Hi All,

I have completed my binary compatibility testing on this as well. Created a
small script & example to make this reproducible:
https://gist.github.com/viktorsomogyi/391defca73e7a46a2c6a40bc699231d4 .

Also, thanks for the votes so far, we're still awaiting for 2 binding.

Cheers,
Viktor

On Thu, Aug 30, 2018 at 5:09 PM Harsha <ka...@harsha.io> wrote:

> +1.
> Thanks,
> Harsha
>
> On Thu, Aug 30, 2018, at 4:19 AM, Attila Sasvári wrote:
> > Thanks for the KIP and the updates Viktor!
> >
> > +1 (non-binding)
> >
> >
> >
> > On Wed, Aug 29, 2018 at 10:44 AM Manikumar <manikumar.re...@gmail.com>
> > wrote:
> >
> > > +1 (non-binding)
> > >
> > > Thanks for the KIP.
> > >
> > > On Wed, Aug 29, 2018 at 1:41 AM Jason Gustafson <ja...@confluent.io>
> > > wrote:
> > >
> > > > +1 Thanks for the updates.
> > > >
> > > > On Tue, Aug 28, 2018 at 1:15 AM, Viktor Somogyi-Vass <
> > > > viktorsomo...@gmail.com> wrote:
> > > >
> > > > > Sure, I've added it. I'll also do the testing today.
> > > > >
> > > > > On Mon, Aug 27, 2018 at 5:03 PM Ismael Juma <ism...@juma.me.uk>
> wrote:
> > > > >
> > > > > > Thanks Viktor. I think it would be good to verify that existing
> > > > > > ExtendedSerializer implementations work without recompiling. This
> > > could
> > > > > be
> > > > > > done as a manual test. If you agree, I suggest adding it to the
> > > testing
> > > > > > plan section.
> > > > > >
> > > > > > Ismael
> > > > > >
> > > > > > On Mon, Aug 27, 2018 at 7:57 AM Viktor Somogyi-Vass <
> > > > > > viktorsomo...@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Thanks guys, I've updated my KIP with this info (so to keep
> > > solution
> > > > > #1).
> > > > > > > If you find it good enough, please vote as well or let me know
> if
> > > you
> > > > > > think
> > > > > > > something is missing.
> > > > > > >
> > > > > > > On Sat, Aug 25, 2018 at 1:14 AM Ismael Juma <ism...@juma.me.uk
> >
> > > > wrote:
> > > > > > >
> > > > > > > > I'm OK with 1 too. It makes me a bit sad that we don't have a
> > > path
> > > > > for
> > > > > > > > removing the method without headers, but it seems like the
> > > simplest
> > > > > and
> > > > > > > > least confusing option (I am assuming that headers are not
> needed
> > > > in
> > > > > > the
> > > > > > > > serializers in the common case).
> > > > > > > >
> > > > > > > > Ismael
> > > > > > > >
> > > > > > > > On Fri, Aug 24, 2018 at 2:42 PM Jason Gustafson <
> > > > ja...@confluent.io>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hey Viktor,
> > > > > > > > >
> > > > > > > > > Good summary. I agree that option 1) seems like the
> simplest
> > > > choice
> > > > > > > and,
> > > > > > > > as
> > > > > > > > > you note, we can always add the default implementation
> later.
> > > > I'll
> > > > > > > leave
> > > > > > > > > Ismael to make a case for the circular forwarding approach
> ;)
> > > > > > > > >
> > > > > > > > > -Jason
> > > > > > > > >
> > > > > > > > > On Fri, Aug 24, 2018 at 3:02 AM, Viktor Somogyi-Vass <
> > > > > > > > > viktorsomo...@gmail.com> wrote:
> > > > > > > > >
> > > > > > > > > > I think in the first draft I didn't provide an
> implementation
> > > > for
> > > > > > > them
> > > > > > > > as
> > > > > > > > > > it seemed very simple and straightforward. I looked up a
> > > couple
> > > > > of
> > > > > > > > > > implementations of the ExtendedSerializers on github and
> the
> > > > > > general
> > > > > > > > > > behavior seems to be that they delegate to the 2 argument
> > > > > > > (headerless)
> > > > > > > > > > method:
> > > > > > > > > >
> > > > > > > > > >
> https://github.com/khoitnm/practice-spring-kafka-grpc/blob/
> > > > > > > > > >
> a6fc9b3395762c4889807baedd822f4653d5dcdd/kafka-common/src/
> > > > > > > > > > main/java/org/tnmk/common/kafka/serialization/protobuf/
> > > > > > > > > > ProtobufSerializer.java
> > > > > > > > > >
> > > > > > >
> > > >
> https://github.com/hong-zhu/nxgen/blob/5cf1427d4e1a8f5c7fab47955af32a
> > > > > > > > > > 0d4f4873af/nxgen-kafka-client/src/main/java/nxgen/kafka/
> > > > > > > > > > client/event/serdes/EventSerializer.java
> > > > > > > > > > https://github.com/jerry-jx/spring-kafka/blob/
> > > > > > > > > >
> ac323ec5b8b9a0ca975db2f7322ff6878fce481a/spring-kafka/src/
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > main/java/org/springframework/kafka/support/serializer/
> > > > > JsonSerializer.java
> > > > > > > > > > https://github.com/enzobonggio/nonblocking-kafka/blob/
> > > > > > > > > >
> bc1a379b2d9593b46cf9604063bc5b38e2785d19/src/main/java/com/
> > > > > > > > > > example/kafka/producer/CustomJsonSerializer.java
> > > > > > > > > >
> > > > > > > > > > Of course 4 example is not representative but it shows
> that
> > > > these
> > > > > > > users
> > > > > > > > > > usually delegate to the "headerless" (2 argument) method.
> > > I've
> > > > > > tried
> > > > > > > to
> > > > > > > > > > look it up on other code search sites but haven't had
> much
> > > luck
> > > > > so
> > > > > > > far.
> > > > > > > > > > Given these examples and the way they implement them I'd
> say
> > > > it's
> > > > > > > more
> > > > > > > > > > common to delegate to the headerless method, that's why I
> > > think
> > > > > > it's
> > > > > > > a
> > > > > > > > > good
> > > > > > > > > > approach for us too. Now having a default implementation
> for
> > > > that
> > > > > > is
> > > > > > > > > again
> > > > > > > > > > a good question. I think current use cases wouldn't
> change in
> > > > > > either
> > > > > > > > case
> > > > > > > > > > (unless we deprecate the headerless one).
> > > > > > > > > > For the new use cases it depends what do we want to
> propagate
> > > > > going
> > > > > > > > > > forward. Do we want only one method to exist or two? As
> > > Ismael
> > > > > > > > > highlighted
> > > > > > > > > > it might be confusing if we have 2 methods, both with
> default
> > > > > > > > > > implementation and in this case we want to push the 3
> > > argument
> > > > > one
> > > > > > > for
> > > > > > > > > > users.
> > > > > > > > > >
> > > > > > > > > > So I see three possible ways:
> > > > > > > > > > 1.) Don't provide a default implementation for the
> headerless
> > > > > > method.
> > > > > > > > > This
> > > > > > > > > > supports the current implementations and encourages the
> > > > > delegation
> > > > > > > > style
> > > > > > > > > in
> > > > > > > > > > future implementations. This might be the simplest
> option.
> > > > > > > > > > 2.) Provide a default implementation for the headerless
> > > method.
> > > > > > This
> > > > > > > > > would
> > > > > > > > > > be a bit confusing, so we'd likely push the use of the 3
> > > > > parameter
> > > > > > > > method
> > > > > > > > > > and deprecate the headerless. This would however further
> > > litter
> > > > > the
> > > > > > > > code
> > > > > > > > > > base with deprecation warnings as we're using the
> headerless
> > > > > method
> > > > > > > in
> > > > > > > > a
> > > > > > > > > > lot of places (think of the current
> > > serializers/deserializers).
> > > > > So
> > > > > > in
> > > > > > > > > this
> > > > > > > > > > case we would want to clean up the code base a little
> where
> > > we
> > > > > can
> > > > > > > and
> > > > > > > > > may
> > > > > > > > > > remove the headerless method entirely in Kafka 3. But
> they
> > > > would
> > > > > > hang
> > > > > > > > > > around until that point. I think in this case the
> > > > implementation
> > > > > > for
> > > > > > > > the
> > > > > > > > > > headerless is a detail question as that is deprecated so
> we
> > > > don't
> > > > > > > > expect
> > > > > > > > > > new implementations to use that method.
> > > > > > > > > > If we decide to move this way, we have explored two
> options
> > > so
> > > > > far:
> > > > > > > > > > returning null / empty array or throwing exceptions.
> (And I
> > > > > > honestly
> > > > > > > > > > started to like the latter as calling that with no real
> > > > > > > implementation
> > > > > > > > is
> > > > > > > > > > really a programming error.)
> > > > > > > > > > 3.) We can do it in multiple steps. In the first step we
> do 1
> > > > and
> > > > > > > later
> > > > > > > > > 2.
> > > > > > > > > > I think it would also make sense as the Kafka code base
> > > heavily
> > > > > > uses
> > > > > > > > the
> > > > > > > > > > headerless method still (think of the existing
> > > > > > > > serializers/deserializers)
> > > > > > > > > > and it would give us time to eliminate/change those use
> > > cases.
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > > Viktor
> > > > > > > > > >
> > > > > > > > > > On Thu, Aug 23, 2018 at 11:55 PM Jason Gustafson <
> > > > > > ja...@confluent.io
> > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > To clarify, what I am suggesting is to only remove the
> > > > default
> > > > > > > > > > > implementation for these methods. So users would be
> > > required
> > > > to
> > > > > > > > > implement
> > > > > > > > > > > serialize(topic, data) and deserialize(topic, data).
> > > > > > > > > > >
> > > > > > > > > > > -Jason
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Aug 23, 2018 at 1:48 PM, Jason Gustafson <
> > > > > > > ja...@confluent.io
> > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hey Viktor,
> > > > > > > > > > > >
> > > > > > > > > > > > Thinking about it a little more, I wonder if we
> should
> > > just
> > > > > not
> > > > > > > > > > provide a
> > > > > > > > > > > > default method for serialize(topic, data) and
> > > > > > deserialize(topic,
> > > > > > > > > data).
> > > > > > > > > > > > Implementing these methods is a trivial burden for
> users
> > > > and
> > > > > it
> > > > > > > > feels
> > > > > > > > > > > like
> > > > > > > > > > > > there's no good solution which allows both methods to
> > > have
> > > > > > > default
> > > > > > > > > > > > implementations.
> > > > > > > > > > > >
> > > > > > > > > > > > Also, ack on KIP-331. Thanks for the pointer.
> > > > > > > > > > > >
> > > > > > > > > > > > -Jason
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, Aug 23, 2018 at 12:30 PM, Viktor
> Somogyi-Vass <
> > > > > > > > > > > > viktorsomo...@gmail.com> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > >> Hi Ismael,
> > > > > > > > > > > >>
> > > > > > > > > > > >> Regarding the deprecation of the 2 parameter method:
> > > > should
> > > > > we
> > > > > > > do
> > > > > > > > > this
> > > > > > > > > > > >> with
> > > > > > > > > > > >> the Serializer interface as well?
> > > > > > > > > > > >>
> > > > > > > > > > > >> I've updated the "Rejected Alternatives" with a few.
> > > > > > > > > > > >> I've added this circular reference one too but
> actually
> > > > > > there's
> > > > > > > a
> > > > > > > > > way
> > > > > > > > > > > >> (pretty heavyweight) by adding a guard class that
> > > prevents
> > > > > > > > recursive
> > > > > > > > > > > >> invocation of either methods. I've tried this out
> but it
> > > > > seems
> > > > > > > to
> > > > > > > > me
> > > > > > > > > > an
> > > > > > > > > > > >> overshoot. So just for the sake of completeness I'll
> > > copy
> > > > it
> > > > > > > here.
> > > > > > > > > :)
> > > > > > > > > > > >>
> > > > > > > > > > > >> public interface Deserializer<T> extends Closeable {
> > > > > > > > > > > >>
> > > > > > > > > > > >>     class Guard {
> > > > > > > > > > > >>
> > > > > > > > > > > >>         private Set<Object> objects =
> > > > > > > > > Collections.synchronizedSet(new
> > > > > > > > > > > >> HashSet<>()); // might as well use concurrent
> hashmap
> > > > > > > > > > > >>
> > > > > > > > > > > >>         private void methodCallInProgress(Object x)
> {
> > > > > > > > > > > >>             objects.add(x);
> > > > > > > > > > > >>         }
> > > > > > > > > > > >>
> > > > > > > > > > > >>         private boolean
> isMethodCallInProgress(Object
> > > x) {
> > > > > > > > > > > >>             return objects.contains(x);
> > > > > > > > > > > >>         }
> > > > > > > > > > > >>
> > > > > > > > > > > >>         private void
> clearMethodCallInProgress(Object
> > > x) {
> > > > > > > > > > > >>             objects.remove(x);
> > > > > > > > > > > >>         }
> > > > > > > > > > > >>
> > > > > > > > > > > >>         private <T> T guard(Supplier<T> supplier) {
> > > > > > > > > > > >>             if (GUARD.isMethodCallInProgress(this))
> {
> > > > > > > > > > > >>                 throw new IllegalStateException("You
> > > must
> > > > > > > > implement
> > > > > > > > > > one
> > > > > > > > > > > of
> > > > > > > > > > > >> the deserialize methods");
> > > > > > > > > > > >>             } else {
> > > > > > > > > > > >>                 try {
> > > > > > > > > > > >>
>  GUARD.methodCallInProgress(this);
> > > > > > > > > > > >>                     return supplier.get();
> > > > > > > > > > > >>                 } finally {
> > > > > > > > > > > >>
> > >  GUARD.clearMethodCallInProgress(this);
> > > > > > > > > > > >>                 }
> > > > > > > > > > > >>             }
> > > > > > > > > > > >>         }
> > > > > > > > > > > >>     }
> > > > > > > > > > > >>
> > > > > > > > > > > >>     Guard GUARD = new Guard();
> > > > > > > > > > > >>
> > > > > > > > > > > >>     void configure(Map<String, ?> configs, boolean
> > > isKey);
> > > > > > > > > > > >>
> > > > > > > > > > > >>     default T deserialize(String topic, byte[]
> data) {
> > > > > > > > > > > >>         return GUARD.guard(() -> deserialize(topic,
> > > null,
> > > > > > > data));
> > > > > > > > > > > >>     }
> > > > > > > > > > > >>
> > > > > > > > > > > >>     default T deserialize(String topic, Headers
> headers,
> > > > > > byte[]
> > > > > > > > > data)
> > > > > > > > > > {
> > > > > > > > > > > >>         return GUARD.guard(() -> deserialize(topic,
> > > > data));
> > > > > > > > > > > >>     }
> > > > > > > > > > > >>
> > > > > > > > > > > >>     @Override
> > > > > > > > > > > >>     void close();
> > > > > > > > > > > >> }
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> Cheers,
> > > > > > > > > > > >> Viktor
> > > > > > > > > > > >>
> > > > > > > > > > > >> On Thu, Aug 23, 2018 at 3:50 PM Ismael Juma <
> > > > > > ism...@juma.me.uk>
> > > > > > > > > > wrote:
> > > > > > > > > > > >>
> > > > > > > > > > > >> > Also, we may consider deprecating the deserialize
> > > method
> > > > > > that
> > > > > > > > does
> > > > > > > > > > not
> > > > > > > > > > > >> take
> > > > > > > > > > > >> > headers. Yes, it's a convenience, but it also adds
> > > > > > confusion.
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > Ismael
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > On Thu, Aug 23, 2018 at 6:48 AM Ismael Juma <
> > > > > > > ism...@juma.me.uk>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > > I think the KIP needs the rejected alternatives
> > > > section
> > > > > to
> > > > > > > > have
> > > > > > > > > > more
> > > > > > > > > > > >> > > detail. For example, another option would be
> > > something
> > > > > > like
> > > > > > > > the
> > > > > > > > > > > >> > following,
> > > > > > > > > > > >> > > which works great as long as one overrides one
> of
> > > the
> > > > > > > methods,
> > > > > > > > > but
> > > > > > > > > > > >> pretty
> > > > > > > > > > > >> > > bad if one doesn't. :)
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > default T deserialize(String topic, byte[]
> data) {
> > > > > > > > > > > >> > >     return deserialize(topic, null, data);
> > > > > > > > > > > >> > > }
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > default T deserialize(String topic, Headers
> headers,
> > > > > > byte[]
> > > > > > > > > data)
> > > > > > > > > > {
> > > > > > > > > > > //
> > > > > > > > > > > >> > > This is the new method
> > > > > > > > > > > >> > >     return deserialize(topic, data);
> > > > > > > > > > > >> > > }
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > On Thu, Aug 23, 2018 at 3:57 AM Viktor
> Somogyi-Vass
> > > <
> > > > > > > > > > > >> > > viktorsomo...@gmail.com> wrote:
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > >> Hi Jason,
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> Thanks for the feedback.
> > > > > > > > > > > >> > >> 1. I chose to return null here because
> according to
> > > > the
> > > > > > > > > > > >> documentation it
> > > > > > > > > > > >> > >> may return null data, therefore the users of
> this
> > > > > methods
> > > > > > > are
> > > > > > > > > > > >> perpared
> > > > > > > > > > > >> > for
> > > > > > > > > > > >> > >> getting a null. Thinking of it though it may be
> > > > better
> > > > > to
> > > > > > > > throw
> > > > > > > > > > an
> > > > > > > > > > > >> > >> exception by default because it'd indicate a
> > > > > programming
> > > > > > > > error.
> > > > > > > > > > > >> However,
> > > > > > > > > > > >> > >> would that be a backward incompatible change?
> I'm
> > > > > simply
> > > > > > > > > thinking
> > > > > > > > > > > of
> > > > > > > > > > > >> > this
> > > > > > > > > > > >> > >> because this is a new behavior that we'd
> introduce
> > > > but
> > > > > > I'm
> > > > > > > > not
> > > > > > > > > > sure
> > > > > > > > > > > >> yet
> > > > > > > > > > > >> > if
> > > > > > > > > > > >> > >> it'd cause problems.
> > > > > > > > > > > >> > >> Do you think it'd make sense to do the same in
> > > > > > `serialize`?
> > > > > > > > > > > >> > >> 2. Yes, I believe that is covered in KIP-331:
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> >
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
> > > > > 331+
> > > > > > > > > > > >>
> > > > Add+default+implementation+to+close%28%29+and+configure%28%
> > > > > > > > > > > >> 29+for+Serializer%2C+Deserializer+and+Serde
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> Cheers,
> > > > > > > > > > > >> > >> Viktor
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> On Wed, Aug 22, 2018 at 6:11 PM Jason
> Gustafson <
> > > > > > > > > > > ja...@confluent.io>
> > > > > > > > > > > >> > >> wrote:
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> > Hey Viktor,
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > This is a nice cleanup. Just a couple quick
> > > > > questions:
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > 1. Rather than returning null for the default
> > > > > > > > > > `deserialize(topic,
> > > > > > > > > > > >> > >> data)`,
> > > > > > > > > > > >> > >> > would it be better to throw
> > > > > > > UnsupportedOperationException?
> > > > > > > > I
> > > > > > > > > > > assume
> > > > > > > > > > > >> > that
> > > > > > > > > > > >> > >> > internally we'll always invoke the api which
> > > takes
> > > > > > > headers.
> > > > > > > > > > > >> Similarly
> > > > > > > > > > > >> > >> for
> > > > > > > > > > > >> > >> > `serialize(topic, data)`.
> > > > > > > > > > > >> > >> > 2. Would it make sense to have default no-op
> > > > > > > > implementations
> > > > > > > > > > for
> > > > > > > > > > > >> > >> > `configure` and `close`?
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > Thanks,
> > > > > > > > > > > >> > >> > Jason
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > On Wed, Aug 22, 2018 at 5:27 AM, Satish
> Duggana <
> > > > > > > > > > > >> > >> satish.dugg...@gmail.com>
> > > > > > > > > > > >> > >> > wrote:
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > > +1
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > On Wed, Aug 22, 2018 at 4:45 PM, Ted Yu <
> > > > > > > > > yuzhih...@gmail.com
> > > > > > > > > > >
> > > > > > > > > > > >> > wrote:
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > > +1
> > > > > > > > > > > >> > >> > > > -------- Original message --------From:
> Kamal
> > > > > > > > > > Chandraprakash
> > > > > > > > > > > <
> > > > > > > > > > > >> > >> > > > kamal.chandraprak...@gmail.com> Date:
> > > 8/22/18
> > > > > > 3:19
> > > > > > > AM
> > > > > > > > > > > >> > (GMT-08:00)
> > > > > > > > > > > >> > >> > To:
> > > > > > > > > > > >> > >> > > > dev@kafka.apache.org Subject: Re: [VOTE]
> > > > > KIP-336:
> > > > > > > > > > > Consolidate
> > > > > > > > > > > >> > >> > > > ExtendedSerializer/Serializer and
> > > > > > > > > > > >> > ExtendedDeserializer/Deserializer
> > > > > > > > > > > >> > >> > > > +1
> > > > > > > > > > > >> > >> > > >
> > > > > > > > > > > >> > >> > > > Thanks for the KIP!
> > > > > > > > > > > >> > >> > > >
> > > > > > > > > > > >> > >> > > > On Wed, Aug 22, 2018 at 2:48 PM Viktor
> > > > > > Somogyi-Vass <
> > > > > > > > > > > >> > >> > > > viktorsomo...@gmail.com>
> > > > > > > > > > > >> > >> > > > wrote:
> > > > > > > > > > > >> > >> > > >
> > > > > > > > > > > >> > >> > > > > Hi All,
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > > > I'd like to start a vote on this KIP (
> > > > > > > > > > > >> > >> > > > >
> > > > > > https://cwiki.apache.org/confluence/pages/viewpage
> > > > > > > .
> > > > > > > > > > > >> > >> > > > action?pageId=87298242)
> > > > > > > > > > > >> > >> > > > > which aims to refactor
> > > > > > > ExtendedSerializer/Serializer
> > > > > > > > > and
> > > > > > > > > > > >> > >> > > > > ExtendedDeserializer/Deserializer.
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > > > To summarize what's the motivation:
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > > > When headers were introduced by KIP-82
> the
> > > > > > > > > > > ExtendedSerializer
> > > > > > > > > > > >> > and
> > > > > > > > > > > >> > >> > > > > ExtendedDeserializer classes were
> created
> > > in
> > > > > > order
> > > > > > > to
> > > > > > > > > > keep
> > > > > > > > > > > >> > >> interface
> > > > > > > > > > > >> > >> > > > > compatibility but still add `T
> > > > > deserialize(String
> > > > > > > > > topic,
> > > > > > > > > > > >> Headers
> > > > > > > > > > > >> > >> > > headers,
> > > > > > > > > > > >> > >> > > > > byte[] data);` and `byte[]
> serialize(String
> > > > > > topic,
> > > > > > > > > > Headers
> > > > > > > > > > > >> > >> headers, T
> > > > > > > > > > > >> > >> > > > > data);` methods that consume the
> headers
> > > for
> > > > > > > > > > > >> > >> > > > serialization/deserialization.
> > > > > > > > > > > >> > >> > > > > The reason for doing so was that Kafka
> at
> > > > that
> > > > > > time
> > > > > > > > > > needed
> > > > > > > > > > > be
> > > > > > > > > > > >> > >> > > compatbile
> > > > > > > > > > > >> > >> > > > > with Java 7. Since we're not compiling
> on
> > > > Java
> > > > > 7
> > > > > > > > > anymore
> > > > > > > > > > > >> > >> (KAFKA-4423)
> > > > > > > > > > > >> > >> > > > we'll
> > > > > > > > > > > >> > >> > > > > try consolidate the way we're using
> these
> > > in
> > > > a
> > > > > > > > backward
> > > > > > > > > > > >> > compatible
> > > > > > > > > > > >> > >> > > > fashion:
> > > > > > > > > > > >> > >> > > > > deprecating the Extended* classes and
> > > moving
> > > > > the
> > > > > > > > > > > >> aforementioned
> > > > > > > > > > > >> > >> > methods
> > > > > > > > > > > >> > >> > > > up
> > > > > > > > > > > >> > >> > > > > in the class hierarchy.
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > > > I'd be happy to get votes or additional
> > > > > feedback
> > > > > > on
> > > > > > > > > this.
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > > > Viktor
> > > > > > > > > > > >> > >> > > > >
> > > > > > > > > > > >> > >> > > >
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> >
> > > > > > > > > > > >>
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
>

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