Hello, Currently trying to write a simple Samza System that reads from a file and puts the contents onto a Samza-compatible stream. Been basing it off the hello-samza WikipediaSystem example so far. The SystemFactory implementation seemed to be pretty straightforward (get path to file from config and return a SystemConsumer that reads the file at that path), although I am not 100% sure of what the purpose of all the SystemConsumer interface methods are.
start() and stop() seem fairly self-explanatory, getting called at the when the System is started and stopped, respectively (please let me know if I am wrong about any of my understandings). register() seems to be similar to start() in that it will be called near the beginning of the System, although giving access to the SystemStreamPartition and a given partition offset, correct? The poll() method seems to be where most of the action takes place, and going by its name, it is called often or at specified intervals? If so, how does this polling work and how is the interval specified? Also, the List of IncomingMessageEnvelopes that get returned from poll(): these are then forwarded on to their specified SystemStreamPartitions (first arg in the IncomingMessageEnvelope constructor)? Anyway, thanks for your time and let me know how far off I am with my understanding of this (as I can't get anything working with my current system implementation). Will be happy to contribute back Javadoc patch reflecting my amended understanding of this interface afterwards. Jonathan
