org.apache.flink.api.java.summarize.aggregation

Class ValueSummaryAggregator<VT extends Value,PT,R,A extends Aggregator<PT,R>>

java.lang.Object

org.apache.flink.api.java.summarize.aggregation.ValueSummaryAggregator<VT,PT,R,A>

Type Parameters:

VT - the "Value Type" to aggregate, e.g. DoubleValue, StringValue

PT - the "Primitive Type" that "Value Type" can be naturally converted to, e.g. DoubleValue converts to Double

R - the result type of the aggregation, e.g. NumericColumnSummary<Double>

A - the underlying primitive Aggregator that does the actual work, e.g. DoubleSummaryAggregator

All Implemented Interfaces:

Serializable, Aggregator<VT,R>

Direct Known Subclasses:

ValueSummaryAggregator.BooleanValueSummaryAggregator, ValueSummaryAggregator.DoubleValueSummaryAggregator, ValueSummaryAggregator.FloatValueSummaryAggregator, ValueSummaryAggregator.IntegerValueSummaryAggregator, ValueSummaryAggregator.LongValueSummaryAggregator, ValueSummaryAggregator.ShortValueSummaryAggregator, ValueSummaryAggregator.StringValueSummaryAggregator

@Internal
public abstract class ValueSummaryAggregator<VT extends Value,PT,R,A extends Aggregator<PT,R>>
extends Object
implements Aggregator<VT,R>

This is a generic Aggregator for Value types like StringValue, DoubleValue, etc. This class makes it easy to re-use the implementation of another aggregator.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ValueSummaryAggregator.BooleanValueSummaryAggregator A ValueSummaryAggregator for Boolean.
static class	ValueSummaryAggregator.DoubleValueSummaryAggregator A ValueSummaryAggregator for Double.
static class	ValueSummaryAggregator.FloatValueSummaryAggregator A ValueSummaryAggregator for Float.
static class	ValueSummaryAggregator.IntegerValueSummaryAggregator A ValueSummaryAggregator for Integer.
static class	ValueSummaryAggregator.LongValueSummaryAggregator A ValueSummaryAggregator for Long.
static class	ValueSummaryAggregator.ShortValueSummaryAggregator A ValueSummaryAggregator for Short.
static class	ValueSummaryAggregator.StringValueSummaryAggregator A ValueSummaryAggregator for String.

Constructor Summary

Constructors

Constructor and Description
ValueSummaryAggregator()

Method Summary

Modifier and Type	Method and Description
void	aggregate(VT value) Add a value to the current aggregation.
void	combine(Aggregator<VT,R> otherSameType) Combine two aggregations of the same type.
protected abstract PT	getValue(VT value) Get the value out of a value type.
protected abstract A	initPrimitiveAggregator() Initialize an aggregator that can be used for the underlying primitive in the Value type.
R	result() Provide the final result of the aggregation.

Methods inherited from class java.lang.Object

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

Constructor Detail

ValueSummaryAggregator

public ValueSummaryAggregator()

Method Detail

aggregate

public void aggregate(VT value)

Description copied from interface: Aggregator

Add a value to the current aggregation.

Specified by:

aggregate in interface Aggregator<VT extends Value,R>

combine

public void combine(Aggregator<VT,R> otherSameType)

Description copied from interface: Aggregator

Combine two aggregations of the same type.

(Implementations will need to do an unchecked cast).

Specified by:

combine in interface Aggregator<VT extends Value,R>

result

public R result()

Description copied from interface: Aggregator

Provide the final result of the aggregation.

Specified by:

result in interface Aggregator<VT extends Value,R>

initPrimitiveAggregator

protected abstract A initPrimitiveAggregator()

Initialize an aggregator that can be used for the underlying primitive in the Value type.

E.g. DoubleValues can easily be converted to Double and could use an underlying Aggregator<Double,?>

getValue

protected abstract PT getValue(VT value)

Get the value out of a value type.