Class TermScorer


  • public final class TermScorer
    extends Scorer
    Expert: A Scorer for documents matching a Term.
    NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
    • Method Detail

      • docID

        public int docID()
        Description copied from class: Scorable
        Returns the doc ID that is currently being scored.
        Specified by:
        docID in class Scorable
      • freq

        public final int freq()
                       throws IOException
        Returns term frequency in the current document.
        Throws:
        IOException
      • iterator

        public DocIdSetIterator iterator()
        Description copied from class: Scorer
        Return a DocIdSetIterator over matching documents.

        The returned iterator will either be positioned on -1 if no documents have been scored yet, DocIdSetIterator.NO_MORE_DOCS if all documents have been scored already, or the last document id that has been scored otherwise.

        The returned iterator is a view: calling this method several times will return iterators that have the same state.

        Specified by:
        iterator in class Scorer
      • smoothingScore

        public float smoothingScore​(int docId)
                             throws IOException
        Description copied from class: Scorable
        Returns the smoothing score of the current document matching the query. This score is used when the query/term does not appear in the document, and behaves like an idf. The smoothing score is particularly important when the Scorer returns a product of probabilities so that the document score does not go to zero when one probability is zero. This can return 0 or a smoothing score.

        Smoothing scores are described in many papers, including: Metzler, D. and Croft, W. B. , "Combining the Language Model and Inference Network Approaches to Retrieval," Information Processing and Management Special Issue on Bayesian Networks and Information Retrieval, 40(5), pp.735-750.

        Overrides:
        smoothingScore in class Scorable
        Throws:
        IOException
      • getMaxScore

        public float getMaxScore​(int upTo)
                          throws IOException
        Description copied from class: Scorer
        Return the maximum score that documents between the last target that this iterator was shallow-advanced to included and upTo included.
        Specified by:
        getMaxScore in class Scorer
        Throws:
        IOException
      • setMinCompetitiveScore

        public void setMinCompetitiveScore​(float minScore)
        Description copied from class: Scorable
        Optional method: Tell the scorer that its iterator may safely ignore all documents whose score is less than the given minScore. This is a no-op by default.

        This method may only be called from collectors that use ScoreMode.TOP_SCORES, and successive calls may only set increasing values of minScore.

        Overrides:
        setMinCompetitiveScore in class Scorable
      • toString

        public String toString()
        Returns a string representation of this TermScorer.
        Overrides:
        toString in class Object