org.apache.lucene.search
Class FuzzyQuery

java.lang.Object
  org.apache.lucene.search.Query
      org.apache.lucene.search.MultiTermQuery
          org.apache.lucene.search.FuzzyQuery

All Implemented Interfaces:

Cloneable, Serializable

public final class FuzzyQuery

extends MultiTermQuery

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

See Also:

Serialized Form

Field Summary

static float

defaultMinSimilarity

Constructor Summary

FuzzyQuery(Term term)
Calls FuzzyQuery(term, 0.5f, 0).

FuzzyQuery(Term term, float minimumSimilarity)
Calls FuzzyQuery(term, minimumSimilarity, 0).

FuzzyQuery(Term term, float minimumSimilarity, int prefixLength)
Create a new FuzzyQuery that will match terms with a similarity of at least minimumSimilarity to term.

Method Summary

protected FilteredTermEnum	getEnum(IndexReader reader) Construct the enumeration to be used, expanding the pattern term.
float	getMinSimilarity() Returns the minimum similarity that is required for this query to match.
int	getPrefixLength() Returns the prefix length, i.e. 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.
String	toString(String field) Prints a user-readable version of this query.

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

combine, getTerm, rewrite

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

clone, createWeight, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

defaultMinSimilarity

public static final float defaultMinSimilarity

See Also:

Constant Field Values

Constructor Detail

FuzzyQuery

public FuzzyQuery(Term term,
                  float minimumSimilarity,
                  int prefixLength)
           throws IllegalArgumentException

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

Throws:

IllegalArgumentException - if minimumSimilarity is > 1 or < 0 or if prefixLength < 0 or > term.text().length().

FuzzyQuery

public FuzzyQuery(Term term,
                  float minimumSimilarity)
           throws IllegalArgumentException

Calls FuzzyQuery(term, minimumSimilarity, 0).

FuzzyQuery

public FuzzyQuery(Term term)

Calls FuzzyQuery(term, 0.5f, 0).

Method Detail

getMinSimilarity

public float getMinSimilarity()

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

Returns:

float value between 0.0 and 1.0

getPrefixLength

public int getPrefixLength()

Returns the prefix length, i.e. 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.

getEnum

protected FilteredTermEnum getEnum(IndexReader reader)
                            throws IOException

Description copied from class: MultiTermQuery

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

Specified by:

getEnum in class MultiTermQuery

Throws:

IOException

toString

public String toString(String field)

Description copied from class: MultiTermQuery

Prints a user-readable version of this query.

Overrides:

toString in class MultiTermQuery