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Track

Track event handling subject of the observer.

TrackEventHandler

Inform all registered track-event observers about a track change.

This is the subject of the classical observer pattern

Source code in nowplaying/track/handler.py 
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class TrackEventHandler:
    """Inform all registered track-event observers about a track change.

    This is the subject of the classical observer pattern
    """

    def __init__(self):
        """Initialize the track event handler."""
        self.__observers = []

    def register_observer(self, observer: TrackObserver):
        """Register an observer to be informed about track changes."""
        logger.info("Registering TrackObserver '%s'", observer.__class__.__name__)
        self.__observers.append(observer)

    def remove_observer(self, observer: TrackObserver):
        """Remove an observer from the list of observers."""
        self.__observers.remove(observer)

    def get_observers(self) -> list:
        """Return register observers to allow inspecting them."""
        return self.__observers

    def track_started(self, track: Track):
        """Inform all registered track-event observers about a track started event."""
        logger.info(
            "Sending track-started event to %s observers: %s",
            len(self.__observers),
            track,
        )

        for observer in self.__observers:
            logger.debug(
                "Sending track-started event to observer %s", observer.__class__
            )

            try:
                observer.track_started(track)
            except Exception as error:
                logger.exception(error)

    def track_finished(self, track: Track):
        """Inform all registered track-event observers about a track finished event."""
        logger.info(
            "Sending track-finished event to %s observers: %s",
            len(self.__observers),
            track,
        )

        for observer in self.__observers:
            logger.debug(
                "Sending track-finished event to observer %s", observer.__class__
            )

            try:
                observer.track_finished(track)
            except Exception as error:
                logger.exception(error)

__init__()

Initialize the track event handler.

Source code in nowplaying/track/handler.py 
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def __init__(self):
    """Initialize the track event handler."""
    self.__observers = []

get_observers()

Return register observers to allow inspecting them.

Source code in nowplaying/track/handler.py 
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def get_observers(self) -> list:
    """Return register observers to allow inspecting them."""
    return self.__observers

register_observer(observer)

Register an observer to be informed about track changes.

Source code in nowplaying/track/handler.py 
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def register_observer(self, observer: TrackObserver):
    """Register an observer to be informed about track changes."""
    logger.info("Registering TrackObserver '%s'", observer.__class__.__name__)
    self.__observers.append(observer)

remove_observer(observer)

Remove an observer from the list of observers.

Source code in nowplaying/track/handler.py 
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def remove_observer(self, observer: TrackObserver):
    """Remove an observer from the list of observers."""
    self.__observers.remove(observer)

track_finished(track)

Inform all registered track-event observers about a track finished event.

Source code in nowplaying/track/handler.py 
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def track_finished(self, track: Track):
    """Inform all registered track-event observers about a track finished event."""
    logger.info(
        "Sending track-finished event to %s observers: %s",
        len(self.__observers),
        track,
    )

    for observer in self.__observers:
        logger.debug(
            "Sending track-finished event to observer %s", observer.__class__
        )

        try:
            observer.track_finished(track)
        except Exception as error:
            logger.exception(error)

track_started(track)

Inform all registered track-event observers about a track started event.

Source code in nowplaying/track/handler.py 
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def track_started(self, track: Track):
    """Inform all registered track-event observers about a track started event."""
    logger.info(
        "Sending track-started event to %s observers: %s",
        len(self.__observers),
        track,
    )

    for observer in self.__observers:
        logger.debug(
            "Sending track-started event to observer %s", observer.__class__
        )

        try:
            observer.track_started(track)
        except Exception as error:
            logger.exception(error)