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From: Ben Stopford <ben@confluent.io>
Date: Fri, 10 Nov 2017 11:12:36 +0000
Message-ID: <CALS7w+tdp4QxJgK19X1LJXtBjMNBQnPD6G7pXKn=JVaS07x3Cg@mail.gmail.com>
Subject: Re: [DISCUSS] KIP-218: Make KafkaFuture.Function java 8 lambda compatible
To: dev@kafka.apache.org
Content-Type: multipart/alternative; boundary="94eb2c06f74023ae3a055d9f008c"
archived-at: Fri, 10 Nov 2017 11:12:59 -0000

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Sounds like a good middle ground to me. What do you think Steven?

On Mon, Nov 6, 2017 at 8:18 PM Colin McCabe <cmccabe@apache.org> wrote:

> It would definitely be nice to use the jdk8 CompletableFuture.  I think
> that's a bit of a separate discussion, though, since it has such heavy
> compatibility implications.
>
> How about making KIP-218 backwards compatible?  As a starting point, you
> can change KafkaFuture#BiConsumer to an interface with no compatibility
> implications, since there are currently no public functions exposed that
> use it.  That leaves KafkaFuture#Function, which is publicly used now.
>
> For the purposes of KIP-218, how about adding a new interface
> FunctionInterface?  Then you can add a function like this:
>
> >  public abstract <R> KafkaFuture<R> thenApply(FunctionInterface<T, R>
> function);
>
> And mark the older declaration as deprecated:
>
> >  @deprecated
> >  public abstract <R> KafkaFuture<R> thenApply(Function<T, R> function);
>
> This is a 100% compatible way to make things nicer for java 8.
>
> cheers,
> Colin
>
>
> On Thu, Nov 2, 2017, at 10:38, Steven Aerts wrote:
> > Hi Tom,
> >
> > Nice observation.
> > I changed "Rejected Alternatives" section to "Other Alternatives", as
> > I see myself as too much of an outsider to the kafka community to be
> > able to decide without this discussion.
> >
> > I see two major factors to decide:
> >  - how soon will KIP-118 (drop support of java 7) be implemented?
> >  - for which reasons do we drop backwards compatibility for public
> > interfaces marked as Evolving
> >
> > If KIP-118 which is scheduled for version 2.0.0 is going to be
> > implemented soon, I agree with you that replacing KafkaFuture with
> > CompletableFuture (or CompletionStage) is a preferable option.
> > But as I am not familiar with the roadmap it is difficult to tell for me.
> >
> >
> > Thanks,
> >
> >
> >    Steven
> >
> >
> > 2017-11-02 11:27 GMT+01:00 Tom Bentley <t.j.bentley@gmail.com>:
> > > Hi Steven,
> > >
> > > I notice you've renamed the template's "Rejected Alternatives" section
> to
> > > "Other Alternatives", suggesting they're not rejected yet (or, if you
> have
> > > rejected them, I think you should give your reasons).
> > >
> > > Personally, I'd like to understand the arguments against simply
> replacing
> > > KafkaFuture with CompletableFuture in Kafka 2.0. In other words, if we
> were
> > > starting without needing to support Java 7 what would be the arguments
> for
> > > having our own KafkaFuture?
> > >
> > > Thanks,
> > >
> > > Tom
> > >
> > > On 1 November 2017 at 16:01, Ted Yu <yuzhihong@gmail.com> wrote:
> > >
> > >> KAFKA-4423 is still open.
> > >> When would Java 7 be dropped ?
> > >>
> > >> Thanks
> > >>
> > >> On Wed, Nov 1, 2017 at 8:56 AM, Ismael Juma <ismael@juma.me.uk>
> wrote:
> > >>
> > >> > On Wed, Nov 1, 2017 at 3:51 PM, Ted Yu <yuzhihong@gmail.com> wrote:
> > >> >
> > >> > > bq. Wait for a kafka release which will not support java 7 anymore
> > >> > >
> > >> > > Do you want to raise a separate thread for the above ?
> > >> > >
> > >> >
> > >> > There is already a KIP for this so a separate thread is not needed.
> > >> >
> > >> > Ismael
> > >> >
> > >>
>

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