"""
Subscriber
==========
This module dedicates a generic object to generate an observer pattern implementation responsible of subscribing to a publisher
"""
# ============================================================================
# STANDARD IMPORTS
# ============================================================================
from itertools import count
# ============================================================================
# INTERNAL IMPORTS
# ============================================================================
from symupy.abstractions import AbsObserver
# ============================================================================
# CLASS AND DEFINITIONS
# ============================================================================
[docs]class Subscriber(AbsObserver):
"""This general dataquery model implements a general publisher pattern to
broadcast information towards different subscribers. Subscribers are
intented to be objects such as vehicles, front/rear gap coordinators.
This creates an subject that can notify to a specific channel where subscribers are registered or
Example:
Create a DataQuery for 2 type of channels, ``automated`` and ``regular`` vehicles::
>>> channels = ('auto','regular')
>>> query = DataQuery(channels)
"""
def __init__(self, publisher, channel="default"):
self._counter = count(0)
self._call = next(self._counter)
self._publisher = publisher
self._channel = channel
publisher.attach(self, channel)
[docs] def update(self):
self._call = next(self._counter)
def __exit__(self, exc_type, exc_value, traceback):
self._publisher.detach(self, self._channel)
