org.apache.lucene.search
Class FuzzyLikeThisQuery
java.lang.Object
org.apache.lucene.search.Query
org.apache.lucene.search.FuzzyLikeThisQuery
- All Implemented Interfaces:
- Serializable, Cloneable
public class FuzzyLikeThisQuery
- extends org.apache.lucene.search.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.
- See Also:
- Serialized Form
Constructor Summary |
FuzzyLikeThisQuery(int maxNumTerms,
org.apache.lucene.analysis.Analyzer analyzer)
|
Methods inherited from class org.apache.lucene.search.Query |
clone, combine, createWeight, extractTerms, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight |
FuzzyLikeThisQuery
public FuzzyLikeThisQuery(int maxNumTerms,
org.apache.lucene.analysis.Analyzer analyzer)
- Parameters:
maxNumTerms
- The total number of terms clauses that will appear once rewritten as a BooleanQueryanalyzer
-
hashCode
public int hashCode()
- Overrides:
hashCode
in class org.apache.lucene.search.Query
equals
public boolean equals(Object obj)
- Overrides:
equals
in class org.apache.lucene.search.Query
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 parsedfieldName
- minSimilarity
- The minimum similarity of the term variants (see FuzzyTermEnum)prefixLength
- Length of required common prefix on variant terms (see FuzzyTermEnum)
rewrite
public org.apache.lucene.search.Query rewrite(org.apache.lucene.index.IndexReader reader)
throws IOException
- Overrides:
rewrite
in class org.apache.lucene.search.Query
- Throws:
IOException
toString
public String toString(String field)
- Specified by:
toString
in class org.apache.lucene.search.Query
isIgnoreTF
public boolean isIgnoreTF()
setIgnoreTF
public void setIgnoreTF(boolean ignoreTF)
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