AggNull (Apache Jena ARQ)

java.lang.Object
- org.apache.jena.sparql.expr.aggregate.AggregatorBase
- - org.apache.jena.sparql.expr.aggregate.AggNull

All Implemented Interfaces:

Aggregator
```
public class AggNull
extends AggregatorBase
```
The null aggregate (which can't be written in SPARQL) calculates nothing but does help remember the group key.

Constructor Summary

Constructors
Constructor Description

AggNull()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`Aggregator`	`copy(ExprList exprs)`
`static Accumulator`	`createAccNull()`
`Accumulator`	`createAccumulator()`	Create an accumulator for this aggregator
`boolean`	`equals(Aggregator other, boolean bySyntax)`	Consider this 'protected'
`Node`	`getValueEmpty()`	Value if there are no groups : return null for no result
`int`	`hashCode()`

Methods inherited from class org.apache.jena.sparql.expr.aggregate.AggregatorBase
asSparqlExpr, copyTransform, equals, getExprList, getName, getValue, key, toPrefixString, toString

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

- Constructor Detail
  - AggNull
```
public AggNull()
```
- Method Detail
  - copy
```
public Aggregator copy(ExprList exprs)
```
  - createAccumulator
```
public Accumulator createAccumulator()
```
    Description copied from interface: Aggregator
    
    Create an accumulator for this aggregator
    
    Specified by:
    
    createAccumulator in interface Aggregator
    
    Specified by:
    
    createAccumulator in class AggregatorBase
  - getValueEmpty
```
public Node getValueEmpty()
```
    Description copied from interface: Aggregator
    
    Value if there are no groups : return null for no result
    
    Specified by:
    
    getValueEmpty in interface Aggregator
    
    Specified by:
    
    getValueEmpty in class AggregatorBase
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface Aggregator
    
    Specified by:
    
    hashCode in class AggregatorBase
  - equals
```
public boolean equals(Aggregator other,
                      boolean bySyntax)
```
    Description copied from interface: Aggregator
    
    Consider this 'protected'
  - createAccNull
```
public static Accumulator createAccNull()
```