An aggregator just collects all the tuples in a batch. You don’t even have to do anything with them inside the aggregator. When the batch has been fully aggregated, then it emits whatever you tell it to from the complete() method. Sure, the output field name is different, but it’s still the same tuple.
From: Pandian R [mailto:[email protected]] Sent: Thursday, January 29, 2015 4:21 AM To: user; [email protected] Subject: Re: startBatch and finishBatch for Trident functions Thanks. Tried using an Aggregator first, but using aggregator loses the original fields in the tuple and forwards only the new fields to the output stream. On Wed, Jan 28, 2015 at 8:44 PM, Nathan Marz <[email protected]<mailto:[email protected]>> wrote: You should use an Aggregator if you want to process many tuples within a batch, or a State and a StateUpdater if you want to process many tuples across batches. On Wed, Jan 28, 2015 at 9:55 AM, Pandian R <[email protected]<mailto:[email protected]>> wrote: Hi, I am implementing a trident topology and using functions at many steps(as alternative to traditional bolts). But, I don't find a startBatch and finishBatch function. I need to do some operations per batch within a function. Function has prepare and cleanup which is called per tuple. Can someone help how to implement startBatch and finishBatch functions in a Function ? Thanks ! -- Regards, Pandian -- Twitter: @nathanmarz http://nathanmarz.com<http://nathanmarz.com/> -- Regards, Pandian ---------------------------------------------------------------------- This message, and any attachments, is for the intended recipient(s) only, may contain information that is privileged, confidential and/or proprietary and subject to important terms and conditions available at http://www.bankofamerica.com/emaildisclaimer. If you are not the intended recipient, please delete this message.
