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abstract public class: Query [javadoc | source]

All Implemented Interfaces:
    Cloneable, Serializable

The abstract base class for queries.

Instantiable subclasses are:

A parser for queries is contained in:

Method from Summary:
clone,   combine,   createWeight,   equals,   extractTerms,   getBoost,   getSimilarity,   hashCode,   mergeBooleanQueries,   rewrite,   setBoost,   toString,   toString,   weight
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from Detail:
 public Object clone() 
    Returns a clone of this query.
 public Query combine(Query[] queries) 
    Expert: called when re-writing queries under MultiSearcher. Create a single query suitable for use by all subsearchers (in 1-1 correspondence with queries). This is an optimization of the OR of all queries. We handle the common optimization cases of equal queries and overlapping clauses of boolean OR queries (as generated by MultiTermQuery.rewrite()). Be careful overriding this method as queries[0] determines which method will be called and is not necessarily of the same type as the other queries.
 public Weight createWeight(Searcher searcher) throws IOException 
    Expert: Constructs an appropriate Weight implementation for this query.

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

 public boolean equals(Object obj) 
 public  void extractTerms(Set<Term> terms) 
    Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its rewritten form.
 public float getBoost() 
    Gets the boost for this clause. Documents matching this clause will (in addition to the normal weightings) have their score multiplied by b. The boost is 1.0 by default.
 public Similarity getSimilarity(Searcher searcher) 
    Expert: Returns the Similarity implementation to be used for this query. Subclasses may override this method to specify their own Similarity implementation, perhaps one that delegates through that of the Searcher. By default the Searcher's Similarity implementation is returned.
 public int hashCode() 
 public static Query mergeBooleanQueries(BooleanQuery queries) 
    Expert: merges the clauses of a set of BooleanQuery's into a single BooleanQuery.

    A utility for use by #combine(Query[]) implementations.

 public Query rewrite(IndexReader reader) 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.
 public  void setBoost(float b) 
    Sets the boost for this query clause to b. Documents matching this clause will (in addition to the normal weightings) have their score multiplied by b.
 public String toString() 
    Prints a query to a string.
 abstract public String toString(String field)
    Prints a query to a string, with field assumed to be the default field and omitted.

    The representation used is one that is supposed to be readable by QueryParser . However, there are the following limitations:

    • If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash.
    • Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.
 public Weight weight(Searcher searcher) throws IOException 
    Expert: Constructs and initializes a Weight for a top-level query.