Adding another abstract method to Collector interface is also considerably easier from API backward compatibility point of view.
The cost could be either 1) many class with empty implementation of *<S> void collect(OutputTag<S> tag, S value) *method 2) split streamrecord related classes that implement Collector interface from graph generator related classes. For streamrecord ones, we might be able to implement *collect(T out)* by calling *<S> void collect(OutputTag<S> tag, S value). *For graph generator keep it as it is. On Wed, Nov 2, 2016 at 8:14 PM, Chen Qin <c...@uber.com> wrote: > Hi Fabian > > Thanks for your feedback. sorry for late reply. > Some of comments inline. Will update FLIP-13 wiki reflect your comments. > > > - Will multiple side outputs of the same type be supported? > > > It wasn't implemented in prototype. But should be easy to support, we > have unique id in stream record. > > - If I got it right, the FLIP proposes to change the signatures of many > > user-defined functions (FlatMapFunction, WindowFunction, ...). Most of > > these interfaces/classes are annotated with @Public, which means we cannot > > change them in the Flink 1.x release line. What would be alternatives? I > > can think of > a) casting the Collector into a RichCollector (as you do in > > your prototype) or > > This is like a private magic API. Should be 100% compatible but not good > implementation. > > b) retrieve the RichCollector from the RuntimeContext > > > It seems better option, yet many highly used Function like FlatMap will > not get support. To get support, we need to create some redundant classes > inherited from RichFunction( like implement RichFlatMap etc) [we might put > these in different package and isolate impact of this change) > > that a RichFunction provides. > > > I'm not so familiar with the internals of the DataStream API, so I leave > > comments on that to other. > > > Best, Fabian > > On Tue, Oct 25, 2016 at 9:00 AM, Chen Qin <c...@uber.com> wrote: > >> Hey folks, >> >> Please give feedback on FLIP-13! >> https://cwiki.apache.org/confluence/display/FLINK/FLIP-13+ >> Side+Outputs+in+Flink >> JIRA task link to google doc https://issues.apache.org/ >> jira/browse/FLINK-4460 >> >> Thanks, >> Chen Qin >> > > > > -- > -Chen Qin > -- -Chen Qin
