Class TermScorer


  • public final class TermScorer
    extends Scorer
    Expert: A Scorer for documents matching a Term.
    • 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 java.io.IOException
        Returns term frequency in the current document.
        Throws:
        java.io.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
      • score

        public float score()
                    throws java.io.IOException
        Description copied from class: Scorable
        Returns the score of the current document matching the query.
        Specified by:
        score in class Scorable
        Throws:
        java.io.IOException
      • smoothingScore

        public float smoothingScore​(int docId)
                             throws java.io.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:
        java.io.IOException
      • advanceShallow

        public int advanceShallow​(int target)
                           throws java.io.IOException
        Description copied from class: Scorer
        Advance to the block of documents that contains target in order to get scoring information about this block. This method is implicitly called by DocIdSetIterator.advance(int) and DocIdSetIterator.nextDoc() on the returned doc ID. Calling this method doesn't modify the current DocIdSetIterator.docID(). It returns a number that is greater than or equal to all documents contained in the current block, but less than any doc IDS of the next block. target must be >= Scorable.docID() as well as all targets that have been passed to Scorer.advanceShallow(int) so far.
        Overrides:
        advanceShallow in class Scorer
        Throws:
        java.io.IOException
      • getMaxScore

        public float getMaxScore​(int upTo)
                          throws java.io.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:
        java.io.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 java.lang.String toString()
        Returns a string representation of this TermScorer.
        Overrides:
        toString in class java.lang.Object