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From "Matthias J. Sax" <mj...@informatik.hu-berlin.de>
Subject Question about DataStream class hierarchy
Date Tue, 28 Jul 2015 19:57:05 GMT

I am a little bit confused about the class hierarchy of DataStream. It
has three subclasses: KeyedDataStream, SingleOutputStreamOperator, and

1) Why is the name "SingleOutputStreamOperator" (why OPERATOR ??)

2) Is it correct, that a SplitDataStream emit multiple logical output
streams, while SingleOutputStreamOperator and KeyedDataStream emit a
single logical output stream?
   => If yes, why is a KeyedDataStream not a subclass of
SingleOutputStreamOperator ?

  a) Why does only SingleOutputStreamOperator has method name()/getName()?
  b) Why does only SingleOutputStreamOperator has method setParallelism()?
  c) Should those methods be members of DataStream instead?


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