com.hp.hpl.jena.sparql.expr.aggregate
Class AggNull
java.lang.Object
com.hp.hpl.jena.sparql.expr.aggregate.AggregatorBase
com.hp.hpl.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 nothering but does help remember the group key
AggNull
public AggNull()
copy
public Aggregator copy(Expr expr)
toString
public String toString()
- Specified by:
toString in class AggregatorBase
toPrefixString
public String toPrefixString()
- Specified by:
toPrefixString in interface Aggregator- Specified by:
toPrefixString in class AggregatorBase
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 com.hp.hpl.jena.graph.Node getValueEmpty()
- Description copied from interface:
Aggregator
- Value if there are no elements in any group : return null for no result
- Specified by:
getValueEmpty in interface Aggregator- Specified by:
getValueEmpty in class AggregatorBase
getExpr
public Expr getExpr()
- Description copied from interface:
Aggregator
- Get the expression - may be null (e.g COUNT(*)) ;
hashCode
public int hashCode()
- Specified by:
hashCode in interface Aggregator- Specified by:
hashCode in class AggregatorBase
equals
public boolean equals(Object other)
- Specified by:
equals in interface Aggregator- Specified by:
equals in class AggregatorBase
createAccNull
public static Accumulator createAccNull()
Licenced under the Apache License, Version 2.0