Package org.apache.flink.streaming.api.windowing.assigners

Class EventTimeSessionWindows

java.lang.Object

org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<T,W>

org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

org.apache.flink.streaming.api.windowing.assigners.EventTimeSessionWindows

All Implemented Interfaces:

Serializable

@PublicEvolving
public class EventTimeSessionWindows
extends org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

A WindowAssigner that windows elements into sessions based on the timestamp of the elements. Windows cannot overlap.

For example, in order to window into windows of 1 minute, every 10 seconds:

 DataStream<Tuple2<String, Integer>> in = ...;
 KeyedStream<String, Tuple2<String, Integer>> keyed = in.keyBy(...);
 WindowedStream<Tuple2<String, Integer>, String, TimeWindows> windowed =
   keyed.window(EventTimeSessionWindows.withGap(Duration.ofMinutes(1)));
 

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner

org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner.MergeCallback<W extends Object>

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.windowing.assigners.WindowAssigner

org.apache.flink.streaming.api.windowing.assigners.WindowAssigner.WindowAssignerContext

Field Summary

Fields

Modifier and Type	Field	Description
protected long	sessionTimeout

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	EventTimeSessionWindows(long sessionTimeout)

Method Summary

Modifier and Type	Method	Description
Collection<org.apache.flink.streaming.api.windowing.windows.TimeWindow>	assignWindows(Object element, long timestamp, org.apache.flink.streaming.api.windowing.assigners.WindowAssigner.WindowAssignerContext context)
org.apache.flink.streaming.api.windowing.triggers.Trigger<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>	getDefaultTrigger()
org.apache.flink.api.common.typeutils.TypeSerializer<org.apache.flink.streaming.api.windowing.windows.TimeWindow>	getWindowSerializer(org.apache.flink.api.common.ExecutionConfig executionConfig)
boolean	isEventTime()
void	mergeWindows(Collection<org.apache.flink.streaming.api.windowing.windows.TimeWindow> windows, org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner.MergeCallback<org.apache.flink.streaming.api.windowing.windows.TimeWindow> c)	Merge overlapping TimeWindows.
String	toString()
static <T> DynamicEventTimeSessionWindows<T>	withDynamicGap(SessionWindowTimeGapExtractor<T> sessionWindowTimeGapExtractor)	Creates a new SessionWindows WindowAssigner that assigns elements to sessions based on the element timestamp.
static EventTimeSessionWindows	withGap(Duration size)	Creates a new SessionWindows WindowAssigner that assigns elements to sessions based on the element timestamp.

Methods inherited from class java.lang.Object

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

Field Detail

sessionTimeout

protected long sessionTimeout

Constructor Detail

EventTimeSessionWindows

protected EventTimeSessionWindows(long sessionTimeout)

Method Detail

assignWindows

public Collection<org.apache.flink.streaming.api.windowing.windows.TimeWindow> assignWindows(Object element,
                                                                                             long timestamp,
                                                                                             org.apache.flink.streaming.api.windowing.assigners.WindowAssigner.WindowAssignerContext context)

Specified by:

assignWindows in class org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

getDefaultTrigger

public org.apache.flink.streaming.api.windowing.triggers.Trigger<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow> getDefaultTrigger()

Specified by:

getDefaultTrigger in class org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

toString

public String toString()

Overrides:

toString in class Object

withGap

public static EventTimeSessionWindows withGap(Duration size)

Creates a new SessionWindows WindowAssigner that assigns elements to sessions based on the element timestamp.

Parameters:

size - The session timeout, i.e. the time gap between sessions

Returns:

The policy.

withDynamicGap

@PublicEvolving
public static <T> DynamicEventTimeSessionWindows<T> withDynamicGap(SessionWindowTimeGapExtractor<T> sessionWindowTimeGapExtractor)

Creates a new SessionWindows WindowAssigner that assigns elements to sessions based on the element timestamp.

Parameters:

sessionWindowTimeGapExtractor - The extractor to use to extract the time gap from the input elements

Returns:

The policy.

getWindowSerializer

public org.apache.flink.api.common.typeutils.TypeSerializer<org.apache.flink.streaming.api.windowing.windows.TimeWindow> getWindowSerializer(org.apache.flink.api.common.ExecutionConfig executionConfig)

Specified by:

getWindowSerializer in class org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

isEventTime

public boolean isEventTime()

Specified by:

isEventTime in class org.apache.flink.streaming.api.windowing.assigners.WindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>

mergeWindows

public void mergeWindows(Collection<org.apache.flink.streaming.api.windowing.windows.TimeWindow> windows,
                         org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner.MergeCallback<org.apache.flink.streaming.api.windowing.windows.TimeWindow> c)

Merge overlapping TimeWindows.

Specified by:

mergeWindows in class org.apache.flink.streaming.api.windowing.assigners.MergingWindowAssigner<Object,org.apache.flink.streaming.api.windowing.windows.TimeWindow>