[KAFKA-3192] Add implicit unlimited windowed aggregation for KStream

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.10.0.0
• Assignee: Guozhang Wang
• Reporter: Guozhang Wang
• Created: 02/Feb/16 18:40
• Updated: 29/Feb/16 22:04
• Resolved: 29/Feb/16 22:03

Description

Some users would want to have a convenient way to specify "unlimited windowed aggregation" for KStreams. We can add that as a syntax-suger like the following:

KTable aggregateByKey(aggregator)

Where it computes the aggregate WITHOUT windowing, and the underlying implementation just use a RocksDBStore instead of a RocksDBWindowStore, and the returned type will be KTable, not KTable<Windowed, ?>.

With this we can also remove UnlimitedWindows specs.