Package org.apache.lucene.queries.function

# Class IndexReaderFunctions

java.lang.Object
org.apache.lucene.queries.function.IndexReaderFunctions

public final class IndexReaderFunctions extends Object
Class exposing static helper methods for generating DoubleValuesSource instances over some IndexReader statistics

## Method Summary

Modifier and Type
Method
Description
`static DoubleValuesSource`
`docCount(String field)`
Creates a constant value source returning the docCount for a given field
`static DoubleValuesSource`
`docFreq(Term term)`
Creates a constant value source returning the docFreq of a given term
`static DoubleValuesSource`
`maxDoc()`
Creates a constant value source returning the index's maxDoc
`static DoubleValuesSource`
`numDeletedDocs()`
Creates a constant value source returning the number of deleted docs in the index
`static DoubleValuesSource`
`numDocs()`
Creates a constant value source returning the index's numDocs
`static DoubleValuesSource`
`sumDocFreq(String field)`
Creates a constant value source returning the sumDocFreq for a given field
`static LongValuesSource`
`sumTotalTermFreq(String field)`
Creates a constant value source returning the sumTotalTermFreq for a field
`static DoubleValuesSource`
`termFreq(Term term)`
Creates a value source that returns the term freq of a given term for each document
`static DoubleValuesSource`
`totalTermFreq(Term term)`
Creates a constant value source returning the totalTermFreq for a given term

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

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

## Method Details

### docFreq

public static DoubleValuesSource docFreq(Term term)
Creates a constant value source returning the docFreq of a given term

See Also:
  - `IndexReader.docFreq(Term)`

### maxDoc

public static DoubleValuesSource maxDoc()
Creates a constant value source returning the index's maxDoc

See Also:
  - `IndexReader.maxDoc()`

### numDocs

public static DoubleValuesSource numDocs()
Creates a constant value source returning the index's numDocs

See Also:
  - `IndexReader.numDocs()`

### numDeletedDocs

public static DoubleValuesSource numDeletedDocs()
Creates a constant value source returning the number of deleted docs in the index

See Also:
  - `IndexReader.numDeletedDocs()`

### sumTotalTermFreq

public static LongValuesSource sumTotalTermFreq(String field)
Creates a constant value source returning the sumTotalTermFreq for a field

See Also:
  - `IndexReader.getSumTotalTermFreq(String)`

### termFreq

public static DoubleValuesSource termFreq(Term term)
Creates a value source that returns the term freq of a given term for each document

See Also:
  - `PostingsEnum.freq()`

### totalTermFreq

public static DoubleValuesSource totalTermFreq(Term term)
Creates a constant value source returning the totalTermFreq for a given term

See Also:
  - `IndexReader.totalTermFreq(Term)`

### sumDocFreq

public static DoubleValuesSource sumDocFreq(String field)
Creates a constant value source returning the sumDocFreq for a given field

See Also:
  - `IndexReader.getSumDocFreq(String)`

### docCount

public static DoubleValuesSource docCount(String field)
Creates a constant value source returning the docCount for a given field

See Also:
  - `IndexReader.getDocCount(String)`