Source code for can.listener

    import queue
except ImportError:
    import Queue as queue

[docs]class Listener(object): def on_message_received(self, msg): raise NotImplementedError( "{} has not implemented on_message_received".format( self.__class__.__name__) ) def __call__(self, msg): return self.on_message_received(msg)
[docs] def stop(self): """ Override to cleanup any open resources. """
class RedirectReader(Listener): """ A RedirectReader sends all received messages to another Bus. """ def __init__(self, bus): self.bus = bus def on_message_received(self, msg): self.bus.send(msg)
[docs]class BufferedReader(Listener): """ A BufferedReader is a subclass of :class:`~can.Listener` which implements a **message buffer**: that is, when the :class:`can.BufferedReader` instance is notified of a new message it pushes it into a queue of messages waiting to be serviced. """ def __init__(self): self.buffer = queue.Queue(0) def on_message_received(self, msg): self.buffer.put(msg)
[docs] def get_message(self, timeout=0.5): """ Attempts to retrieve the latest message received by the instance. If no message is available it blocks for given timeout or until a message is received (whichever is shorter), :param float timeout: The number of seconds to wait for a new message. :return: the :class:`~can.Message` if there is one, or None if there is not. """ try: return self.buffer.get(block=True, timeout=timeout) except queue.Empty: return None