"""This module is responsible to provide means of creating (instantiating) objects
representing Datapoints collections."""
import logging
from typing import Iterable
import attr
from so_magic.utils import Subject
from .datapoints import DatapointsFactory
logger = logging.getLogger(__name__)
# TODO refactor to a composition (not inheritance) implementation of the below class
# reason is that it will be more evident that this class simply combines the
# features of 2 other classes (Subject & DatapointsFactory) to get the job done
[docs]@attr.s
class BroadcastingDatapointsFactory(DatapointsFactory):
"""Creates Datapoints objects and informs its subscribers when that happens.
A factory class that informs its subscribers when a new object that
implements the DatapointsInterface is created (following a request).
Args:
subject (Subject, optional): the subject of observation; the "thing" that others
listen to
"""
subject: Subject = attr.ib(init=True, default=attr.Factory(Subject))
name: str = attr.ib(init=False, default='')
# TODO check if above can be removed, along with self.name = getattr(args[0], 'name', '') in 'create' method
[docs] def create(self, datapoints_factory_type: str, *args, **kwargs) -> Iterable:
"""Create new Datapoints and inform subscribers.
The factory method that returns a new object of DatapointsInterface, by
looking at the registered constructors to delegate the object creation.
Args:
datapoints_factory_type (str): the name of the "constructor" to use
Raises:
RuntimeError: [description]
Returns:
Iterable: instance implementing the DatapointsInterface
"""
self.subject.name = kwargs.pop('id', kwargs.pop('name', kwargs.pop('file_path', '')))
if kwargs:
msg = f"Kwargs: [{', '.join(f'{k}: {v}' for k, v in kwargs.items())}]"
raise RuntimeError("The 'create' method of DatapointsFactory does not support kwargs:", msg)
self.subject.state = super().create(datapoints_factory_type, *args, **kwargs)
# logger.debug(f"Created datapoints: {json.dumps({
# 'datapoints': self.subject.state,
# 'name': self.subject.name,
# })}")
if args and not hasattr(self, '.name'):
self.name = getattr(args[0], 'name', '')
self.subject.notify()
return self.subject.state