org.apache.lucene.queries

Class BlendedTermQuery

  • All Implemented Interfaces:
    Cloneable 

    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 DefaultSimilarity 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 and Description
      BlendedTermQuery(org.apache.lucene.index.Term[] terms)
       

    • Constructor Detail

      • BlendedTermQuery

        public BlendedTermQuery(org.apache.lucene.index.Term[] terms)

    • Method Detail

      • 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.TermContext[] ctx,
                                                                int[] docFreqs,
                                                                int maxDoc)

      • blend

        protected void blend(org.apache.lucene.index.TermContext[] contexts,
                     int maxDoc,
                     org.apache.lucene.index.IndexReader reader)
              throws IOException
        Throws:
        IOException

      • extractTerms

        public void extractTerms(Set<org.apache.lucene.index.Term> terms)

      • equals

        public boolean equals(Object o)

      • hashCode

        public int hashCode()

      • booleanBlendedQuery

        public static BlendedTermQuery booleanBlendedQuery(org.apache.lucene.index.Term[] terms,
                                                   boolean disableCoord)

      • booleanBlendedQuery

        public static BlendedTermQuery booleanBlendedQuery(org.apache.lucene.index.Term[] terms,
                                                   float[] boosts,
                                                   boolean disableCoord)

      • commonTermsBlendedQuery

        public static BlendedTermQuery commonTermsBlendedQuery(org.apache.lucene.index.Term[] terms,
                                                       float[] boosts,
                                                       boolean disableCoord,
                                                       float maxTermFrequency)

      • 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)