baseimage-tutorial-framework/lib/tfw/mixins/callback_mixin.py

# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
# All Rights Reserved. See LICENSE file for details.

from functools import partial

from tfw.decorators import LazyInitialise


class CallbackMixin:
    @LazyInitialise
    def _callbacks(self):
        return []

    def subscribe_callback(self, callback, *args, **kwargs):
        """
        Subscribe a callable to invoke once an event is triggered.
        :param callback: callable to be executed on events
        :param *args: arguments passed to callable
        :param **kwargs: kwargs passed to callable
        """
        fun = partial(callback, *args, **kwargs)
        self._callbacks.append(fun)

    def unsubscribe_callback(self, callback):
        self._callbacks.remove(callback)

    def _execute_callbacks(self, *args, **kwargs):
        for callback in self._callbacks:
            callback(*args, **kwargs)