@nwangtw thanks for the explanation. I not sure there will be such a use case. The concept of of these types of grouping is really for the spout/bolt APIs. The grouping for a DSL is really coupled with type of the operator. At a DSL level operators like something "keyBy" is really the only operators that are needed. I am also not aware of any other DSLs that allow users to have custom groupings. I think that breaks the DSL abstraction.
I also don't seem any harm with merging this PR. We can still merge it and see in the future. [ Full content available at: https://github.com/apache/incubator-heron/pull/3040 ] This message was relayed via gitbox.apache.org for devnull@infra.apache.org
