Into

[Remi Forax]

On 12/26/2012 04:08 PM, Doug Lea wrote:
> On 12/25/12 18:43, Remi Forax wrote:
>> On 12/25/2012 12:25 AM, Joe Bowbeer wrote:
>>> I was going to say something about into() here but the topic has 
>>> morphed to
>>> sequential()?
>>
>> yes, true.
>>
>> I agree with Brian that into is not as great as it can be but I think 
>> the
>> problem is the interface Destination that into uses.
>
> Maybe we are focusing on different problems, but to me the main
> one is a spec/expectations clash: For user-friendliness, we want
> relevant properties of sources to be preserved in destinations.
> But for generality, we want anything to be put into anything.
> This shows up mainly in orderedness, but you can imagine users
> "expecting" any other property as well (like sortedness wrt a
> comparator). I think this is a no-win situation.

that's why we need two different stream ops,
toList/toSet should conserve the property of the source i.e. create the 
'right' Set or List implementation depending on the source property and 
into that uses the destination property.

The second problem is what is the interface of a stream which is split 
to be computed in parallel in order to be gathered without using an 
intermediary data structure as now. For toList/toSet, because the 
pipeline implementation control the Set/List implementation, so there is 
no need of such interface, for into(), the question is is with interface 
pull it's own weight or not ?

>
> -Doug
>

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