Class BlendedTermQuery


public abstract class BlendedTermQuery
BlendedTermQuery can be used to unify term statistics across one or more fields in the index. A common problem with structured documents is that a term that is significant in on field might not be significant in other fields like in a scenario where documents represent users with a "first_name" and a "second_name". When someone searches for "simon" it will very likely get "paul simon" first since "simon" is a an uncommon last name ie. has a low document frequency. This query tries to "lie" about the global statistics like document frequency as well total term frequency to rank based on the estimated statistics.

While aggregating the total term frequency is trivial since it can be summed up not every Similarity makes use of this statistic. The document frequency which is used in the ClassicSimilarity can only be estimated as an lower-bound since it is a document based statistic. For the document frequency the maximum frequency across all fields per term is used which is the minimum number of documents the terms occurs in.

  • Constructor Summary

    Constructor Description
    BlendedTermQuery​(org.apache.lucene.index.Term[] terms, float[] boosts)  
  • Method Summary

    Modifier and Type Method Description
    protected void blend​(org.apache.lucene.index.TermStates[] contexts, int maxDoc, org.apache.lucene.index.IndexReader reader)  
    static BlendedTermQuery commonTermsBlendedQuery​(org.apache.lucene.index.Term[] terms, float[] boosts, float maxTermFrequency)
    Since max_score optimization landed in 7.0, normal MultiMatchQuery will achieve the same result without any configuration.
    static BlendedTermQuery dismaxBlendedQuery​(org.apache.lucene.index.Term[] terms, float tieBreakerMultiplier)  
    static BlendedTermQuery dismaxBlendedQuery​(org.apache.lucene.index.Term[] terms, float[] boosts, float tieBreakerMultiplier)  
    boolean equals​(java.lang.Object o)  
    java.util.List<org.apache.lucene.index.Term> getTerms()  
    int hashCode() rewrite​(org.apache.lucene.index.IndexReader reader)  
    protected abstract topLevelQuery​(org.apache.lucene.index.Term[] terms, org.apache.lucene.index.TermStates[] ctx, int[] docFreqs, int maxDoc)  
    java.lang.String toString​(java.lang.String field)  
    void visit​( visitor)  

    Methods inherited from class

    classHash, createWeight, sameClassAs, toString

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait
  • Constructor Details

    • BlendedTermQuery

      public BlendedTermQuery​(org.apache.lucene.index.Term[] terms, float[] boosts)
  • Method Details

    • rewrite

      public rewrite​(org.apache.lucene.index.IndexReader reader) throws
      rewrite in class
    • topLevelQuery

      protected abstract topLevelQuery​(org.apache.lucene.index.Term[] terms, org.apache.lucene.index.TermStates[] ctx, int[] docFreqs, int maxDoc)
    • blend

      protected void blend​(org.apache.lucene.index.TermStates[] contexts, int maxDoc, org.apache.lucene.index.IndexReader reader) throws
    • getTerms

      public java.util.List<org.apache.lucene.index.Term> getTerms()
    • toString

      public java.lang.String toString​(java.lang.String field)
      Specified by:
      toString in class
    • visit

      public void visit​( visitor)
      visit in class
    • equals

      public boolean equals​(java.lang.Object o)
      Specified by:
      equals in class
    • hashCode

      public int hashCode()
      Specified by:
      hashCode in class
    • commonTermsBlendedQuery

      @Deprecated public static BlendedTermQuery commonTermsBlendedQuery​(org.apache.lucene.index.Term[] terms, float[] boosts, float maxTermFrequency)
      Since max_score optimization landed in 7.0, normal MultiMatchQuery will achieve the same result without any configuration.
    • dismaxBlendedQuery

      public static BlendedTermQuery dismaxBlendedQuery​(org.apache.lucene.index.Term[] terms, float tieBreakerMultiplier)
    • dismaxBlendedQuery

      public static BlendedTermQuery dismaxBlendedQuery​(org.apache.lucene.index.Term[] terms, float[] boosts, float tieBreakerMultiplier)