Class DoubleSumOperator

java.lang.Object

tools.refinery.interpreter.matchers.psystem.aggregations.AbstractMemorylessAggregationOperator<Double,Double>

tools.refinery.interpreter.matchers.aggregators.DoubleSumOperator

All Implemented Interfaces:

IMultisetAggregationOperator<Double,Double,Double>

public class DoubleSumOperator
extends AbstractMemorylessAggregationOperator<Double,Double>

Incrementally computes the sum of java.lang.Double values

Since:

1.4

Field Summary

Fields

Modifier and Type	Field	Description
static final DoubleSumOperator	INSTANCE

Method Summary

Modifier and Type	Method	Description
Double	aggregateStream(Stream<Double> stream)	Calculates the aggregate results from a given stream of values; all values are considered as inserted
Double	createNeutral()
String	getName()	A name or identifier of the operator.
String	getShortDescription()	A textual description of the operator.
boolean	isNeutral(Double result)
Double	update(Double oldResult, Double updateValue, boolean isInsertion)

Methods inherited from class AbstractMemorylessAggregationOperator

clone, getAggregate

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface IMultisetAggregationOperator

combine, contains, prettyPrint

Field Details

INSTANCE

public static final DoubleSumOperator INSTANCE

Method Details

getShortDescription

public String getShortDescription()

Description copied from interface: IMultisetAggregationOperator

A textual description of the operator.

getName

public String getName()

Description copied from interface: IMultisetAggregationOperator

A name or identifier of the operator.

createNeutral

public Double createNeutral()

Returns:

the neutral element, i.e. the interim result of aggregating an empty multiset.

isNeutral

public boolean isNeutral(Double result)

Returns:

true if the interim result is equivalent to the neutral element, as if there are no values in the multiset. Must return true if the multiset is empty.

update

public Double update(Double oldResult,
 Double updateValue,
 boolean isInsertion)

Returns:

an updated intermediate result, changed to reflect that a given object was added to / removed from the multiset (as indicated by the parameter isInsertion)

aggregateStream

public Double aggregateStream(Stream<Double> stream)

Description copied from interface: IMultisetAggregationOperator

Calculates the aggregate results from a given stream of values; all values are considered as inserted

Returns:

the aggregate result, or null if no result can be calculated (e.g. because of an empty stream)

Since:

2.0