heronpy/connectors/mock/arraylooper.py

#!/usr/bin/env python
# -*- encoding: utf-8 -*-

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#
#    http://www.apache.org/licenses/LICENSE-2.0
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'''arraylooper.py: module for defining a simple Generator'''

import collections
import itertools
import time

from heronpy.streamlet.generator import Generator

class ArrayLooper(Generator):
  """A ArrayLooper loops the contents of the a user supplied array forever
  """
  def __init__(self, user_iterable, sleep=None):
    super(ArrayLooper, self).__init__()
    if not isinstance(user_iterable, collections.Iterable):
      raise RuntimeError("ArrayLooper must be passed an iterable")
    self._user_iterable = user_iterable
    self._sleep = sleep

  # pylint: disable=unused-argument, attribute-defined-outside-init
  def setup(self, context):
    self._curiter = itertools.cycle(self._user_iterable)

  def get(self):
    if self._sleep is not None:
      time.sleep(self._sleep)
    return next(self._curiter)