class Coroutine(object):

  """ Base class of the general coroutine object """

  STATE_RUNNING = 0
  STATE_WAITING = 1
  STATE_CLOSING = 2

  def __init__(self):
    self.state = Coroutine.STATE_WAITING
    self.started = False
    self.args = None
    self.routine = self._co()

  def _co(self):
    self.ret = None
    while True:
      self.args = yield self.ret
      if not self.started:
        self.started = True
        continue
      else:
        self.state = Coroutine.STATE_RUNNING
        self.ret = self.run(self.args)
      if self.state == Coroutine.STATE_CLOSING:
        break
      self.state = Coroutine.STATE_WAITING

  def start(self):
    """ Start the generator """
    if self.routine is None:
      raise RuntimeError('NO task to start running!')
    self.started = True
    self.routine.next()

  def finish(self):
    """ Finish the execution of this routine """
    self.state = Coroutine.STATE_CLOSING
    self.routine.close()

  def run(self, args):
    """ The runing method to be executed every once time"""
    raise NotImplementedError

  def execute(self, arg_obj):
    """ Awake this routine to execute once time """
    return self.routine.send(arg_obj)

class ProducerCoroutine(Coroutine):

  """ The Producer concrete coroutine """

  def __init__(self, cnsmr):
    if not isinstance(cnsmr, Coroutine):
      raise RuntimeError('Consumer is not a Coroutine object')
    self.consumer = cnsmr
    self.consumer.start()
    super(ProducerCoroutine, self).__init__()

  def run(self, args):
    print 'produce ', args
    ret = self.consumer.execute(args)
    print 'consumer return:', ret

  def __call__(self, args):
    """ Custom method for the specific logic """
    self.start()
    while len(args) > 0:
      p = args.pop()
      self.execute(p)
    self.finish()


class ConsumerCoroutine(Coroutine):

  """ The Consumer concrete coroutine """

  def __init__(self):
    super(ConsumerCoroutine, self).__init__()

  def run(self, args):
    print 'consumer get args: ', args
    return 'hahaha' + repr(args)

produce 4
consumer get args: 4
consumer return: hahaha4
produce 3
consumer get args: 3
consumer return: hahaha3
produce 2
consumer get args: 2
consumer return: hahaha2
produce 1
consumer get args: 1
consumer return: hahaha1
produce 0
consumer get args: 0
consumer return: hahaha0