I think we've managed to devolve into unproductive bickering yet once again today or
getting pretty close to it.
No matter how many layers you pass a CompletableFuture through, implementation context
will always make it clear to the end user it is a promise as far as they are concerned.
They would have little reason to call complete(), get() or anything else that is provided
as nice API design convenience in CompletableFuture.
On Mar 8, 2016, at 8:27 AM, Romain Manni-Bucau
<rmannibucau(a)gmail.com> wrote:
2016-03-08 14:22 GMT+01:00 Reza Rahman <reza_rahman(a)lycos.com>:
> I think the JDK team made the right usability call by including everything into
CompletableFuture as a one stop shop. That's why the API will probably prove more
usable in the end.
>
This is also about choosing the right level of exposed API.
> Can a developer erroneously call complete()? Sure, but it's pretty unlikely since
it just doesn't fit the client usage pattern for a promise. And they can make this
unlikely error either for @Asynchronous, CDI asynchronous events and pretty much just
about anywhere CompletableFuture is used as an API.
>
In previous sample I would agree it is a programming error but in a real application you
can pass the future through several layers and then it is less obvious (this async event
opens a nice and fluent way to trigger an event which is actually your returned data as
well: return asyncEvent.fireAsync(myResult);).
> That said, I've also reached out to the JDK team on this. I hope they will have
the time to explain their design motivations themselves and clarify what they would expect
from EE or just about anyone else needing to use their APIs.
>
Thanks
>> On Mar 8, 2016, at 8:06 AM, Romain Manni-Bucau <rmannibucau(a)gmail.com>
wrote:
>>
>> @Reza: can you clarify the behavior of this snippet please:
>>
>> CompletionFuture<AnEvent> cf = asyncEvent.fireAsync(...);
>> cf.complete(new AnEvent()); // not deterministic even if the container will
likely get false calling complete, should it be ignored? throw an exception? other?
>>
>> That's one point where CompletionStage sounds wiser than CompletionFuture for
CDI async events. The javadoc makes the goal clear: "@return a {@link
CompletionStage} allowing further pipeline composition on the asynchronous
operation.". Using CompletionFuture opens the door to the state manipulation which is
not intended (or you have a plan for that?) and which is easily misleading IMHO.
>>
>> CompletionFuture would however make a lot of sense for some parts of EE and to
replace @Asynchronous AsyncResult hack cause there you need to handle the state yourself.
Both being compatible I see it as a consistent usage of each API.
>>
>> Romain Manni-Bucau
>> @rmannibucau | Blog | Github | LinkedIn | Tomitriber
>>
>> 2016-03-08 13:53 GMT+01:00 Reza Rahman <reza_rahman(a)lycos.com>:
>>> FYI - more feedback from just another developer that happens to care a great
deal about EE.
>>>
>>> Begin forwarded message:
>>>
>>>> From: Josh Juneau <juneau001(a)gmail.com>
>>>> Date: March 8, 2016 at 7:41:56 AM EST
>>>> To: "users(a)javaee-spec.java.net"
<users(a)javaee-spec.java.net>
>>>> Subject: [javaee-spec users] Re: CompletableFuture Usage in the Platfom
vs CDI
>>>> Reply-To: users(a)javaee-spec.java.net
>>>>
>>>> Reza-
>>>>
>>>> I am in agreement with you. I agree that CompleteableFuture seems to
make more sense for asynchronous events than CompletionStage. Given that it is widely
acceptable throughout the platform, and the naming aligns more closely with asynchronous
activity...I think CompleteableFuture would be a more consistent and standardized choice.
>>>>
>>>> Thanks
>>>>
>>>> Josh Juneau
>>>> juneau001(a)gmail.com
>>>>
http://jj-blogger.blogspot.com
>>>>
https://www.apress.com/index.php/author/author/view/id/1866
>>>>
>>>>
>>>>> On Mon, Mar 7, 2016 at 6:40 PM, Reza Rahman
<reza_rahman(a)lycos.com> wrote:
>>>>> The CDI EG is incorporating the concept of CompletableFuture into
asynchronous events. Unfortunately for reasons I really don't see as good they are
using it's superinterface CompletionStage instead of CompletableFuture.
>>>>>
>>>>> I think this is a big ease-of-use mistake as CompletableFuture is
designed to be the end user high level gateway API while CompletionStage is mostly as SPI
intended for framework writers.
>>>>>
>>>>> Given that the CompletableFuture concept is pretty widely applicable
throughout the platform I think there is a need for consistency, oversight and guidance
from the platform expert group. Otherwise I fear less than ideal ad-hoc decisions might be
made in this case for CDI and possibly others down the line.
>>>>>
>>>>> What do you think?
>>>>
>>>
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>
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