abstractwriter.py

import logging
from queue import Queue
from threading import Thread, Event

from typing import Union

from abstractscreen import AbstractScreen


class AbstractWriter(Thread):
    def __init__(self):
        # call the thread class
        super(AbstractWriter, self).__init__()
        self.__event = Event()
        self.sendQ = Queue()
        self.setDaemon(True)

    def stop(self):
        self.__event.set()

    def stopped(self) -> bool:
        return self.__event.isSet()

    def run(self):
        try:
            while not self.stopped():
                item = self.sendQ.get()
                self.handleItem(item)
                self.sendQ.task_done()

        except Exception as e:
            logging.error("Error communicating")
            logging.error(e, exc_info=True)

    def handleItem(self, item: Union[str, bytes]):
        """
        Processing item object
        Children define specific procedures
        :param item: Data type defined by respective children -
        must be same as in the output method!
        """
        raise NotImplementedError()

    def output(self, screen: 'AbstractScreen'):
        """
        Output screen to the displaying device. Overriden in children
        :param screen: specific screen
        """
        raise NotImplementedError()