A new build and a new structured concurrency API

[Alex Otenko]

Does this result in the unfinished Futures being Done and Cancelled?

Alex

On Thu, 18 Nov 2021, 10:15 , <forax at univ-mlv.fr> wrote:

>
>
> ------------------------------
>
> *From: *"Alex Otenko" <oleksandr.otenko at gmail.com>
> *To: *"Remi Forax" <forax at univ-mlv.fr>
> *Cc: *"Alan Bateman" <Alan.Bateman at oracle.com>, "loom-dev" <
> loom-dev at openjdk.java.net>
> *Sent: *Jeudi 18 Novembre 2021 10:55:56
> *Subject: *Re: A new build and a new structured concurrency API
>
> What do you mean - no point? I think that requires a proof that there
> really is no point. Which is going to be hard to do because all of the
> interactions are side-effecting, so you are setting up to prove there is
> never any problem from the absence of those side effects.
>
>
> From the javadoc of StructuredExecutor
> "StructuredExecutor defines the shutdown
> <https://download.java.net/java/early_access/loom/docs/api/java.base/java/util/concurrent/StructuredExecutor.html#shutdown()>
> method to shut down an executor without closing it. Shutdown is useful for
> cases where a sub-task completes with a result (or exception) and the
> results of other unfinished tasks are no longer needed."
>
> So by definition, if you are using shudown() or Handler that uses
> shutdown(), it means that you are not interested in the result of the
> computation of the unfinished tasks.
>
>
> Alex
>
>
> Rémi
>
>
> On Thu, 18 Nov 2021, 09:50 Remi Forax, <forax at univ-mlv.fr> wrote:
>
>> ----- Original Message -----
>> > From: "Alex Otenko" <oleksandr.otenko at gmail.com>
>> > To: "Alan Bateman" <Alan.Bateman at oracle.com>
>> > Cc: "loom-dev" <loom-dev at openjdk.java.net>
>> > Sent: Jeudi 18 Novembre 2021 10:36:25
>> > Subject: Re: A new build and a new structured concurrency API
>>
>> > I still fail to see what you win by not invoking onComplete. I see a
>> lot of
>> > problems from indeterminism in other similar contexts.
>>
>> If shutdown has been called, there is no point of trying to complete the
>> parts of the computation that was still running.
>>
>> >
>> > Alex
>>
>> Rémi
>>
>> >
>> > On Thu, 18 Nov 2021, 07:29 Alan Bateman, <Alan.Bateman at oracle.com>
>> wrote:
>> >
>> >> On 17/11/2021 21:48, Alex Otenko wrote:
>> >> > :
>> >> >
>> >> > The docs say onComplete may not be invoked at all. What is being
>> saved
>> >> > here, compared to cancel() that guarantees onComplete will be
>> invoked.
>> >> I see Rémi and Ron have replied pointing out that your question is
>> about
>> >> when the executor is shutdown. Just to add that isn't an anomaly with
>> >> cancel, it's just that the javadoc isn't clear. So if you are using
>> >> Future objects and you invoke a cancel method after the executor is
>> >> shutdown then it's not going to run the onComplete operation.
>> >>
>> >> -Alan
>>
>
>