SingleFunction (Lucene 8.6.0 API)

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

Direct Known Subclasses:

SimpleFloatFunction
```
public abstract class SingleFunction
extends ValueSource
```
A function with a single argument

Field Summary

Fields
Modifier and Type Field Description

protected ValueSource source

Constructor Summary

Constructors
Constructor Description

SingleFunction(ValueSource source)

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`createWeight(Map context, IndexSearcher searcher)`	Implementations should propagate createWeight to sub-ValueSources which can optionally store weight info in the context.
`String`	`description()`	description of field, used in explain()
`boolean`	`equals(Object o)`
`int`	`hashCode()`
`protected abstract String`	`name()`

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

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

- Field Detail
  - source
```
protected final ValueSource source
```
- Constructor Detail
  - SingleFunction
```
public SingleFunction(ValueSource source)
```
- Method Detail
  - name
```
protected abstract String name()
```
  - description
```
public String description()
```
    Description copied from class: ValueSource
    
    description of field, used in explain()
    
    Specified by:
    
    description in class ValueSource
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in class ValueSource
  - equals
```
public boolean equals(Object o)
```
    Specified by:
    
    equals in class ValueSource
  - createWeight
```
public void createWeight(Map context,
                         IndexSearcher searcher)
                  throws IOException
```
    Description copied from class: ValueSource
    
    Implementations should propagate createWeight to sub-ValueSources which can optionally store weight info in the context. The context object will be passed to getValues() where this info can be retrieved.
    
    Overrides:
    
    createWeight in class ValueSource
    
    Throws:
    
    IOException