Interface IRelationEvaluator

public interface IRelationEvaluator

Implementations of this interface take an arbitrary number of input relations with their contents and compute the tuples of a single output relation.

Since:

2.8

Method Summary

Modifier and Type	Method	Description
Set<Tuple>	evaluateRelation(List<Set<Tuple>> inputs)	The relation evaluator code.
List<Integer>	getInputArities()	For each input relation that this evaluator requires, this method returns the expected arities of the relations in order.
int	getOutputArity()	Returns the arity of the output relation that this evaluator computes.
String	getShortDescription()	A textual description of the evaluator.

Method Details

getShortDescription

String getShortDescription()

A textual description of the evaluator. Used only for debug purposes, but must not be null.

evaluateRelation

Set<Tuple> evaluateRelation(List<Set<Tuple>> inputs)
                     throws Exception

The relation evaluator code. For performance reasons, it is expected that the returned set is a mutable collection, and the caller must be allowed to actually perform mutations!

Throws:

Exception

getInputArities

List<Integer> getInputArities()

For each input relation that this evaluator requires, this method returns the expected arities of the relations in order.

getOutputArity

int getOutputArity()

Returns the arity of the output relation that this evaluator computes.