Implements the fuzzy search query. The similarity measurement is based on the Levenshtein (edit distance) algorithm. More...

#include <FuzzyQuery.h>

Inheritance diagram for Lucene::FuzzyQuery:

Public Member Functions
	FuzzyQuery (const TermPtr &term, double minimumSimilarity, int32_t prefixLength)
	Create a new FuzzyQuery that will match terms with a similarity of at least minimumSimilarity to term. If a prefixLength > 0 is specified, a common prefix of that length is also required.
	FuzzyQuery (const TermPtr &term, double minimumSimilarity)
	FuzzyQuery (const TermPtr &term)
virtual	~FuzzyQuery ()
virtual String	getClassName ()
boost::shared_ptr< FuzzyQuery >	shared_from_this ()
double	getMinSimilarity ()
	Returns the minimum similarity that is required for this query to match.
int32_t	getPrefixLength ()
	Returns the non-fuzzy prefix length. This is the number of characters at the start of a term that must be identical (not fuzzy) to the query term if the query is to match that term.
TermPtr	getTerm ()
	Returns the pattern term.
virtual void	setRewriteMethod (const RewriteMethodPtr &method)
	Sets the rewrite method to be used when executing the query. You can use one of the four core methods, or implement your own subclass of `RewriteMethod`.
virtual QueryPtr	rewrite (const IndexReaderPtr &reader)
	Called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
virtual LuceneObjectPtr	clone (const LuceneObjectPtr &other=LuceneObjectPtr())
	Returns a clone of this query.
virtual String	toString (const String &field)
	Prints a query to a string, with field assumed to be the default field and omitted.
virtual int32_t	hashCode ()
	Return hash code for this object.
virtual bool	equals (const LuceneObjectPtr &other)
	Return whether two objects are equal.
Public Member Functions inherited from Lucene::MultiTermQuery
	MultiTermQuery ()
virtual	~MultiTermQuery ()
boost::shared_ptr< MultiTermQuery >	shared_from_this ()
int32_t	getTotalNumberOfTerms ()
	Return the number of unique terms visited during execution of the query. If there are many of them, you may consider using another query type or optimize your total term count in index.
void	clearTotalNumberOfTerms ()
	Resets the counting of unique terms. Do this before executing the query/filter.
virtual RewriteMethodPtr	getRewriteMethod ()
Public Member Functions inherited from Lucene::Query
	Query ()
virtual	~Query ()
boost::shared_ptr< Query >	shared_from_this ()
virtual void	setBoost (double 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.
virtual double	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.
virtual String	toString ()
	Prints a query to a string.
virtual WeightPtr	createWeight (const SearcherPtr &searcher)
	Constructs an appropriate Weight implementation for this query. Only implemented by primitive queries, which re-write to themselves.
virtual WeightPtr	weight (const SearcherPtr &searcher)
	Constructs and initializes a Weight for a top-level query.
virtual QueryPtr	combine (Collection< QueryPtr > queries)
	Called when re-writing queries under MultiSearcher.
virtual void	extractTerms (SetTerm terms)
	Adds all terms occurring in this query to the terms set. Only works if this query is in its `rewritten` form.
virtual SimilarityPtr	getSimilarity (const SearcherPtr &searcher)
	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.
String	boostString ()
	Return given boost value as a string.
Public Member Functions inherited from Lucene::LuceneObject
virtual	~LuceneObject ()
virtual void	initialize ()
	Called directly after instantiation to create objects that depend on this object being fully constructed.
virtual int32_t	compareTo (const LuceneObjectPtr &other)
	Compare two objects.
Public Member Functions inherited from Lucene::LuceneSync
virtual	~LuceneSync ()
virtual SynchronizePtr	getSync ()
	Return this object synchronize lock.
virtual LuceneSignalPtr	getSignal ()
	Return this object signal.
virtual void	lock (int32_t timeout=0)
	Lock this object using an optional timeout.
virtual void	unlock ()
	Unlock this object.
virtual bool	holdsLock ()
	Returns true if this object is currently locked by current thread.
virtual void	wait (int32_t timeout=0)
	Wait for signal using an optional timeout.
virtual void	notifyAll ()
	Notify all threads waiting for signal.

Static Public Member Functions
static String	_getClassName ()
static double	defaultMinSimilarity ()
Static Public Member Functions inherited from Lucene::MultiTermQuery
static String	_getClassName ()
static RewriteMethodPtr	CONSTANT_SCORE_FILTER_REWRITE ()
	A rewrite method that first creates a private Filter, by visiting each term in sequence and marking all docs for that term. Matching documents are assigned a constant score equal to the query's boost.
static RewriteMethodPtr	SCORING_BOOLEAN_QUERY_REWRITE ()
	A rewrite method that first translates each term into `BooleanClause.Occur#SHOULD` clause in a BooleanQuery, and keeps the scores as computed by the query. Note that typically such scores are meaningless to the user, and require non-trivial CPU to compute, so it's almost always better to use `CONSTANT_SCORE_AUTO_REWRITE_DEFAULT` instead.
static RewriteMethodPtr	CONSTANT_SCORE_BOOLEAN_QUERY_REWRITE ()
	Like `SCORING_BOOLEAN_QUERY_REWRITE` except scores are not computed. Instead, each matching document receives a constant score equal to the query's boost.
static RewriteMethodPtr	CONSTANT_SCORE_AUTO_REWRITE_DEFAULT ()
	Read-only default instance of `ConstantScoreAutoRewrite`, with `ConstantScoreAutoRewrite#setTermCountCutoff` set to `ConstantScoreAutoRewrite#DEFAULT_TERM_COUNT_CUTOFF` and `ConstantScoreAutoRewrite#setDocCountPercent` set to `ConstantScoreAutoRewrite#DEFAULT_DOC_COUNT_PERCENT`. Note that you cannot alter the configuration of this instance; you'll need to create a private instance instead.
Static Public Member Functions inherited from Lucene::Query
static String	_getClassName ()
static QueryPtr	mergeBooleanQueries (Collection< BooleanQueryPtr > queries)
	Merges the clauses of a set of BooleanQuery's into a single BooleanQuery.

Static Public Attributes
static const int32_t	defaultPrefixLength

Protected Member Functions
void	ConstructQuery (const TermPtr &term, double minimumSimilarity, int32_t prefixLength)
virtual FilteredTermEnumPtr	getEnum (const IndexReaderPtr &reader)
	Construct the enumeration to be used, expanding the pattern term.
Protected Member Functions inherited from Lucene::MultiTermQuery
void	incTotalNumberOfTerms (int32_t inc)
Protected Member Functions inherited from Lucene::LuceneObject
	LuceneObject ()

Protected Attributes
double	minimumSimilarity
int32_t	prefixLength
bool	termLongEnough
TermPtr	term
Protected Attributes inherited from Lucene::MultiTermQuery
RewriteMethodPtr	rewriteMethod
int32_t	numberOfTerms
Protected Attributes inherited from Lucene::Query
double	boost
Protected Attributes inherited from Lucene::LuceneSync
SynchronizePtr	objectLock
LuceneSignalPtr	objectSignal

Detailed Description

Implements the fuzzy search query. The similarity measurement is based on the Levenshtein (edit distance) algorithm.

Warning: this query is not very scalable with its default prefix length of 0 - in this case, every term will be enumerated and cause an edit score calculation.

Constructor & Destructor Documentation

◆ FuzzyQuery() [1/3]

Lucene::FuzzyQuery::FuzzyQuery	(	const TermPtr &	term,
		double	minimumSimilarity,
		int32_t	prefixLength )

Create a new FuzzyQuery that will match terms with a similarity of at least minimumSimilarity to term. If a prefixLength > 0 is specified, a common prefix of that length is also required.

Parameters

term	The term to search for
minimumSimilarity	A value between 0 and 1 to set the required similarity between the query term and the matching terms. For example, for a minimumSimilarity of 0.5 a term of the same length as the query term is considered similar to the query term if the edit distance between both terms is less than length(term) * 0.5
prefixLength	Length of common (non-fuzzy) prefix

References minimumSimilarity, prefixLength, and term.

Referenced by _getClassName().

◆ FuzzyQuery() [2/3]

Lucene::FuzzyQuery::FuzzyQuery	(	const TermPtr &	term,
		double	minimumSimilarity )

References minimumSimilarity, and term.

◆ FuzzyQuery() [3/3]

Lucene::FuzzyQuery::FuzzyQuery ( const TermPtr & term )

References term.

◆ ~FuzzyQuery()

virtual Lucene::FuzzyQuery::~FuzzyQuery ( )

virtual

Member Function Documentation

◆ _getClassName()

String Lucene::FuzzyQuery::_getClassName ( )

inlinestatic

References FuzzyQuery().

◆ clone()

virtual LuceneObjectPtr Lucene::FuzzyQuery::clone ( const LuceneObjectPtr & other = LuceneObjectPtr() )

virtual

Returns a clone of this query.

Reimplemented from Lucene::MultiTermQuery.

◆ ConstructQuery()

void Lucene::FuzzyQuery::ConstructQuery	(	const TermPtr &	term,
		double	minimumSimilarity,
		int32_t	prefixLength )

protected

References minimumSimilarity, prefixLength, and term.

◆ defaultMinSimilarity()

double Lucene::FuzzyQuery::defaultMinSimilarity ( )

static

◆ equals()

virtual bool Lucene::FuzzyQuery::equals ( const LuceneObjectPtr & other )

virtual

Return whether two objects are equal.

Reimplemented from Lucene::MultiTermQuery.

◆ getClassName()

virtual String Lucene::FuzzyQuery::getClassName ( )

inlinevirtual

Reimplemented from Lucene::MultiTermQuery.

◆ getEnum()

virtual FilteredTermEnumPtr Lucene::FuzzyQuery::getEnum ( const IndexReaderPtr & reader )

protectedvirtual

Construct the enumeration to be used, expanding the pattern term.

Implements Lucene::MultiTermQuery.

◆ getMinSimilarity()

double Lucene::FuzzyQuery::getMinSimilarity ( )

Returns the minimum similarity that is required for this query to match.

Returns: float value between 0.0 and 1.0

◆ getPrefixLength()

int32_t Lucene::FuzzyQuery::getPrefixLength ( )

Returns the non-fuzzy prefix length. This is the number of characters at the start of a term that must be identical (not fuzzy) to the query term if the query is to match that term.

◆ getTerm()

TermPtr Lucene::FuzzyQuery::getTerm ( )

Returns the pattern term.

◆ hashCode()

virtual int32_t Lucene::FuzzyQuery::hashCode ( )

virtual

Return hash code for this object.

Reimplemented from Lucene::MultiTermQuery.

◆ rewrite()

virtual QueryPtr Lucene::FuzzyQuery::rewrite ( const IndexReaderPtr & reader )

virtual

Called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Reimplemented from Lucene::MultiTermQuery.

◆ setRewriteMethod()

virtual void Lucene::FuzzyQuery::setRewriteMethod ( const RewriteMethodPtr & method )

virtual

Sets the rewrite method to be used when executing the query. You can use one of the four core methods, or implement your own subclass of RewriteMethod.

Reimplemented from Lucene::MultiTermQuery.

◆ shared_from_this()

boost::shared_ptr< FuzzyQuery > Lucene::FuzzyQuery::shared_from_this ( )

inline

◆ toString()

virtual String Lucene::FuzzyQuery::toString ( const String & field )

virtual

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 (eg. span queries) don't have a representation that can be parsed by QueryParser.

Reimplemented from Lucene::Query.

Field Documentation

◆ defaultPrefixLength

const int32_t Lucene::FuzzyQuery::defaultPrefixLength

static

◆ minimumSimilarity

double Lucene::FuzzyQuery::minimumSimilarity

protected

Referenced by ConstructQuery(), FuzzyQuery(), and FuzzyQuery().

◆ prefixLength

int32_t Lucene::FuzzyQuery::prefixLength

protected

Referenced by ConstructQuery(), and FuzzyQuery().

◆ term

TermPtr Lucene::FuzzyQuery::term

protected

Referenced by ConstructQuery(), FuzzyQuery(), FuzzyQuery(), and FuzzyQuery().

◆ termLongEnough

bool Lucene::FuzzyQuery::termLongEnough

protected

The documentation for this class was generated from the following file:

FuzzyQuery.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ FuzzyQuery() [1/3]

◆ FuzzyQuery() [2/3]

◆ FuzzyQuery() [3/3]

◆ ~FuzzyQuery()

Member Function Documentation

◆ _getClassName()

◆ clone()

◆ ConstructQuery()

◆ defaultMinSimilarity()

◆ equals()

◆ getClassName()

◆ getEnum()

◆ getMinSimilarity()

◆ getPrefixLength()

◆ getTerm()

◆ hashCode()

◆ rewrite()

◆ setRewriteMethod()

◆ shared_from_this()

◆ toString()

Field Documentation

◆ defaultPrefixLength

◆ minimumSimilarity

◆ prefixLength

◆ term

◆ termLongEnough