org.apache.flink.streaming.api.windowing.helper

Class Delta<DATA>

java.lang.Object

org.apache.flink.streaming.api.windowing.helper.WindowingHelper<DATA>

org.apache.flink.streaming.api.windowing.helper.Delta<DATA>

Type Parameters:

DATA - the data type handled by the delta function represented by this helper.

public class Delta<DATA>
extends WindowingHelper<DATA>

This helper represents a trigger or eviction policy based on a DeltaFunction.

Field Summary

Fields inherited from class org.apache.flink.streaming.api.windowing.helper.WindowingHelper

executionConfig

Constructor Summary

Constructors

Constructor and Description
Delta(DeltaFunction<DATA> deltaFunction, DATA initVal, double threshold) Creates a delta helper representing a delta count or eviction policy

Method Summary

Modifier and Type	Method and Description
static <DATA> Delta<DATA>	of(double threshold, DeltaFunction<DATA> deltaFunction, DATA initVal) Creates a delta helper representing a delta trigger or eviction policy.
EvictionPolicy<DATA>	toEvict() Method for encapsulating the EvictionPolicy.
TriggerPolicy<DATA>	toTrigger() Method for encapsulating the TriggerPolicy.

Methods inherited from class org.apache.flink.streaming.api.windowing.helper.WindowingHelper

setExecutionConfig

Methods inherited from class java.lang.Object

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

Constructor Detail

Delta

public Delta(DeltaFunction<DATA> deltaFunction,
             DATA initVal,
             double threshold)

Creates a delta helper representing a delta count or eviction policy

Parameters:

deltaFunction - The delta function which should be used to calculate the delta points.

initVal - The initial value which will be used to calculate the first delta.

threshold - The threshold used by the delta function.

Method Detail

toEvict

public EvictionPolicy<DATA> toEvict()

Description copied from class: WindowingHelper

Method for encapsulating the EvictionPolicy.

Specified by:

toEvict in class WindowingHelper<DATA>

Returns:

the eviction policy

toTrigger

public TriggerPolicy<DATA> toTrigger()

Description copied from class: WindowingHelper

Method for encapsulating the TriggerPolicy.

Specified by:

toTrigger in class WindowingHelper<DATA>

Returns:

the trigger policy

of

public static <DATA> Delta<DATA> of(double threshold,
                                    DeltaFunction<DATA> deltaFunction,
                                    DATA initVal)

Creates a delta helper representing a delta trigger or eviction policy.

This policy calculates a delta between the data point which triggered last and the currently arrived data point. It triggers if the delta is higher than a specified threshold.

In case it gets used for eviction, this policy starts from the first element of the buffer and removes all elements from the buffer which have a higher delta then the threshold. As soon as there is an element with a lower delta, the eviction stops.

Parameters:

deltaFunction - The delta function which should be used to calculate the delta points.

initVal - The initial value which will be used to calculate the first delta.

threshold - The threshold used by the delta function.

Returns:

Helper representing a delta trigger or eviction policy