Tabulators, reducers, etc (original) (raw)

Brian Goetz brian.goetz at oracle.com
Mon Dec 31 10:08:45 PST 2012

One option might be: use "reduce" for the purely functional forms, use accumulate/accumulateConcurrent for the others:

T reduce(T zero, BinaryOperator reducer); Optional reduce(BinaryOperator reducer); U reduce(U zero, BiFunction<U, T, U> accumulator, BinaryOperator reducer); R accumulate(Accumulator<T, R> reducer); R accumulate(Supplier seedFactory, BiBlock<R, T> accumulator, BiBlock<R, R> reducer); R accumulateConcurrent(ConcurrentAccumulator<T, R> tabulator); This would let us get rid of the Tabulator abstraction (it is identical to MutableReducer; both get renamed to Accumulator). Separately, with a small crowbar, we could simplify ConcurrentAccumulator down to fitting into existing SAMs, and the top-level abstraction could go away.

While the concurrent use case is clearly the odd man out here -- suggesting more work is left to do on this -- the rest of it seems an improvement on what we have now. I would like to move forward with this while we continue to work out the correct set of canned accumulators and the correct way to surface concurrent accumulation.

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