Package org.apache.qpid.server.query.engine.parsing.factory

Class CollectorFactory

java.lang.Object

org.apache.qpid.server.query.engine.parsing.factory.CollectorFactory

public final class CollectorFactory
extends Object

Factory creating collectors for aggregation functions

Method Summary

Modifier and Type	Method	Description
static <T,A,R> Function<Expression<T,R>,Collector<T,A,R>>	collector(CollectorType collectorType)	Creates collector from collector type
static <T,A,R> Collector<T,A,R>	filtering(Predicate<? super T> filter, Collector<T,A,R> collector)	Filtering collector

Methods inherited from class java.lang.Object

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

Method Detail

collector

public static <T,A,R> Function<Expression<T,R>,Collector<T,A,R>> collector(CollectorType collectorType)

Creates collector from collector type

Type Parameters:

T - Input parameter type

A - Accumulator type

R - Return parameter type

Parameters:

collectorType - Collector type

Returns:

Function creating collector

filtering

public static <T,A,R> Collector<T,A,R> filtering(Predicate<? super T> filter,
                                                                         Collector<T,A,R> collector)

Filtering collector

Type Parameters:

T - Input parameter type

A - Accumulator type

R - Return parameter type

Parameters:

filter - Predicate to filter

collector - Collector in chain

Returns:

Collector instance