Module org.apache.lucene.classification

Package org.apache.lucene.classification.utils

Class NearestFuzzyQuery

java.lang.Object

org.apache.lucene.search.Query

org.apache.lucene.classification.utils.NearestFuzzyQuery

public class NearestFuzzyQuery
extends Query

Simplification of FuzzyLikeThisQuery, to be used in the context of KNN classification.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	NearestFuzzyQuery.FieldVals
private static class	NearestFuzzyQuery.ScoreTerm
private static class	NearestFuzzyQuery.ScoreTermQueue

Field Summary

Fields

Modifier and Type	Field	Description
private final Analyzer	analyzer
private final ArrayList<NearestFuzzyQuery.FieldVals>	fieldVals
private static final int	MAX_NUM_TERMS
private static final int	MAX_VARIANTS_PER_TERM
private static final float	MIN_SIMILARITY
private static final int	PREFIX_LENGTH

Constructor Summary

Constructors

Constructor	Description
NearestFuzzyQuery(Analyzer analyzer)	Default constructor

Method Summary

Modifier and Type	Method	Description
void	addTerms(String queryString, String fieldName)	Adds user input for "fuzzification"
private void	addTerms(IndexReader reader, NearestFuzzyQuery.FieldVals f, NearestFuzzyQuery.ScoreTermQueue q)
boolean	equals(Object other)	Override and implement query instance equivalence properly in a subclass.
private boolean	equalsTo(NearestFuzzyQuery other)
int	hashCode()	Override and implement query hash code properly in a subclass.
private float	idf(int docFreq, int docCount)
private Query	newTermQuery(IndexReader reader, Term term)
Query	rewrite(IndexSearcher indexSearcher)	Expert: called to re-write queries into primitive queries.
String	toString(String field)	Prints a query to a string, with field assumed to be the default field and omitted.
void	visit(QueryVisitor visitor)	Recurse through the query tree, visiting any child queries.

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

classHash, createWeight, rewrite, sameClassAs, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

fieldVals

private final ArrayList<NearestFuzzyQuery.FieldVals> fieldVals

analyzer

private final Analyzer analyzer

MAX_VARIANTS_PER_TERM

private static final int MAX_VARIANTS_PER_TERM

See Also:

• Constant Field Values

MIN_SIMILARITY

private static final float MIN_SIMILARITY

See Also:

• Constant Field Values

PREFIX_LENGTH

private static final int PREFIX_LENGTH

See Also:

• Constant Field Values

MAX_NUM_TERMS

private static final int MAX_NUM_TERMS

See Also:

• Constant Field Values

Constructor Details

NearestFuzzyQuery

public NearestFuzzyQuery(Analyzer analyzer)

Default constructor

Parameters:

analyzer - the analyzer used to process the query text

Method Details

addTerms

public void addTerms(String queryString,
 String fieldName)

Adds user input for "fuzzification"

Parameters:

queryString - The string which will be parsed by the analyzer and for which fuzzy variants will be parsed

addTerms

private void addTerms(IndexReader reader,
 NearestFuzzyQuery.FieldVals f,
 NearestFuzzyQuery.ScoreTermQueue q)
               throws IOException

Throws:

IOException

idf

private float idf(int docFreq,
 int docCount)

newTermQuery

private Query newTermQuery(IndexReader reader,
 Term term)
                    throws IOException

Throws:

IOException

rewrite

public Query rewrite(IndexSearcher indexSearcher)
              throws IOException

Description copied from class: Query

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

Callers are expected to call rewrite multiple times if necessary, until the rewritten query is the same as the original query.

The rewrite process may be able to make use of IndexSearcher's executor and be executed in parallel if the executor is provided.

However, if any of the intermediary queries do not satisfy the new API, parallel rewrite is not possible for any subsequent sub-queries. To take advantage of this API, the entire query tree must override this method.

Overrides:

rewrite in class Query

Throws:

IOException

See Also:

• IndexSearcher.rewrite(Query)

toString

public String toString(String field)

Description copied from class: Query

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

Specified by:

toString in class Query

hashCode

public int hashCode()

Description copied from class: Query

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

Specified by:

hashCode in class Query

See Also:

• Query.equals(Object)

equals

public boolean equals(Object other)

Description copied from class: Query

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

Typically a query will be equal to another only if it's an instance of the same class and its document-filtering properties are identical to those of the other instance. Utility methods are provided for certain repetitive code.

Specified by:

equals in class Query

See Also:

• Query.sameClassAs(Object)
• Query.classHash()

equalsTo

private boolean equalsTo(NearestFuzzyQuery other)

visit

public void visit(QueryVisitor visitor)

Description copied from class: Query

Recurse through the query tree, visiting any child queries.

Specified by:

visit in class Query

Parameters:

visitor - a QueryVisitor to be called by each query in the tree