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https://issues.apache.org/jira/browse/KAFKA-5684?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16110636#comment-16110636
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Paolo Patierno commented on KAFKA-5684:
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So it seems to me that the serdes parameters aren't related to the processor
node anymore (the {{KStreamPrintProcessor}} in this case) but are related to
the mapper.
Referring on the two above cases from the {{print}} method point of view :
a) the mapper is just provided to the {{PrintForeachAction}} and serdes aren
ignored
b) we have to build a mapper which use the provided serdes (or default ones)
and then passing it to {{PrintForeachAction}}. Today there is a
{{defaultKeyValueMapper}} but it doesn't fit well in this case because it's not
aware of serdes
At same time if serdes parameters are not related to the processor node, the
{{KStreamPrintProcessor}} is really like the {{KStreamPeekProcessor}} with
"forwardDownStream = false".
The only difference is on the {{close}} method which is needed to flush the
{{PrintForeachAction}}.
In any case I think that {{KStreamPrintProcessor}} can be refactored as derived
from {{KStreamPeekProcessor}}.
What do you think [~guozhang] [~james.c] ?
I'm starting to develop a proposal PR for that.
Thanks,
Paolo.
> KStreamPrintProcessor as customized KStreamPeekProcessor
> --------------------------------------------------------
>
> Key: KAFKA-5684
> URL: https://issues.apache.org/jira/browse/KAFKA-5684
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Paolo Patierno
> Assignee: Paolo Patierno
> Priority: Minor
>
> Hi,
> the {{KStreamPrintProcessor}} is implemented from scratch (from the
> {{AbstractProcessor}}) and the same for the related supplier.
> It looks to me that it's just a special {{KStreamPeekProcessor}} with
> forwardDownStream to false and that allows the possibility to specify Serdes
> instances used if key/values are bytes.
> At same time used by a {{print()}} method it provides a fast way to print
> data flowing through the pipeline (while using just {{peek()}} you need to
> write the code).
> I think that it could be useful to refactoring the {{KStreamPrintProcessor}}
> as derived from the {{KStreamPeekProcessor}} customizing its behavior.
> Thanks,
> Paolo.
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