StoppedEvent
end

def wait_for_termination(timeout = nil)
  stopped_event.wait(timeout)
end