Kafka Streams Topology for online predictions

dataByAirportStream.java

dataByAirportStream.join(regressionsByAirPortTable,(k, v) -> k, DataRegression::new)
         	.mapValues(Predictor::predict)
         	.filter((k, v) -> v != null)
         	.peek((k, v) -> System.out.println("Prediction " + v))
         	.to("predictions");