RFR 8050819: Please add java.util.Stream.ofNullable(T object)

[Remi Forax]

On 01/27/2015 11:49 PM, Stuart Marks wrote:
>
> On 1/26/15 2:15 PM, Remi Forax wrote:
>>
>> On 01/26/2015 07:42 PM, Alan Bateman wrote:
>>> On 26/01/2015 18:32, Paul Sandoz wrote:
>>>> On Jan 20, 2015, at 7:05 PM, Paul Sandoz <Paul.Sandoz at oracle.com> 
>>>> wrote:
>>>>> Hi,
>>>>>
>>>>> http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8050819-Stream-ofNullable/webrev/ 
>>>>>
>>>>>
>>>>> Stream.ofNullable can make it easier to work fluently when streams 
>>>>> are
>>>>> produced, for example within flatMap.
>>>>>
>>>> So far there have been "null" reviews :-)
>
> I think I saw an empty review fly by. :-)
>
> One quick note on the tests: the test data factory is
>
>     TestData.Factory.ofSupplier("[0, 1)", ...)
>
> which would seem to me to contain a single value zero, but they all 
> use one as the value. Not that it really matters, but I was puzzling 
> over it.
>
>>> This looks okay to me, and the naming consistent with Optional.
>>>
>>> -Alan.
>>
>> I'm not sure this method pull it's own weight,
>> it can be written like this:
>>    Optional.ofNullable(t).stream()
>
> It's certainly possible, but it seems like an unnecessary level of 
> indirection. The need for something like this has come up multiple 
> times, and it seems logical for it to be next to Stream.of() and 
> Stream.empty().
>
>> I'm pretty sure that the JIT will remove the creation of the 
>> intermediary Optional
>> and adding a method in the JDK that considers that null is an 
>> acceptable value
>> is in my opinion the wrong signal to send.
>
> I guess having a method like this makes it easier for people to deal 
> with their possibly-null-producing code in a new streams world. Such 
> null-producing code already exists. I guess you could say that 
> providing this method encourages people to continue producing nulls, 
> but everybody is already doing this today, so....

I prefer to be optimistic and think that at some point in the future,
people will think twice before returning null or storing null in a 
collection.

Anyway, if you have a code that already produce a null value, you can 
wrap it using Optional
as I've suggested or just let the value be streamed and filter it out, 
that's why we have Objects.nonNull() after all.
   Stream.of(t).filter(Objects::nonNull)

>
> s'marks

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