org.apache.lucene.search

## Class MultiTermQuery.TopTermsBlendedFreqScoringRewrite

- java.lang.Object
- - org.apache.lucene.search.MultiTermQuery.RewriteMethod
  - - org.apache.lucene.search.TopTermsRewrite<BlendedTermQuery.Builder>
    - - org.apache.lucene.search.MultiTermQuery.TopTermsBlendedFreqScoringRewrite

- Enclosing class:
    MultiTermQuery

      public static final class MultiTermQuery.TopTermsBlendedFreqScoringRewrite
      extends TopTermsRewrite<BlendedTermQuery.Builder>

  A rewrite method that first translates each term into `BooleanClause.Occur.SHOULD` clause in a BooleanQuery, but adjusts the frequencies used for scoring to be blended across the terms, otherwise the rarest term typically ranks highest (often not useful eg in the set of expanded terms in a FuzzyQuery).

  This rewrite method only uses the top scoring terms so it will not overflow the boolean max clause count.

  See Also:
    `MultiTermQuery.setRewriteMethod(org.apache.lucene.search.MultiTermQuery.RewriteMethod)`

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TopTermsBlendedFreqScoringRewrite(int size)` Create a TopTermsBlendedScoringBooleanQueryRewrite for at most `size` terms.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected void` | `addClause(BlendedTermQuery.Builder topLevel, Term term, int docCount, float boost, TermContext states)`
    `protected void` | `addClause(B topLevel, Term term, int docCount, float boost)` Add a MultiTermQuery term to the top-level query builder.
    `protected Query` | `build(BlendedTermQuery.Builder builder)` Finalize the creation of the query from the builder.
    `protected int` | `getMaxSize()` return the maximum size of the priority queue (for boolean rewrites this is BooleanQuery#getMaxClauseCount).
    `protected BlendedTermQuery.Builder` | `getTopLevelBuilder()` Return a suitable builder for the top-level Query for holding all expanded terms.

    - ### Methods inherited from class org.apache.lucene.search.TopTermsRewrite

      `equals, getSize, hashCode, rewrite`

    - ### Methods inherited from class org.apache.lucene.search.MultiTermQuery.RewriteMethod

      `getTermsEnum`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### TopTermsBlendedFreqScoringRewrite

          public TopTermsBlendedFreqScoringRewrite(int size)

      Create a TopTermsBlendedScoringBooleanQueryRewrite for at most `size` terms.

      NOTE: if `BooleanQuery.getMaxClauseCount()` is smaller than `size`, then it will be used instead.

  - ### Method Detail

    - #### getMaxSize

          protected int getMaxSize()

      Description copied from class: `TopTermsRewrite`
      return the maximum size of the priority queue (for boolean rewrites this is BooleanQuery#getMaxClauseCount).
      Specified by:
        `getMaxSize` in class `TopTermsRewrite<BlendedTermQuery.Builder>`

    - #### getTopLevelBuilder

          protected BlendedTermQuery.Builder getTopLevelBuilder()

      Return a suitable builder for the top-level Query for holding all expanded terms.

    - #### build

          protected Query build(BlendedTermQuery.Builder builder)

      Finalize the creation of the query from the builder.

    - #### addClause

          protected void addClause(BlendedTermQuery.Builder topLevel,
                                   Term term,
                                   int docCount,
                                   float boost,
                                   TermContext states)

    - #### addClause

          protected final void addClause(B topLevel,
                                         Term term,
                                         int docCount,
                                         float boost)
                                  throws IOException

      Add a MultiTermQuery term to the top-level query builder.
      Throws:
        `IOException`

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