org.apache.lucene.search

## Class TermInSetQuery

- java.lang.Object
- - org.apache.lucene.search.Query
  - - org.apache.lucene.search.TermInSetQuery

- All Implemented Interfaces:
    Accountable

      public class TermInSetQuery
      extends Query
      implements Accountable

  Specialization for a disjunction over many terms that behaves like a `ConstantScoreQuery` over a `BooleanQuery` containing only `BooleanClause.Occur.SHOULD` clauses.

  For instance in the following example, both @{code q1} and `q2` would yield the same scores:

       Query q1 = new TermInSetQuery(new Term("field", "foo"), new Term("field", "bar"));

       BooleanQuery bq = new BooleanQuery();
       bq.add(new TermQuery(new Term("field", "foo")), Occur.SHOULD);
       bq.add(new TermQuery(new Term("field", "bar")), Occur.SHOULD);
       Query q2 = new ConstantScoreQuery(bq);

  When there are few terms, this query executes like a regular disjunction. However, when there are many terms, instead of merging iterators on the fly, it will populate a bit set with matching docs and return a `Scorer` over this bit set.

  NOTE: This query produces scores that are equal to its boost

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TermInSetQuery(String field, BytesRef... terms)` Creates a new `TermInSetQuery` from the given array of terms.
    `TermInSetQuery(String field, Collection<BytesRef> terms)` Creates a new `TermInSetQuery` from the given collection of terms.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Weight` | `createWeight(IndexSearcher searcher, boolean needsScores)` Expert: Constructs an appropriate Weight implementation for this query.
    `boolean` | `equals(Object other)` Override and implement query instance equivalence properly in a subclass.
    `Collection<Accountable>` | `getChildResources()` Returns nested resources of this class.
    `PrefixCodedTerms` | `getTermData()` Returns the terms wrapped in a PrefixCodedTerms.
    `int` | `hashCode()` Override and implement query hash code properly in a subclass.
    `long` | `ramBytesUsed()` Return the memory usage of this object in bytes.
    `Query` | `rewrite(IndexReader reader)` Expert: called to re-write queries into primitive queries.
    `String` | `toString(String defaultField)` Prints a query to a string, with `field` assumed to be the default field and omitted.

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

      `classHash, sameClassAs, toString`

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

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

- - ### Constructor Detail

    - #### TermInSetQuery

          public TermInSetQuery(String field,
                                Collection<BytesRef> terms)

      Creates a new `TermInSetQuery` from the given collection of terms.

    - #### TermInSetQuery

          public TermInSetQuery(String field,
                                BytesRef... terms)

      Creates a new `TermInSetQuery` from the given array of terms.

  - ### Method Detail

    - #### rewrite

          public Query rewrite(IndexReader reader)
                        throws IOException

      Description copied from class: `Query`
      Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
      Overrides:
        `rewrite` in class `Query`
      Throws:
        `IOException`

    - #### equals

          public boolean equals(Object other)

      Description copied from class: `Query`
      Override and implement query instance equivalence properly in a subclass. This is required so that `QueryCache` works properly. Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical that other instance. Utility methods are provided for certain repetitive code.
      Specified by:
        `equals` in class `Query`
      See Also:
        `Query.sameClassAs(Object)`, `Query.classHash()`

    - #### hashCode

          public int hashCode()

      Description copied from class: `Query`
      Override and implement query hash code properly in a subclass. This is required so that `QueryCache` works properly.
      Specified by:
        `hashCode` in class `Query`
      See Also:
        `Query.equals(Object)`

    - #### getTermData

          public PrefixCodedTerms getTermData()

      Returns the terms wrapped in a PrefixCodedTerms.

    - #### toString

          public String toString(String defaultField)

      Description copied from class: `Query`
      Prints a query to a string, with `field` assumed to be the default field and omitted.
      Specified by:
        `toString` in class `Query`

    - #### ramBytesUsed

          public long ramBytesUsed()

      Description copied from interface: `Accountable`
      Return the memory usage of this object in bytes. Negative values are illegal.
      Specified by:
        `ramBytesUsed` in interface `Accountable`

    - #### getChildResources

          public Collection<Accountable> getChildResources()

      Description copied from interface: `Accountable`
      Returns nested resources of this class. The result should be a point-in-time snapshot (to avoid race conditions).
      Specified by:
        `getChildResources` in interface `Accountable`
      See Also:
        `Accountables`

    - #### createWeight

          public Weight createWeight(IndexSearcher searcher,
                                     boolean needsScores)
                              throws IOException

      Description copied from class: `Query`
      Expert: Constructs an appropriate Weight implementation for this query.

      Only implemented by primitive queries, which re-write to themselves.

      Overrides:
        `createWeight` in class `Query`
        `needsScores` - True if document scores (`Scorer.score()`) or match frequencies (`Scorer.freq()`) are needed.
      Throws:
        `IOException`

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