Side Output

While ParDo always produces a main output PCollection (as the return value from apply), you can also have your ParDo produce any number of additional output PCollections. If you choose to have multiple outputs, your ParDo returns all of the output PCollections (including the main output) bundled together.

Kata: Implement additional output to your ParDo for numbers bigger than 100.


Use MultiOutputReceiver and .withOutputTags to output multiple tagged-outputs in a ParDo.
Refer to the Beam Programming Guide "Additional outputs" section for more information.