Tabulators -- a catalog

[Remi Forax]

On 12/28/2012 04:28 PM, Brian Goetz wrote:
> So the thing to do here is return Object[] instead of T[] / D[]. Sad, 
> but not terrible.  Not important enough to have the user pass in a 
> factory.  For want of a Pair...

The other solution is to send a j.u.List with a specific non mutable 
implementation able to store only two elements.

Rémi

>
> On 12/28/2012 9:39 AM, Remi Forax wrote:
>> On 12/28/2012 03:23 AM, Brian Goetz wrote:
>>> Here's a catalog of the currently implemented Tabulators.
>>
>> [...]
>>
>>> 3. Partition.  Partitions a stream according to a predicate.  Results
>>> always are a two-element array of something.  Five forms:
>>>
>>>     // Basic
>>>     <T> Tabulator<T, Collection<T>[]>
>>>     partition(Predicate<T> predicate)
>>>
>>>     // Explicit factory
>>>     <T, C extends Collection<T>> Tabulator<T, C[]>
>>>     partition(Predicate<T> predicate,
>>>               Supplier<C> rowFactory)
>>>
>>>     // Partitioned mutable reduce
>>>     <T, D> Tabulator<T, D[]>
>>>     partition(Predicate<T> predicate,
>>>               MutableReducer<T,D> downstream)
>>>
>>>     // Partitioned functional reduce
>>>     Tabulator<T, T[]>
>>>     partition(Predicate<T> predicate,
>>>               T zero,
>>>               BinaryOperator<T> reducer)
>>>
>>>     // Partitioned functional map-reduce
>>>     Tabulator<T, T[]>
>>>     partition(Predicate<T> predicate,
>>>               T zero,
>>>               Function<T, U> mapper,
>>>               BinaryOperator<T> reducer)
>>
>> You can't create an array of T (C, D) safely, so casting an array of
>> Object to an array of T is maybe acceptable if you control all the
>> access to that array like in collections, but here you export it.
>>
>> Rémi
>>