Package org.apache.lucene.search

Class RegexpQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.search.MultiTermQuery

org.apache.lucene.search.AutomatonQuery

org.apache.lucene.search.RegexpQuery

public class RegexpQuery
extends AutomatonQuery

A fast regular expression query based on the org.apache.lucene.util.automaton package.

• Comparisons are fast
• The term dictionary is enumerated in an intelligent way, to avoid comparisons. See AutomatonQuery for more details.

The supported syntax is documented in the RegExp class. Note this might be different than other regular expression implementations. For some alternatives with different syntax, look under the sandbox.

Note this query can be slow, as it needs to iterate over many terms. In order to prevent extremely slow RegexpQueries, a Regexp term should not start with the expression .*

See Also:

RegExp

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.search.MultiTermQuery

MultiTermQuery.RewriteMethod, MultiTermQuery.TopTermsBlendedFreqScoringRewrite, MultiTermQuery.TopTermsBoostOnlyBooleanQueryRewrite, MultiTermQuery.TopTermsScoringBooleanQueryRewrite

Field Summary

Fields inherited from class org.apache.lucene.search.AutomatonQuery

automaton, automatonIsBinary, compiled, term

Fields inherited from class org.apache.lucene.search.MultiTermQuery

CONSTANT_SCORE_BOOLEAN_REWRITE, CONSTANT_SCORE_REWRITE, field, rewriteMethod, SCORING_BOOLEAN_REWRITE

Constructor Summary

Constructors

Constructor	Description
RegexpQuery(Term term)	Constructs a query for terms matching term.
RegexpQuery(Term term, int flags)	Constructs a query for terms matching term.
RegexpQuery(Term term, int flags, int maxDeterminizedStates)	Constructs a query for terms matching term.
RegexpQuery(Term term, int flags, AutomatonProvider provider, int maxDeterminizedStates)	Constructs a query for terms matching term.

Method Summary

Modifier and Type	Method	Description
Term	getRegexp()	Returns the regexp of this query wrapped in a Term.
String	toString(String field)	Prints a user-readable version of this query.

Methods inherited from class org.apache.lucene.search.AutomatonQuery

equals, getAutomaton, getTermsEnum, hashCode, isAutomatonBinary

Methods inherited from class org.apache.lucene.search.MultiTermQuery

getField, getRewriteMethod, getTermsEnum, rewrite, setRewriteMethod

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

classHash, createWeight, sameClassAs, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

RegexpQuery

public RegexpQuery(Term term)

Constructs a query for terms matching term.

By default, all regular expression features are enabled.

Parameters:

term - regular expression.

RegexpQuery

public RegexpQuery(Term term,
                   int flags)

Constructs a query for terms matching term.

Parameters:

term - regular expression.

flags - optional RegExp features from RegExp

RegexpQuery

public RegexpQuery(Term term,
                   int flags,
                   int maxDeterminizedStates)

Constructs a query for terms matching term.

Parameters:

term - regular expression.

flags - optional RegExp features from RegExp

maxDeterminizedStates - maximum number of states that compiling the automaton for the regexp can result in. Set higher to allow more complex queries and lower to prevent memory exhaustion.

RegexpQuery

public RegexpQuery(Term term,
                   int flags,
                   AutomatonProvider provider,
                   int maxDeterminizedStates)

Constructs a query for terms matching term.

Parameters:

term - regular expression.

flags - optional RegExp features from RegExp

provider - custom AutomatonProvider for named automata

maxDeterminizedStates - maximum number of states that compiling the automaton for the regexp can result in. Set higher to allow more complex queries and lower to prevent memory exhaustion.

Method Detail

getRegexp

public Term getRegexp()

Returns the regexp of this query wrapped in a Term.

toString

public String toString(String field)

Prints a user-readable version of this query.

Overrides:

toString in class AutomatonQuery