core/org.gnit.lucenekmp.search/FuzzyQuery

FuzzyQuery

class FuzzyQuery(term: Term, maxEdits: Int = defaultMaxEdits, prefixLength: Int = defaultPrefixLength, maxExpansions: Int = defaultMaxExpansions, transpositions: Boolean = defaultTranspositions, rewriteMethod: MultiTermQuery.RewriteMethod = defaultRewriteMethod(maxExpansions)) : MultiTermQuery

Implements the fuzzy search query. The similarity measurement is based on the Damerau-Levenshtein (optimal string alignment) algorithm, though you can explicitly choose classic Levenshtein by passing false to the transpositions parameter.

This query uses MultiTermQuery.TopTermsBlendedFreqScoringRewrite as default. So terms will be collected and scored according to their edit distance. Only the top terms are used for building the BooleanQuery. It is not recommended to change the rewrite mode for fuzzy queries.

At most, this query will match terms up to {@value

LevenshteinAutomata#MAXIMUM_SUPPORTED_DISTANCE} edits. Higher distances (especially with transpositions enabled), are generally not useful and will match a significant amount of the term dictionary. If you really want this, consider using an n-gram indexing technique (such as the SpellChecker in the {@docRoot}/../suggest/overview-summary.html) instead.

NOTE: terms of length 1 or 2 will sometimes not match because of how the scaled distance between two terms is computed. For a term to match, the edit distance between the terms must be less than the minimum length term (either the input term, or the candidate term). For example, FuzzyQuery on term "abcd" with maxEdits=2 will not match an indexed term "ab", and FuzzyQuery on term "a" with maxEdits=2 will not match an indexed term "abc".

Constructors

FuzzyQuery

constructor(term: Term, maxEdits: Int = defaultMaxEdits, prefixLength: Int = defaultPrefixLength, maxExpansions: Int = defaultMaxExpansions, transpositions: Boolean = defaultTranspositions, rewriteMethod: MultiTermQuery.RewriteMethod = defaultRewriteMethod(maxExpansions))

Types

Companion

object Companion

Properties

automata

val automata: CompiledAutomaton

field

open val field: String

Returns the field name for this query

maxEdits

val maxEdits: Int

prefixLength

val prefixLength: Int

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.

rewriteMethod

val rewriteMethod: MultiTermQuery.RewriteMethod

termsCount

open val termsCount: Long

transpositions

val transpositions: Boolean

Returns true if transpositions should be treated as a primitive edit operation. If this is false, comparisons will implement the classic Levenshtein algorithm.

Functions

createWeight

open fun createWeight(searcher: IndexSearcher, scoreMode: ScoreMode, boost: Float): Weight

Expert: Constructs an appropriate Weight implementation for this query.

equals

open operator override fun equals(obj: Any?): Boolean

Override and implement query instance equivalence properly in a subclass. This is required so that QueryCache works properly.

getTerm

fun getTerm(): Term

Returns the pattern term.

getTermsEnum

fun getTermsEnum(terms: Terms): TermsEnum

Constructs an enumeration that expands the pattern term. This method should only be called if the field exists (ie, implementations can assume the field does exist). This method never returns null. The returned TermsEnum is positioned to the first matching term.

hashCode

open override fun hashCode(): Int

Override and implement query hash code properly in a subclass. This is required so that [ ] works properly.

rewrite

open override fun rewrite(indexSearcher: IndexSearcher): Query

To rewrite to a simpler form, instead return a simpler enum from .getTermsEnum. For example, to rewrite to a single term, return a SingleTermsEnum

toString

open override fun toString(field: String?): String

Prints a query to a string, with field assumed to be the default field and omitted.

open override fun toString(): String

Prints a query to a string.

visit

open override fun visit(visitor: QueryVisitor)

Recurse through the query tree, visiting any child queries.