# 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.