Package org.apache.lucene.search

Class AbstractKnnCollector

java.lang.Object
org.apache.lucene.search.AbstractKnnCollector
All Implemented Interfaces:
KnnCollector
Direct Known Subclasses:
TopKnnCollector
public abstract class AbstractKnnCollector extends Object implements KnnCollector
AbstractKnnCollector is the default implementation for a knn collector used for gathering kNN results and providing topDocs from the gathered neighbors

  • Constructor Details

    • AbstractKnnCollector

      protected AbstractKnnCollector(int k, long visitLimit)

  • Method Details

    • earlyTerminated

      public final boolean earlyTerminated()
      Description copied from interface: KnnCollector
      If search visits too many documents, the results collector will terminate early. Usually, this is due to some restricted filter on the document set.

      When collection is earlyTerminated, the results are not a correct representation of k nearest neighbors.

      Specified by:
      earlyTerminated in interface KnnCollector
      Returns:
      is the current result set marked as incomplete?

    • incVisitedCount

      public final void incVisitedCount(int count)
      Specified by:
      incVisitedCount in interface KnnCollector
      Parameters:
      count - increments the visited vector count, must be greater than 0.

    • visitedCount

      public final long visitedCount()
      Specified by:
      visitedCount in interface KnnCollector
      Returns:
      the current visited vector count

    • visitLimit

      public final long visitLimit()
      Specified by:
      visitLimit in interface KnnCollector
      Returns:
      the visited vector limit

    • k

      public final int k()
      Specified by:
      k in interface KnnCollector
      Returns:
      the expected number of collected results

    • collect

      public abstract boolean collect(int docId, float similarity)
      Description copied from interface: KnnCollector
      Collect the provided docId and include in the result set.
      Specified by:
      collect in interface KnnCollector
      Parameters:
      docId - of the vector to collect
      similarity - its calculated similarity
      Returns:
      true if the vector is collected

    • minCompetitiveSimilarity

      public abstract float minCompetitiveSimilarity()
      Description copied from interface: KnnCollector
      This method is utilized during search to ensure only competitive results are explored.

      Consequently, if this results collector wants to collect `k` results, this should return Float.NEGATIVE_INFINITY when not full.

      When full, the minimum score should be returned.

      Specified by:
      minCompetitiveSimilarity in interface KnnCollector
      Returns:
      the current minimum competitive similarity in the collection

    • topDocs

      public abstract TopDocs topDocs()
      Description copied from interface: KnnCollector
      This drains the collected nearest kNN results and returns them in a new TopDocs collection, ordered by score descending. NOTE: This is generally a destructive action and the collector should not be used after topDocs() is called.
      Specified by:
      topDocs in interface KnnCollector
      Returns:
      The collected top documents