Module org.elasticsearch.server
Package org.elasticsearch.lucene.queries

Class BlendedTermQuery

java.lang.Object
org.apache.lucene.search.Query
org.elasticsearch.lucene.queries.BlendedTermQuery
public abstract class BlendedTermQuery extends org.apache.lucene.search.Query
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

    Constructors
    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
    dismaxBlendedQuery(org.apache.lucene.index.Term[] terms, float tieBreakerMultiplier)
     
    static BlendedTermQuery
    dismaxBlendedQuery(org.apache.lucene.index.Term[] terms, float[] boosts, float tieBreakerMultiplier)
     
    boolean
    equals(Object o)
     
    List<org.apache.lucene.index.Term>
    getTerms()
     
    int
    hashCode()
     
    org.apache.lucene.search.Query
    rewrite(org.apache.lucene.index.IndexReader reader)
     
    protected abstract org.apache.lucene.search.Query
    topLevelQuery(org.apache.lucene.index.Term[] terms, org.apache.lucene.index.TermStates[] ctx, int[] docFreqs, int maxDoc)
     
    String
    toString(String field)
     
    void
    visit(org.apache.lucene.search.QueryVisitor visitor)
     

    Methods inherited from class org.apache.lucene.search.Query

    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 org.apache.lucene.search.Query rewrite(org.apache.lucene.index.IndexReader reader) throws IOException
      Overrides:
      rewrite in class org.apache.lucene.search.Query
      Throws:
      IOException

    • topLevelQuery

      protected abstract org.apache.lucene.search.Query 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 IOException
      Throws:
      IOException

    • getTerms

      public List<org.apache.lucene.index.Term> getTerms()

    • toString

      public String toString(String field)
      Specified by:
      toString in class org.apache.lucene.search.Query

    • visit

      public void visit(org.apache.lucene.search.QueryVisitor visitor)
      Specified by:
      visit in class org.apache.lucene.search.Query

    • equals

      public boolean equals(Object o)
      Specified by:
      equals in class org.apache.lucene.search.Query

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in class org.apache.lucene.search.Query

    • 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)