Package org.apache.lucene.search.highlight

# Class QueryTermExtractor

java.lang.Object
org.apache.lucene.search.highlight.QueryTermExtractor

public final class QueryTermExtractor extends Object
Utility class used to extract the terms used in a query, plus any weights. This class will not find terms for MultiTermQuery, TermRangeQuery and PrefixQuery classes so the caller must pass a rewritten query (see Query.rewrite) to obtain a list of expanded terms.

## Constructor Summary

Constructors
Constructor
Description
`QueryTermExtractor()`

## Method Summary

Modifier and Type
Method
Description
`static final WeightedTerm[]`
`getIdfWeightedTerms(Query query, IndexReader reader, String fieldName)`
Extracts all terms texts of a given Query into an array of WeightedTerms
`static final WeightedTerm[]`
`getTerms(Query query)`
Extracts all terms texts of a given Query into an array of WeightedTerms
`static final WeightedTerm[]`
`getTerms(Query query, boolean prohibited)`
Extracts all terms texts of a given Query into an array of WeightedTerms
`static WeightedTerm[]`
`getTerms(Query query, boolean prohibited, String fieldName)`
Extracts all terms texts of a given Query into an array of WeightedTerms

### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Constructor Details

### QueryTermExtractor

public QueryTermExtractor()

## Method Details

### getTerms

public static final WeightedTerm[] getTerms(Query query)
Extracts all terms texts of a given Query into an array of WeightedTerms

Parameters:
  `query` - Query to extract term texts from
Returns:
  an array of the terms used in a query, plus their weights.

### getIdfWeightedTerms

public static final WeightedTerm[] getIdfWeightedTerms(Query query, IndexReader reader, String fieldName)
Extracts all terms texts of a given Query into an array of WeightedTerms

Parameters:
  `query` - Query to extract term texts from
  `reader` - used to compute IDF which can be used to a) score selected fragments better b) use graded highlights eg changing intensity of font color
  `fieldName` - the field on which Inverse Document Frequency (IDF) calculations are based
Returns:
  an array of the terms used in a query, plus their weights.

### getTerms

public static WeightedTerm[] getTerms(Query query, boolean prohibited, String fieldName)
Extracts all terms texts of a given Query into an array of WeightedTerms

Parameters:
  `query` - Query to extract term texts from
  `prohibited` - `true` to extract "prohibited" terms, too
  `fieldName` - The fieldName used to filter query terms
Returns:
  an array of the terms used in a query, plus their weights.

### getTerms

public static final WeightedTerm[] getTerms(Query query, boolean prohibited)
Extracts all terms texts of a given Query into an array of WeightedTerms

Parameters:
  `query` - Query to extract term texts from
  `prohibited` - `true` to extract "prohibited" terms, too
Returns:
  an array of the terms used in a query, plus their weights.