# Package org.apache.lucene.search.grouping.function

Support for grouping by `ValueSource`.

See: Description

- Class Summary
  Class | Description
  --- | ---
  FunctionAllGroupHeadsCollector | An implementation of `AllGroupHeadsCollector` for retrieving the most relevant groups when grouping by `ValueSource`.
  FunctionAllGroupsCollector | A collector that collects all groups that match the query.
  FunctionDistinctValuesCollector | Function based implementation of `DistinctValuesCollector`.
  FunctionFirstPassGroupingCollector | Concrete implementation of `FirstPassGroupingCollector` that groups based on `ValueSource` instances.
  FunctionGrouper | Collector factory for grouping by ValueSource
  FunctionSecondPassGroupingCollector | Concrete implementation of `SecondPassGroupingCollector` that groups based on `ValueSource` instances.

## Package org.apache.lucene.search.grouping.function Description

Support for grouping by `ValueSource`.

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