org.apache.lucene.search.grouping

## Class TopGroupsCollector<T>

- java.lang.Object
- - org.apache.lucene.search.SimpleCollector
  - - org.apache.lucene.search.grouping.SecondPassGroupingCollector<T>
    - - org.apache.lucene.search.grouping.TopGroupsCollector<T>

- Type Parameters:
    `T` - the type of the group value
  All Implemented Interfaces:
    Collector, LeafCollector

      public class TopGroupsCollector<T>
      extends SecondPassGroupingCollector<T>

  A second-pass collector that collects the TopDocs for each group, and returns them as a `TopGroups` object

- - ### Field Summary

    - ### Fields inherited from class org.apache.lucene.search.grouping.SecondPassGroupingCollector

      `groupReducer, groups, groupSelector, totalGroupedHitCount, totalHitCount`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `TopGroupsCollector(GroupSelector<T> groupSelector, Collection<SearchGroup<T>> groups, Sort groupSort, Sort withinGroupSort, int maxDocsPerGroup, boolean getMaxScores)` Create a new TopGroupsCollector

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `TopGroups<T>` | `getTopGroups(int withinGroupOffset)` Get the TopGroups recorded by this collector

    - ### Methods inherited from class org.apache.lucene.search.grouping.SecondPassGroupingCollector

      `collect, doSetNextReader, getGroupSelector, scoreMode, setScorer`

    - ### Methods inherited from class org.apache.lucene.search.SimpleCollector

      `getLeafCollector`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### TopGroupsCollector

          public TopGroupsCollector(GroupSelector<T> groupSelector,
                                    Collection<SearchGroup<T>> groups,
                                    Sort groupSort,
                                    Sort withinGroupSort,
                                    int maxDocsPerGroup,
                                    boolean getMaxScores)

      Create a new TopGroupsCollector
      Parameters:
        `groupSelector` - the group selector used to define groups
        `groups` - the groups to collect TopDocs for
        `groupSort` - the order in which groups are returned
        `withinGroupSort` - the order in which documents are sorted in each group
        `maxDocsPerGroup` - the maximum number of docs to collect for each group
        `getMaxScores` - if true, record the maximum score for each group

  - ### Method Detail

    - #### getTopGroups

          public TopGroups<T> getTopGroups(int withinGroupOffset)

      Get the TopGroups recorded by this collector
      Parameters:
        `withinGroupOffset` - the offset within each group to start collecting documents

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