Class Query

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int CLASS_NAME_HASH  
    • Constructor Summary

      Constructors 
      Constructor Description
      Query()  
    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      protected 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​(java.lang.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)
      Expert: called to re-write queries into primitive queries.
      protected boolean sameClassAs​(java.lang.Object other)
      Utility method to check whether other is not null and is exactly of the same class as this object's class.
      java.lang.String toString()
      Prints a query to a string.
      abstract java.lang.String toString​(java.lang.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
    • Field Detail

      • CLASS_NAME_HASH

        private final int CLASS_NAME_HASH
    • Constructor Detail

      • Query

        public Query()
    • Method Detail

      • toString

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

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

        public Weight createWeight​(IndexSearcher searcher,
                                   ScoreMode scoreMode,
                                   float boost)
                            throws java.io.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:
        java.io.IOException
      • rewrite

        public Query rewrite​(IndexReader reader)
                      throws java.io.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.

        Throws:
        java.io.IOException
        See Also:
        IndexSearcher.rewrite(Query)
      • 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​(java.lang.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 that other instance. Utility methods are provided for certain repetitive code.

        Overrides:
        equals in class java.lang.Object
        See Also:
        sameClassAs(Object), classHash()
      • 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 java.lang.Object
        See Also:
        equals(Object)
      • sameClassAs

        protected final boolean sameClassAs​(java.lang.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.