kafka-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Patrik Kleindl <pklei...@gmail.com>
Subject Re: [DISCUSS] KIP-451: Make TopologyTestDriver output iterable
Date Thu, 11 Apr 2019 20:14:11 GMT
Hi Matthias

Thanks for the questions.

Regarding the return type:
Iterable offers the option of being used in a foreach loop directly and it
gives you access to the .iterator method, too.
(ref:
https://www.techiedelight.com/differences-between-iterator-and-iterable-in-java/
)

To return a List object would require an additional conversion and I
don't see the immediate benefit.

Regarding the ordering:
outputRecordsByTopic gives back a Queue

private final Map<String, Queue<ProducerRecord<byte[], byte[]>>>
outputRecordsByTopic = new HashMap<>();

which has a LinkedList behind it

outputRecordsByTopic.computeIfAbsent(record.topic(), k -> new
LinkedList<>()).add(record);

So the order is handled by the linked list and should not be modified by my
changes,
not even the .stream.map etc. (ref:
https://stackoverflow.com/questions/30258566/java-stream-map-and-collect-order-of-resulting-container
)


Then again, I am open to change it if people have some strong preference

best regards

Patrik


On Thu, 11 Apr 2019 at 17:45, Matthias J. Sax <matthias@confluent.io> wrote:

> Thanks for the KIP!
>
> Overall, this makes sense and can simplify testing.
>
> What I am wondering is, why you suggest to return an `Iterable`? Maybe
> returning an `Iterator` would make more sense? Or a List? Note that the
> order of emits matters, thus returning a generic `Collection` would not
> seem to be appropriate.
>
> Can you elaborate on the advantages to use `Iterable` compared to the
> other options?
>
>
>
> -Matthias
>
> On 4/11/19 2:09 AM, Patrik Kleindl wrote:
> > Hi everyone,
> >
> > I would like to start the discussion on this small enhancement of
> > the TopologyTestDriver.
> >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-451%3A+Make+TopologyTestDriver+output+iterable
> >
> > Pull request is available at https://github.com/apache/kafka/pull/6556
> >
> > Any feedback is welcome
> >
> > best regards
> >
> > Patrik
> >
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message