public Callable<Double> getPositionCallable() { if (lastImageNumberStreamIndexer == null) { logger.info("Creating lastImageNumberStreamIndexer"); timeSeriesCollection = new ZebraCaptureInputStreamCollection( zebra.getNumberOfPointsCapturedPV(), zebra.getEnc1AvalPV()); lastImageNumberStreamIndexer = new PositionStreamIndexer<Double>(timeSeriesCollection); } numPosCallableReturned++; return lastImageNumberStreamIndexer.getNamedPositionCallable(zSM.getName(), 1); }