Class FuzzyLikeThisQuery
- java.lang.Object
-
- org.apache.lucene.search.Query
-
- org.apache.lucene.sandbox.queries.FuzzyLikeThisQuery
-
public class FuzzyLikeThisQuery extends Query
Fuzzifies ALL terms provided as strings and then picks the best n differentiating terms. In effect this mixes the behaviour of FuzzyQuery and MoreLikeThis but with special consideration of fuzzy scoring factors. This generally produces good results for queries where users may provide details in a number of fields and have no knowledge of boolean query syntax and also want a degree of fuzzy matching and a fast query. For each source term the fuzzy variants are held in a BooleanQuery with no coord factor (because we are not looking for matches on multiple variants in any one doc). Additionally, a specialized TermQuery is used for variants and does not use that variant term's IDF because this would favour rarer terms eg misspellings. Instead, all variants use the same IDF ranking (the one for the source query term) and this is factored into the variant's boost. If the source query term does not exist in the index the average IDF of the variants is used.
-
-
Constructor Summary
Constructors Constructor Description FuzzyLikeThisQuery(int maxNumTerms, Analyzer analyzer)
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addTerms(String queryString, String fieldName, float minSimilarity, int prefixLength)
Adds user input for "fuzzification"boolean
equals(Object other)
int
hashCode()
boolean
isIgnoreTF()
Query
rewrite(IndexReader reader)
void
setIgnoreTF(boolean ignoreTF)
String
toString(String field)
void
visit(QueryVisitor visitor)
-
Methods inherited from class org.apache.lucene.search.Query
classHash, createWeight, sameClassAs, toString
-
-
-
-
Constructor Detail
-
FuzzyLikeThisQuery
public FuzzyLikeThisQuery(int maxNumTerms, Analyzer analyzer)
- Parameters:
maxNumTerms
- The total number of terms clauses that will appear once rewritten as a BooleanQuery
-
-
Method Detail
-
addTerms
public void addTerms(String queryString, String fieldName, float minSimilarity, int prefixLength)
Adds user input for "fuzzification"- Parameters:
queryString
- The string which will be parsed by the analyzer and for which fuzzy variants will be parsedminSimilarity
- The minimum similarity of the term variants; must be 0, 1 or 2 (see FuzzyTermsEnum)prefixLength
- Length of required common prefix on variant terms (see FuzzyTermsEnum)
-
visit
public void visit(QueryVisitor visitor)
-
rewrite
public Query rewrite(IndexReader reader) throws IOException
- Overrides:
rewrite
in classQuery
- Throws:
IOException
-
isIgnoreTF
public boolean isIgnoreTF()
-
setIgnoreTF
public void setIgnoreTF(boolean ignoreTF)
-
-