Class ExtremumOperator<T extends Comparable<T>>

java.lang.Object

tools.refinery.interpreter.matchers.aggregators.ExtremumOperator<T>

All Implemented Interfaces:

IMultisetAggregationOperator<T, SortedMap<T,Integer>, T>

public class ExtremumOperator<T extends Comparable<T>>
extends Object
implements IMultisetAggregationOperator<T, SortedMap<T,Integer>, 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	Description
static enum	ExtremumOperator.Extreme

Method Summary

Modifier and Type	Method	Description
T	aggregateStream(Stream<T> stream)	Calculates the aggregate results from a given stream of values; all values are considered as inserted
SortedMap<T,Integer>	clone(SortedMap<T,Integer> original)	Clones the given accumulator (with all its internal contents).
SortedMap<T,Integer>	createNeutral()
T	getAggregate(SortedMap<T,Integer> result)
static <T extends Comparable<T>> ExtremumOperator<T>	getMax()
static <T extends Comparable<T>> ExtremumOperator<T>	getMin()
String	getName()	A name or identifier of the operator.
String	getShortDescription()	A textual description of the operator.
boolean	isNeutral(SortedMap<T,Integer> result)
SortedMap<T,Integer>	update(SortedMap<T,Integer> oldResult, T updateValue, boolean isInsertion)

Methods inherited from class Object

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

Methods inherited from interface IMultisetAggregationOperator

combine, contains, prettyPrint

Method Details

getMin

public static <T extends Comparable<T>>
ExtremumOperator<T> getMin()

getMax

public static <T extends Comparable<T>>
ExtremumOperator<T> getMax()

getShortDescription

public String getShortDescription()

Description copied from interface: IMultisetAggregationOperator

A textual description of the operator.

Specified by:

getShortDescription in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

getName

public String getName()

Description copied from interface: IMultisetAggregationOperator

A name or identifier of the operator.

Specified by:

getName in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

createNeutral

public SortedMap<T,Integer> createNeutral()

Specified by:

createNeutral in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

Returns:

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

Since:

2.0

isNeutral

public boolean isNeutral(SortedMap<T,Integer> result)

Specified by:

isNeutral in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

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.

Since:

2.0

update

public SortedMap<T,Integer> update(SortedMap<T,Integer> oldResult,
 T updateValue,
 boolean isInsertion)

Specified by:

update in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

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)

Since:

2.0

getAggregate

public T getAggregate(SortedMap<T,Integer> result)

Specified by:

getAggregate in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

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).

Since:

2.0

aggregateStream

public T aggregateStream(Stream<T> stream)

Description copied from interface: IMultisetAggregationOperator

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

Specified by:

aggregateStream in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

Returns:

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

Since:

2.0

clone

public SortedMap<T,Integer> clone(SortedMap<T,Integer> original)

Description copied from interface: IMultisetAggregationOperator

Clones the given accumulator (with all its internal contents).

Specified by:

clone in interface IMultisetAggregationOperator<T extends Comparable<T>, SortedMap<T extends Comparable<T>, Integer>, T extends Comparable<T>>

Since:

2.4