Package org.apache.lucene.search

Class TopFieldCollector

java.lang.Object
org.apache.lucene.search.TopDocsCollector<FieldValueHitQueue.Entry>
org.apache.lucene.search.TopFieldCollector
All Implemented Interfaces:
Collector
public abstract class TopFieldCollector extends TopDocsCollector<FieldValueHitQueue.Entry>
A Collector that sorts by SortField using FieldComparators.

See the create(org.apache.lucene.search.Sort, int, int) method for instantiating a TopFieldCollector.

WARNING: This API is experimental and might change in incompatible ways in the next release.

  • Method Details

    • scoreMode

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

    • updateGlobalMinCompetitiveScore

      protected void updateGlobalMinCompetitiveScore(Scorable scorer) throws IOException
      Throws:
      IOException

    • updateMinCompetitiveScore

      protected void updateMinCompetitiveScore(Scorable scorer) throws IOException
      Throws:
      IOException

    • create

      public static TopFieldCollector create(Sort sort, int numHits, int totalHitsThreshold)
      Creates a new TopFieldCollector from the given arguments.

      NOTE: The instances returned by this method pre-allocate a full array of length numHits.

      Parameters:
      sort - the sort criteria (SortFields).
      numHits - the number of results to collect.
      totalHitsThreshold - the number of docs to count accurately. If the query matches more than totalHitsThreshold hits then its hit count will be a lower bound. On the other hand if the query matches less than or exactly totalHitsThreshold hits then the hit count of the result will be accurate. Integer.MAX_VALUE may be used to make the hit count accurate, but this will also make query processing slower.
      Returns:
      a TopFieldCollector instance which will sort the results by the sort criteria.

    • create

      public static TopFieldCollector create(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold)
      Creates a new TopFieldCollector from the given arguments.

      NOTE: The instances returned by this method pre-allocate a full array of length numHits.

      Parameters:
      sort - the sort criteria (SortFields).
      numHits - the number of results to collect.
      after - only hits after this FieldDoc will be collected
      totalHitsThreshold - the number of docs to count accurately. If the query matches more than totalHitsThreshold hits then its hit count will be a lower bound. On the other hand if the query matches less than or exactly totalHitsThreshold hits then the hit count of the result will be accurate. Integer.MAX_VALUE may be used to make the hit count accurate, but this will also make query processing slower. Setting totalHitsThreshold less than Integer.MAX_VALUE instructs Lucene to skip non-competitive documents whenever possible. For numeric sort fields the skipping functionality works when the same field is indexed both with doc values and points. In this case, there is an assumption that the same data is stored in these points and doc values.
      Returns:
      a TopFieldCollector instance which will sort the results by the sort criteria.

    • createSharedManager

      public static CollectorManager<TopFieldCollector,TopFieldDocs> createSharedManager(Sort sort, int numHits, FieldDoc after, int totalHitsThreshold)
      Create a CollectorManager which uses a shared hit counter to maintain number of hits and a shared MaxScoreAccumulator to propagate the minimum score accross segments if the primary sort is by relevancy.

    • populateScores

      public static void populateScores(ScoreDoc[] topDocs, IndexSearcher searcher, Query query) throws IOException
      Populate scores of the given topDocs.
      Parameters:
      topDocs - the top docs to populate
      searcher - the index searcher that has been used to compute topDocs
      query - the query that has been used to compute topDocs
      Throws:
      IllegalArgumentException - if there is evidence that topDocs have been computed against a different searcher or a different query.
      IOException
      WARNING: This API is experimental and might change in incompatible ways in the next release.

    • populateResults

      protected void populateResults(ScoreDoc[] results, int howMany)
      Description copied from class: TopDocsCollector
      Populates the results array with the ScoreDoc instances. This can be overridden in case a different ScoreDoc type should be returned.
      Overrides:
      populateResults in class TopDocsCollector<FieldValueHitQueue.Entry>

    • newTopDocs

      protected TopDocs newTopDocs(ScoreDoc[] results, int start)
      Description copied from class: TopDocsCollector
      Returns a TopDocs instance containing the given results. If results is null it means there are no results to return, either because there were 0 calls to collect() or because the arguments to topDocs were invalid.
      Overrides:
      newTopDocs in class TopDocsCollector<FieldValueHitQueue.Entry>

    • topDocs

      public TopFieldDocs topDocs()
      Description copied from class: TopDocsCollector
      Returns the top docs that were collected by this collector.
      Overrides:
      topDocs in class TopDocsCollector<FieldValueHitQueue.Entry>

    • isEarlyTerminated

      public boolean isEarlyTerminated()
      Return whether collection terminated early.