org.eclipse.viatra.query.runtime.matchers.aggregators

Class ExtremumOperator<T extends java.lang.Comparable<T>>

java.lang.Object

org.eclipse.viatra.query.runtime.matchers.psystem.aggregations.AbstractMultisetAggregationOperator<T,com.google.common.collect.SortedMultiset<T>,T>

org.eclipse.viatra.query.runtime.matchers.aggregators.ExtremumOperator<T>

All Implemented Interfaces:

IMultisetAggregationOperator<T,com.google.common.collect.SortedMultiset<T>,T>

public class ExtremumOperator<T extends java.lang.Comparable<T>>
extends AbstractMultisetAggregationOperator<T,com.google.common.collect.SortedMultiset<T>,T>

Incrementally computes the minimum or maximum of java.lang.Comparable values, using the default comparison

Since:

1.4

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ExtremumOperator.Extreme

Method Summary

Modifier and Type	Method and Description
com.google.common.collect.SortedMultiset<T>	createNeutral()
T	getAggregate(com.google.common.collect.SortedMultiset<T> result)
static <T extends java.lang.Comparable<T>> ExtremumOperator<T>	getMax()
static <T extends java.lang.Comparable<T>> ExtremumOperator<T>	getMin()
java.lang.String	getName() A name or identifier of the operator.
java.lang.String	getShortDescription() A textual description of the operator.
boolean	isNeutral(com.google.common.collect.SortedMultiset<T> result)
com.google.common.collect.SortedMultiset<T>	update(com.google.common.collect.SortedMultiset<T> oldResult, T updateValue, boolean isInsertion)

Methods inherited from class java.lang.Object

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

Method Detail

getMin

public static <T extends java.lang.Comparable<T>> ExtremumOperator<T> getMin()

getMax

public static <T extends java.lang.Comparable<T>> ExtremumOperator<T> getMax()

getShortDescription

public java.lang.String getShortDescription()

Description copied from interface: IMultisetAggregationOperator

A textual description of the operator.

getName

public java.lang.String getName()

Description copied from interface: IMultisetAggregationOperator

A name or identifier of the operator.

createNeutral

public com.google.common.collect.SortedMultiset<T> createNeutral()

Returns:

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

isNeutral

public boolean isNeutral(com.google.common.collect.SortedMultiset<T> 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 com.google.common.collect.SortedMultiset<T> update(com.google.common.collect.SortedMultiset<T> oldResult,
                                                          T 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)

getAggregate

public T getAggregate(com.google.common.collect.SortedMultiset<T> result)

Returns:

the aggregate result obtained from the given intermediate result. May be null to indicate that the current multiset cannot be aggregated (e.g. 0 elements have no minimum).