Class PythonMessageObserver

    • Constructor Detail

      • PythonMessageObserver

        public PythonMessageObserver()
    • Method Detail

      • pythonExtension

        public void pythonExtension​(long pythonObject)
        Part of JCC Python interface to object
      • pythonExtension

        public long pythonExtension()
        Part of JCC Python interface to object
      • pythonDecRef

        public void pythonDecRef()
        Part of JCC Python interface to object
      • messageAvailable

        public void messageAvailable​(String mountPoint,
                                     ParsedMessage message)
        Notify that an encoded message is available.

        Beware that this method will be called from an internal dedicated stream-reading thread. Implementations must take to:

        • not perform long processing there to avoid blocking the stream-reading thread
        • take care of thread-safety when extracting data from the message

        The only filtering that can be specified when adding an observer to a NtripClient is based on message type and mount point. If additional filtering is needed (for example on message content like satellites ids, it must be performed by the observer itself when notified (see example below).

        The recommended way to implement this method is to simply build a domain object from the message fields (for example a gnss propagator) and to store it in the observer class as an instance field using a AtomicReference as follows:

         public class GPSProvider implements PVCoordinatesProvider, RTCMMessageObserver {
        
             private final int                                filteringId;
             private final AtomicReference<GPSPropagator> propagator;
        
             public void messageAvailable(String mountPoint, ParsedMessage message) {
                 MessageXXX msg = (MessageXXX) message;
                 GPSPropagator oldPropagator = propagator.get();
                 if (msg.getSatId() == filteringId) {
                     GPSPropagator newPropagator = new GPSPropagator(msg.get...(),
                                                                     msg.get...(),
                                                                     msg.get...());
                     // only set propagator if no other observer was notified
                     // while we were asleep
                     propagator.compareAndSet(oldPropagator, newPropagator);
                 }
             }
        
             public TimeStampedPVCoordinates getPVCoordinates(AbsoluteDate date, Frame frame) {
                 GPSPropagator lastAvailablePropagator = propagator.get();
                 // use the retrieved propagator to compute position-velocity
             }
        
         }
         
        Specified by:
        messageAvailable in interface MessageObserver
        Parameters:
        mountPoint - mount point from which the message comes
        message - last available message