Optional require(s) NonNull

[Brian Goetz]

Take a look at the code today :)

On Oct 29, 2012, at 12:33 PM, Boaz Nahum wrote:

> I can only blame my poor English.
> 
> Lets forget the 'philosophic' first  part of my question.
> 
> the  second part  asks: According to current implementation in b62,
> 'this.present' is false i.f.f   'this.value' is null --> 'this.present' ==
> (this.value != null ). So why we need 'this.present' ?
> 
> If you allow me insist of the first part - Why won't allow me to create  a
> *present* Optional with null value ?
> 
> On Mon, Oct 29, 2012 at 5:15 PM, Brian Goetz <brian.goetz at oracle.com> wrote:
> 
>> This constructor is for creating a *present* Optional.  You use
>> Optional.empty() to create an *empty* optional.
>> 
>> On Oct 29, 2012, at 11:02 AM, Boaz Nahum wrote:
>> 
>>> I thought I understand Optional till I read the implementation:
>>> 
>>> public Optional(T value) {
>>>       this.value = Objects.requireNonNull(value);
>>>       this.present = true;
>>> }
>>> 
>>> Why 'requireNonNull' non null ? If null is singular value why we need
>> this
>>> class ? just for 'orElse..' methods ?
>>> 
>>> If if value can't be null why we need the 'present' field ?
>>> 
>>> My hopes where that I can use Optional to return a null as a legal value.
>>> 
>>> Thanks
>>> Boaz
>>> 
>> 
>> 
>