Package org.apache.lucene.search

Class Query

java.lang.Object
org.apache.lucene.search.Query
Direct Known Subclasses:
BlendedTermQuery, BooleanQuery, BoostQuery, ConstantScoreQuery, DisjunctionMaxQuery, FieldExistsQuery, IndexOrDocValuesQuery, IndexSortSortedNumericDocValuesRangeQuery, IndriQuery, KnnByteVectorQuery, KnnFloatVectorQuery, MatchAllDocsQuery, MatchNoDocsQuery, MultiPhraseQuery, MultiTermQuery, NGramPhraseQuery, PhraseQuery, PointInSetQuery, PointRangeQuery, RangeFieldQuery, SynonymQuery, TermQuery, XYDocValuesPointInGeometryQuery
public abstract class Query extends Object
The abstract base class for queries.

Instantiable subclasses are:

See also additional queries available in the Queries module.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Query()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected final int
    classHash()
    Provides a constant integer for a given class, derived from the name of the class.
    Weight
    createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost)
    Expert: Constructs an appropriate Weight implementation for this query.
    abstract boolean
    equals(Object obj)
    Override and implement query instance equivalence properly in a subclass.
    abstract int
    hashCode()
    Override and implement query hash code properly in a subclass.
    Query
    rewrite(IndexReader reader)
    Deprecated.
    Use rewrite(IndexSearcher)
    Query
    rewrite(IndexSearcher indexSearcher)
    Expert: called to re-write queries into primitive queries.
    protected final boolean
    sameClassAs(Object other)
    Utility method to check whether other is not null and is exactly of the same class as this object's class.
    final String
    toString()
    Prints a query to a string.
    abstract String
    toString(String field)
    Prints a query to a string, with field assumed to be the default field and omitted.
    abstract void
    visit(QueryVisitor visitor)
    Recurse through the query tree, visiting any child queries.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • Query

      public Query()

  • Method Details

    • toString

      public abstract String toString(String field)
      Prints a query to a string, with field assumed to be the default field and omitted.

    • toString

      public final String toString()
      Prints a query to a string.
      Overrides:
      toString in class Object

    • createWeight

      public Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException
      Expert: Constructs an appropriate Weight implementation for this query.

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

      Parameters:
      scoreMode - How the produced scorers will be consumed.
      boost - The boost that is propagated by the parent queries.
      Throws:
      IOException

    • rewrite

      @Deprecated public Query rewrite(IndexReader reader) throws IOException
      Deprecated.
      Use rewrite(IndexSearcher)
      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.

      Throws:
      IOException
      See Also:

    • rewrite

      public Query rewrite(IndexSearcher indexSearcher) throws IOException
      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.

      The rewrite process may be able to make use of IndexSearcher's executor and be executed in parallel if the executor is provided.

      However, if any of the intermediary queries do not satisfy the new API, parallel rewrite is not possible for any subsequent sub-queries. To take advantage of this API, the entire query tree must override this method.

      Throws:
      IOException
      See Also:

    • visit

      public abstract void visit(QueryVisitor visitor)
      Recurse through the query tree, visiting any child queries.
      Parameters:
      visitor - a QueryVisitor to be called by each query in the tree

    • equals

      public abstract boolean equals(Object obj)
      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 to those of the other instance. Utility methods are provided for certain repetitive code.

      Overrides:
      equals in class Object
      See Also:

    • hashCode

      public abstract int hashCode()
      Override and implement query hash code properly in a subclass. This is required so that QueryCache works properly.
      Overrides:
      hashCode in class Object
      See Also:

    • sameClassAs

      protected final boolean sameClassAs(Object other)
      Utility method to check whether other is not null and is exactly of the same class as this object's class.

      When this method is used in an implementation of equals(Object), consider using classHash() in the implementation of hashCode() to differentiate different class.

    • classHash

      protected final int classHash()
      Provides a constant integer for a given class, derived from the name of the class. The rationale for not using just Object.hashCode() is that classes may be assigned different hash codes for each execution and we want hashes to be possibly consistent to facilitate debugging.