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"""Defines behavior for WHEN clients send requests.

Each client exposes a non-blocking send_request() method that the
ClientRunner invokes either periodically or in response to some event.
"""

import abc
import thread
import time


class ClientRunner:
  """Abstract interface for sending requests from clients."""

  __metaclass__ = abc.ABCMeta

  def __init__(self, client):
    self._client = client

  @abc.abstractmethod
  def start(self):
    raise NotImplementedError()

  @abc.abstractmethod
  def stop(self):
    raise NotImplementedError()


class OpenLoopClientRunner(ClientRunner):

  def __init__(self, client, interval_generator):
    super(OpenLoopClientRunner, self).__init__(client)
    self._is_running = False
    self._interval_generator = interval_generator

  def start(self):
    self._is_running = True
    self._client.start()
    thread.start_new_thread(self._dispatch_requests, ())

  def stop(self):
    self._is_running = False
    self._client.stop()
    self._client = None

  def _dispatch_requests(self):
    while self._is_running:
      self._client.send_request()
      time.sleep(next(self._interval_generator))


class ClosedLoopClientRunner(ClientRunner):

  def __init__(self, client, request_count):
    super(ClosedLoopClientRunner, self).__init__(client)
    self._is_running = False
    self._request_count = request_count
    # Send a new request on each response for closed loop
    self._client.add_response_callback(self._send_request)

  def start(self):
    self._is_running = True
    for _ in xrange(self._request_count):
      self._client.send_request()
    self._client.start()

  def stop(self):
    self._is_running = False
    self._client.stop()
    self._client = None

  def _send_request(self, response_time):
    if self._is_running:
      self._client.send_request()