Tabulators -- a catalog

[Sam Pullara]

Remind me against what exactly is the issue with having a Pair class? Returning an Object[] here is pretty awful isn't it?

Sam

On Dec 28, 2012, at 10:28 AM, Brian Goetz <brian.goetz at oracle.com> 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...
> 
> 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
>>