Hi Tony, The reason for this is that the aggregate code is newer. The new code has less layers, compared to the reduce/fold implementation where it is InternalFunction(ReduceApplyFunction(Reduce)) instead of InteralAggregateFunction(Aggregate).
Best, Aljoscha > On 26. Apr 2017, at 06:39, 魏偉哲 <tony19920...@gmail.com> wrote: > > Hi all, > > Recently, I was tracing the source code in streaming api and I was confused > about some implementations. > > When using reduce function with evictor, the *WindowStream* will wrap the > *ReduceFunction* and *ProcessWindowFunction* into > *ReduceApplyProcessWindonwFunction* and put it in > *InternalIterableProcessWindowFunction*. So does fold function. > > However, when using aggregate, the *InternalIterableProcessWindowFunction* > was changed to *InternalAggregateProcessWindowFunction* which was applied > aggregation in the process() method. > > My question is why not implement an *AggregateApplyProcessWindowFunction* > and use *InternalIterableProcessWindowFunction* instead just like reduce, > fold function did. Is there any concern? > > Many thanks, > Tony Wei
