org.optaplanner.core.api.score.stream.bi

Interface BiConstraintCollector<A,B,ResultContainer_,Result_>

Type Parameters:

A - the type of the first fact of the tuple in the source BiConstraintStream

B - the type of the second fact of the tuple in the source BiConstraintStream

ResultContainer_ - the mutable accumulation type (often hidden as an implementation detail)

Result_ - the type of the fact of the tuple in the destination ConstraintStream

All Known Implementing Classes:

DefaultBiConstraintCollector

public interface BiConstraintCollector<A,B,ResultContainer_,Result_>

Usually created with ConstraintCollectors. Used by BiConstraintStream#groupBy(BiFunction, BiConstraintCollector), ...

Loosely based on JDK's Collector, but it returns an undo operation for each accumulation to enable incremental score calculation in constraint streams.

See Also:

ConstraintCollectors

Method Summary

Modifier and Type	Method and Description
TriFunction<ResultContainer_,A,B,Runnable>	accumulator() A lambda that extracts data from the matched facts, accumulates it in the result container and returns an undo operation for that accumulation.
Function<ResultContainer_,Result_>	finisher() A lambda that converts the result container into the result.
Supplier<ResultContainer_>	supplier() A lambda that creates the result container, one for each group key combination.

Method Detail

supplier

Supplier<ResultContainer_> supplier()

A lambda that creates the result container, one for each group key combination.

Returns:

never null

accumulator

TriFunction<ResultContainer_,A,B,Runnable> accumulator()

A lambda that extracts data from the matched facts, accumulates it in the result container and returns an undo operation for that accumulation.

Returns:

never null, the undo operation. This lamdba is called when the facts no longer matches.

finisher

Function<ResultContainer_,Result_> finisher()

A lambda that converts the result container into the result.

Returns:

never null