Use change listener rather than direct message factory for lidar.

tracking/lidar_cache.py

@@ -2,7 +2,6 @@ from threading import Thread
 from tracking import algorithms
 import tracking.lidar_tracker_pb2 as tracker_pb
 import zmq
-import messaging.messages as messages
 
 
 class LidarCache():
@@ -25,17 +24,17 @@ class LidarCache():
         self.thread = Thread(target=self.do_scanning, args=[sender])
         self.thread.start()
 
-    def do_scanning(self, sender):
+    def do_scanning(self, listener):
         """Performs scans whilst cache is running, and will pass calculated groups data to the sender.
 
         Parameters
         ----------
-        sender: 
-            Any class given in messaging.message_factory. This acts as a listener.
+        listener: 
+            Any object that includes the onGroupsChanged method. 
 
         """
         # Create the 0MQ socket first. This should not be passed between threads.
-        self._mFactory = sender
+        self._mFactory = listener
 
         # Batch over scans, so we don't need to do our own batching to determine groups
         # TODO: Implement custom batching, as iter_scans can be unreliable
@@ -66,8 +65,7 @@ class LidarCache():
                 pointScan.points.append(tracker_pb.Point(
                     angle=point[1], distance=point[2], group_number=group.number))
 
-        self._mFactory.send_message_topic(
-            "lidar_map", messages.ProtoMessage(message=pointScan.SerializeToString()))
+        self._mFactory.onGroupsChanged(pointScan)
 
     def stop_scanning(self):
         self.run = False