Module org.apache.lucene.grouping
Package org.apache.lucene.search.grouping

Class AllGroupsCollector<T>

java.lang.Object
org.apache.lucene.search.SimpleCollector
org.apache.lucene.search.grouping.AllGroupsCollector<T>
All Implemented Interfaces:
Collector, LeafCollector
public class AllGroupsCollector<T> extends SimpleCollector
A collector that collects all groups that match the query. Only the group value is collected, and the order is undefined. This collector does not determine the most relevant document of a group.

  • Field Details

    • groupSelector

      private final GroupSelector<T> groupSelector

    • groups

      private final Set<T> groups

  • Constructor Details

    • AllGroupsCollector

      public AllGroupsCollector(GroupSelector<T> groupSelector)
      Create a new AllGroupsCollector
      Parameters:
      groupSelector - the GroupSelector to determine groups

  • Method Details

    • getGroupCount

      public int getGroupCount()
      Returns the total number of groups for the executed search. This is a convenience method. The following code snippet has the same effect: 
      getGroups().size()
      Returns:
      The total number of groups for the executed search

    • getGroups

      public Collection<T> getGroups()
      Returns the group values

      This is an unordered collections of group values.

      Returns:
      the group values

    • setScorer

      public void setScorer(Scorable scorer) throws IOException
      Description copied from interface: LeafCollector
      Called before successive calls to LeafCollector.collect(int). Implementations that need the score of the current document (passed-in to LeafCollector.collect(int)), should save the passed-in Scorer and call scorer.score() when needed.
      Specified by:
      setScorer in interface LeafCollector
      Overrides:
      setScorer in class SimpleCollector
      Throws:
      IOException

    • doSetNextReader

      protected void doSetNextReader(LeafReaderContext context) throws IOException
      Description copied from class: SimpleCollector
      This method is called before collecting context.
      Overrides:
      doSetNextReader in class SimpleCollector
      Throws:
      IOException

    • collect

      public void collect(int doc) throws IOException
      Description copied from interface: LeafCollector
      Called once for every document matching a query, with the unbased document number.

      Note: The collection of the current segment can be terminated by throwing a CollectionTerminatedException. In this case, the last docs of the current LeafReaderContext will be skipped and IndexSearcher will swallow the exception and continue collection with the next leaf.

      Note: This is called in an inner search loop. For good search performance, implementations of this method should not call StoredFields.document(int) on every hit. Doing so can slow searches by an order of magnitude or more.

      Specified by:
      collect in interface LeafCollector
      Specified by:
      collect in class SimpleCollector
      Throws:
      IOException

    • scoreMode

      public ScoreMode scoreMode()
      Description copied from interface: Collector
      Indicates what features are required from the scorer.