# Uses of Package
org.apache.lucene.search.grouping

- Classes in org.apache.lucene.search.grouping used by org.apache.lucene.search.grouping
  Class | Description
  --- | ---
  AllGroupHeadsCollector | This collector specializes in collecting the most relevant document (group head) for each group that matches the query.
  AllGroupHeadsCollector.GroupHead | Represents a group head.
  CollectedSearchGroup | Expert: representation of a group in `FirstPassGroupingCollector`, tracking the top doc and `FieldComparator` slot.
  DistinctValuesCollector.GroupCount | Returned by `DistinctValuesCollector.getGroups()`, representing the value and set of distinct values for the group.
  DoubleRange | Represents a contiguous range of double values, with an inclusive minimum and exclusive maximum
  DoubleRangeFactory | Groups double values into ranges
  GroupDocs | Represents one group in the results.
  GroupFacetCollector | Base class for computing grouped facets.
  GroupFacetCollector.FacetEntry | Represents a facet entry with a value and a count.
  GroupFacetCollector.GroupedFacetResult | The grouped facet result.
  GroupFacetCollector.SegmentResult | Contains the local grouped segment counts for a particular segment.
  GroupingSearch | Convenience class to perform grouping in a non distributed environment.
  GroupReducer | Concrete implementations of this class define what to collect for individual groups during the second-pass of a grouping search.
  GroupSelector | Defines a group, for use by grouping collectors
  GroupSelector.State | What to do with the current value
  LongRange | Represents a contiguous range of long values, with an inclusive minimum and exclusive maximum
  LongRangeFactory | Groups double values into ranges
  SearchGroup | Represents a group that is found during the first pass search.
  SecondPassGroupingCollector | SecondPassGroupingCollector runs over an already collected set of groups, further applying a `GroupReducer` to each group
  TermGroupFacetCollector | An implementation of `GroupFacetCollector` that computes grouped facets based on the indexed terms from DocValues.
  TopGroups | Represents result returned by a grouping search.
  TopGroups.ScoreMergeMode | How the GroupDocs score (if any) should be merged.