Package org.apache.lucene.search

Class Scorable

java.lang.Object
org.apache.lucene.search.Scorable
Direct Known Subclasses:
FilterScorable, ScoreCachingWrappingScorer, Scorer
public abstract class Scorable extends Object
Allows access to the score of a Query

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    Scorable.ChildScorable
    A child Scorer and its relationship to its parent.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Scorable()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    abstract int
    docID()
    Returns the doc ID that is currently being scored.
    Collection<Scorable.ChildScorable>
    getChildren()
    Returns child sub-scorers positioned on the current document
    abstract float
    score()
    Returns the score of the current document matching the query.
    void
    setMinCompetitiveScore(float minScore)
    Optional method: Tell the scorer that its iterator may safely ignore all documents whose score is less than the given minScore.
    float
    smoothingScore(int docId)
    Returns the smoothing score of the current document matching the query.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • Scorable

      public Scorable()

  • Method Details

    • score

      public abstract float score() throws IOException
      Returns the score of the current document matching the query.
      Throws:
      IOException

    • smoothingScore

      public float smoothingScore(int docId) throws IOException
      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.

      Throws:
      IOException

    • docID

      public abstract int docID()
      Returns the doc ID that is currently being scored.

    • setMinCompetitiveScore

      public void setMinCompetitiveScore(float minScore) throws IOException
      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.

      Throws:
      IOException

    • getChildren

      public Collection<Scorable.ChildScorable> getChildren() throws IOException
      Returns child sub-scorers positioned on the current document
      Throws:
      IOException
      WARNING: This API is experimental and might change in incompatible ways in the next release.