RFR(s): 8140281 add no-arg Optional.orElseThrow() as preferred alternative to get()

[forax at univ-mlv.fr]

----- Mail original -----
> De: "Stuart Marks" <stuart.marks at oracle.com>
> À: "Remi Forax" <forax at univ-mlv.fr>
> Cc: "core-libs-dev" <core-libs-dev at openjdk.java.net>
> Envoyé: Samedi 9 Décembre 2017 01:00:06
> Objet: Re: RFR(s): 8140281 add no-arg Optional.orElseThrow() as preferred alternative to get()

> Please, let's not derail this thread. :-)
> 
> I think would be a good thing to think about, so I've filed a JIRA issue to
> track it:
> 
> https://bugs.openjdk.java.net/browse/JDK-8193279
> 
> s'marks


Thanks,
Rémi

> 
> 
> On 12/8/17 1:45 AM, Remi Forax wrote:
>> Let's gently derail this thread, the is another pain point with the current
>> optional API,
>> it seems that are no simple way to transform an Optional<Integer> to an
>> OptionalInt and vice-versa.
>> 
>> It's painful because we start to see interface that returns by example
>> OptionalInt while the implementation you want to connect with return an
>> Optional<Integer>.
>> 
>> The only workaround seems to be to use a Stream/IntStream:
>>   Optional -> OptionalInt
>>     optional.stream().mapToInt(x -> x).findFirst()
>>   OptionalInt -> Optional
>>     optionalInt.stream().boxed().findFirst();
>> 
>> I think, Optional should have the method mapTo*/flatMapTo* and
>> Optional[Primitive] the method boxed().
>> 
>> regards,
>> Rémi
>> 
>> ----- Mail original -----
>>> De: "Stuart Marks" <stuart.marks at oracle.com>
>>> À: "core-libs-dev" <core-libs-dev at openjdk.java.net>
>>> Envoyé: Vendredi 8 Décembre 2017 01:33:41
>>> Objet: RFR(s): 8140281 add no-arg Optional.orElseThrow() as preferred
>>> alternative to get()
>> 
>>> Hi all,
>>>
>>> Please review this changeset that introduces a new no-arg method orElseThrow()
>>> to Optional, as a preferred alternative to the get() method.
>>>
>>> Corresponding methods are also added to OptionalDouble, Int, and Long.
>>>
>>> The orElseThrow() method is functionally identical to get(). It has some
>>> affinity with the existing orElseThrow(exceptionSupplier) method, being
>>> equivalent to orElseThrow(NoSuchElementException::new).
>>>
>>> The get() method is functionally unchanged. It is NOT being deprecated, although
>>> some wording in the doc has been added to point to orElseThrow() as the
>>> "preferred alternative." This is part of a (slow) migration away from
>>> Optional.get(), which has an obvious, attractive name that is often misused.
>>> These issues have been discussed on this list previously:
>>>
>>>      http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-April/040484.html
>>>
>>> Please note that much of that discussion was about the then-proposed deprecation
>>> of Optional.get(), which is NOT part of this proposal. There are no plans to
>>> deprecate Optional.get() at this time. This proposal ONLY introduces a new
>>> method orElseThrow() that is identical in function to get().
>>>
>>> Bug report:
>>>
>>>      https://bugs.openjdk.java.net/browse/JDK-8140281
>>>
>>> Webrev:
>>>
>>>      http://cr.openjdk.java.net/~smarks/reviews/8140281/webrev.1/
>>>
>>> Thanks,
>>>
> >> s'marks