Package org.apache.flink.runtime.state.v2.ttl

Class TtlAggregateFunction<IN,ACC,OUT>

java.lang.Object

org.apache.flink.runtime.state.ttl.AbstractTtlDecorator<AggregateFunction<IN,ACC,OUT>>

org.apache.flink.runtime.state.v2.ttl.TtlAggregateFunction<IN,ACC,OUT>

Type Parameters:

IN - The type of the values that are aggregated (input values)

ACC - The type of the accumulator (intermediate aggregate state).

OUT - The type of the aggregated result

All Implemented Interfaces:

Serializable, AggregateFunction<IN,TtlValue<ACC>,OUT>, Function

public class TtlAggregateFunction<IN,ACC,OUT>
extends AbstractTtlDecorator<AggregateFunction<IN,ACC,OUT>>
implements AggregateFunction<IN,TtlValue<ACC>,OUT>

This class wraps aggregating function with TTL logic.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.flink.runtime.state.ttl.AbstractTtlDecorator

config, original, returnExpired, timeProvider, ttl, updateTsOnRead

Constructor Summary

Constructors

Constructor	Description
TtlAggregateFunction(AggregateFunction<IN,ACC,OUT> aggFunction, StateTtlConfig config, TtlTimeProvider timeProvider)

Method Summary

Modifier and Type	Method	Description
TtlValue<ACC>	add(IN value, TtlValue<ACC> accumulator)	Adds the given input value to the given accumulator, returning the new accumulator value.
TtlValue<ACC>	createAccumulator()	Creates a new accumulator, starting a new aggregate.
OUT	getResult(TtlValue<ACC> accumulator)	Gets the result of the aggregation from the accumulator.
TtlValue<ACC>	merge(TtlValue<ACC> a, TtlValue<ACC> b)	Merges two accumulators, returning an accumulator with the merged state.

Methods inherited from class org.apache.flink.runtime.state.ttl.AbstractTtlDecorator

expired, getElementWithTtlCheck, getUnexpired, getWithTtlCheckAndUpdate, getWrappedWithTtlCheckAndUpdate, rewrapWithNewTs, wrapWithTs

Methods inherited from class java.lang.Object

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

Constructor Detail

TtlAggregateFunction

public TtlAggregateFunction(AggregateFunction<IN,ACC,OUT> aggFunction,
                            StateTtlConfig config,
                            TtlTimeProvider timeProvider)

Method Detail

createAccumulator

public TtlValue<ACC> createAccumulator()

Description copied from interface: AggregateFunction

Creates a new accumulator, starting a new aggregate.

The new accumulator is typically meaningless unless a value is added via AggregateFunction.add(Object, Object).

The accumulator is the state of a running aggregation. When a program has multiple aggregates in progress (such as per key and window), the state (per key and window) is the size of the accumulator.

Specified by:

createAccumulator in interface AggregateFunction<IN,ACC,OUT>

Returns:

A new accumulator, corresponding to an empty aggregate.

add

public TtlValue<ACC> add(IN value,
                         TtlValue<ACC> accumulator)

Description copied from interface: AggregateFunction

Adds the given input value to the given accumulator, returning the new accumulator value.

For efficiency, the input accumulator may be modified and returned.

Specified by:

add in interface AggregateFunction<IN,ACC,OUT>

Parameters:

value - The value to add

accumulator - The accumulator to add the value to

Returns:

The accumulator with the updated state

getResult

public OUT getResult(TtlValue<ACC> accumulator)

Description copied from interface: AggregateFunction

Gets the result of the aggregation from the accumulator.

Specified by:

getResult in interface AggregateFunction<IN,ACC,OUT>

Parameters:

accumulator - The accumulator of the aggregation

Returns:

The final aggregation result.

merge

public TtlValue<ACC> merge(TtlValue<ACC> a,
                           TtlValue<ACC> b)

Description copied from interface: AggregateFunction

Merges two accumulators, returning an accumulator with the merged state.

This function may reuse any of the given accumulators as the target for the merge and return that. The assumption is that the given accumulators will not be used any more after having been passed to this function.

Specified by:

merge in interface AggregateFunction<IN,ACC,OUT>

Parameters:

a - An accumulator to merge

b - Another accumulator to merge

Returns:

The accumulator with the merged state