The goal of this exercise is to join together the
TaxiFare records for each ride.
For this exercise you will work with two data streams, one with
TaxiRide events generated by a
TaxiRideSource and the other with
TaxiFare events generated by a
TaxiFareSource. See Taxi Data Streams for information on how to download the data and how to work with these stream generators.
(Note that if you want to make your solution truly fault tolerant, you should use the
The result of this exercise is a data stream of
Tuple2<TaxiRide, TaxiFare> records, one for each distinct
rideId. You should ignore the START events, and only join the event for the END of each ride with its corresponding fare data.
The resulting stream should be printed to standard out.
RichCoFlatMapto implement this join operation. Note that you have no control over the order of arrival of the ride END and fare records for each rideId, so you’ll need to be prepared to store either piece of information until the matching info arrives, at which point you can emit a
Tuple2<TaxiRide, TaxiFare>joining the two records together.
Reference solutions are available at GitHub: