JoinDocFreqValueSource (Lucene 9.2.0 queries API)

java.lang.Object
- org.apache.lucene.queries.function.ValueSource
- - org.apache.lucene.queries.function.valuesource.FieldCacheSource
  - - org.apache.lucene.queries.function.valuesource.JoinDocFreqValueSource

```
public class JoinDocFreqValueSource
extends FieldCacheSource
```
Use a field value and find the Document Frequency within another field.

Since:

solr 4.0

Field Summary

Fields
Modifier and Type Field Description

static String NAME

protected String qfield
- Fields inherited from class org.apache.lucene.queries.function.valuesource.FieldCacheSource
  field

Constructor Summary

Constructors
Constructor Description

JoinDocFreqValueSource(String field, String qfield)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`String`	`description()`	description of field, used in explain()
`boolean`	`equals(Object o)`
`FunctionValues`	`getValues(Map<Object,Object> context, LeafReaderContext readerContext)`	Gets the values for this reader and the context that was previously passed to createWeight().
`int`	`hashCode()`

Methods inherited from class org.apache.lucene.queries.function.valuesource.FieldCacheSource
getField

Methods inherited from class org.apache.lucene.queries.function.ValueSource
asDoubleValuesSource, asLongValuesSource, createWeight, fromDoubleValuesSource, getSortField, newContext, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - NAME
```
public static final String NAME
```
    See Also:
    
    Constant Field Values
  - qfield
```
protected final String qfield
```
- Constructor Detail
  - JoinDocFreqValueSource
```
public JoinDocFreqValueSource(String field,
                              String qfield)
```
- Method Detail
  - description
```
public String description()
```
    Description copied from class: ValueSource
    
    description of field, used in explain()
    
    Overrides:
    
    description in class FieldCacheSource
  - getValues
```
public FunctionValues getValues(Map<Object,Object> context,
                                LeafReaderContext readerContext)
                         throws IOException
```
    Description copied from class: ValueSource
    
    Gets the values for this reader and the context that was previously passed to createWeight(). The values must be consumed in a forward docID manner, and you must call this method again to iterate through the values again.
    
    Specified by:
    
    getValues in class ValueSource
    
    Throws:
    
    IOException
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class FieldCacheSource
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class FieldCacheSource