org.apache.lucene.search

## Class BooleanQuery

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

- All Implemented Interfaces:
    Iterable<BooleanClause>

      public class BooleanQuery
      extends Query
      implements Iterable<BooleanClause>

  A Query that matches documents matching boolean combinations of other queries, e.g. `TermQuery`s, `PhraseQuery`s or other BooleanQuerys.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `BooleanQuery.Builder` A builder for boolean queries.
    `static class` | `BooleanQuery.TooManyClauses` Thrown when an attempt is made to add more than `getMaxClauseCount()` clauses.

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `List<BooleanClause>` | `clauses()` Return a list of the clauses of this `BooleanQuery`.
    `Weight` | `createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)` Expert: Constructs an appropriate Weight implementation for this query.
    `boolean` | `equals(Object o)` Compares the specified object with this boolean query for equality.
    `static int` | `getMaxClauseCount()` Return the maximum number of clauses permitted, 1024 by default.
    `int` | `getMinimumNumberShouldMatch()` Gets the minimum number of the optional BooleanClauses which must be satisfied.
    `int` | `hashCode()` Override and implement query hash code properly in a subclass.
    `Iterator<BooleanClause>` | `iterator()` Returns an iterator on the clauses in this query.
    `Query` | `rewrite(IndexReader reader)` Expert: called to re-write queries into primitive queries.
    `static void` | `setMaxClauseCount(int maxClauseCount)` Set the maximum number of clauses permitted per BooleanQuery.
    `String` | `toString(String field)` Prints a user-readable version of this query.
    `void` | `visit(QueryVisitor visitor)` Recurse through the query tree, visiting any child queries

    - ### 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`

    - ### Methods inherited from interface java.lang.Iterable

      `forEach, spliterator`

- - ### Method Detail

    - #### getMaxClauseCount

          public static int getMaxClauseCount()

      Return the maximum number of clauses permitted, 1024 by default. Attempts to add more than the permitted number of clauses cause `BooleanQuery.TooManyClauses` to be thrown.
      See Also:
        `setMaxClauseCount(int)`

    - #### setMaxClauseCount

          public static void setMaxClauseCount(int maxClauseCount)

      Set the maximum number of clauses permitted per BooleanQuery. Default value is 1024.

    - #### getMinimumNumberShouldMatch

          public int getMinimumNumberShouldMatch()

      Gets the minimum number of the optional BooleanClauses which must be satisfied.

    - #### clauses

          public List<BooleanClause> clauses()

      Return a list of the clauses of this `BooleanQuery`.

    - #### iterator

          public final Iterator<BooleanClause> iterator()

      Returns an iterator on the clauses in this query. It implements the `Iterable` interface to make it possible to do:

          for (BooleanClause clause : booleanQuery) {}

      Specified by:
        `iterator` in interface `Iterable<BooleanClause>`

    - #### createWeight

          public Weight createWeight(IndexSearcher searcher,
                                     ScoreMode scoreMode,
                                     float boost)
                              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`
        `scoreMode` - How the produced scorers will be consumed.
        `boost` - The boost that is propagated by the parent queries.
      Throws:
        `IOException`

    - #### 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.

      Callers are expected to call `rewrite` multiple times if necessary, until the rewritten query is the same as the original query.

      Overrides:
        `rewrite` in class `Query`
      Throws:
        `IOException`
      See Also:
        `IndexSearcher.rewrite(Query)`

    - #### visit

          public void visit(QueryVisitor visitor)

      Description copied from class: `Query`
      Recurse through the query tree, visiting any child queries
      Overrides:
        `visit` in class `Query`
      Parameters:
        `visitor` - a QueryVisitor to be called by each query in the tree

    - #### toString

          public String toString(String field)

      Prints a user-readable version of this query.
      Specified by:
        `toString` in class `Query`

    - #### equals

          public boolean equals(Object o)

      Compares the specified object with this boolean query for equality. Returns true if and only if the provided object
      - is also a `BooleanQuery`,
      - has the same value of `getMinimumNumberShouldMatch()`
      - has the same `BooleanClause.Occur.SHOULD` clauses, regardless of the order
      - has the same `BooleanClause.Occur.MUST` clauses, regardless of the order
      - has the same set of `BooleanClause.Occur.FILTER` clauses, regardless of the order and regardless of duplicates
      - has the same set of `BooleanClause.Occur.MUST_NOT` clauses, regardless of the order and regardless of duplicates
      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)`

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