vban-cmd-python/vban_cmd/subject.py

73 lines
2.2 KiB
Python

import logging
logger = logging.getLogger(__name__)
class Subject:
def __init__(self):
"""Adds support for observers and callbacks"""
self._observers = list()
self.logger = logger.getChild(self.__class__.__name__)
@property
def observers(self) -> list:
"""returns the current observers"""
return self._observers
def notify(self, event):
"""run callbacks on update"""
for o in self._observers:
if hasattr(o, "on_update"):
o.on_update(event)
else:
if o.__name__ == f"on_{event}":
o()
def add(self, observer):
"""adds an observer to observers"""
try:
iterator = iter(observer)
for o in iterator:
if o not in self._observers:
self._observers.append(o)
self.logger.info(f"{o} added to event observers")
else:
self.logger.error(f"Failed to add {o} to event observers")
except TypeError:
if observer not in self._observers:
self._observers.append(observer)
self.logger.info(f"{observer} added to event observers")
else:
self.logger.error(f"Failed to add {observer} to event observers")
register = add
def remove(self, observer):
"""removes an observer from observers"""
try:
iterator = iter(observer)
for o in iterator:
try:
self._observers.remove(o)
self.logger.info(f"{o} removed from event observers")
except ValueError:
self.logger.error(f"Failed to remove {o} from event observers")
except TypeError:
try:
self._observers.remove(observer)
self.logger.info(f"{observer} removed from event observers")
except ValueError:
self.logger.error(f"Failed to remove {observer} from event observers")
deregister = remove
def clear(self):
"""clears the observers list"""
self._observers.clear()