Package org.apache.flink.table.runtime.operators.window.groupwindow.assigners

Class SessionWindowAssigner

java.lang.Object

org.apache.flink.table.runtime.operators.window.groupwindow.assigners.GroupWindowAssigner<W>

org.apache.flink.table.runtime.operators.window.groupwindow.assigners.MergingWindowAssigner<TimeWindow>

org.apache.flink.table.runtime.operators.window.groupwindow.assigners.SessionWindowAssigner

All Implemented Interfaces:

Serializable, InternalTimeWindowAssigner

public class SessionWindowAssigner
extends MergingWindowAssigner<TimeWindow>
implements InternalTimeWindowAssigner

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

See Also:

• Serialized Form

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SessionWindowAssigner(long sessionGap, boolean isEventTime)

Method Summary

Modifier and Type	Method	Description
Collection<TimeWindow>	assignWindows(org.apache.flink.table.data.RowData element, long timestamp)	Given the timestamp and element, returns the set of windows into which it should be placed.
org.apache.flink.api.common.typeutils.TypeSerializer<TimeWindow>	getWindowSerializer(org.apache.flink.api.common.ExecutionConfig executionConfig)	Returns a TypeSerializer for serializing windows that are assigned by this WindowAssigner.
boolean	isEventTime()	Returns true if elements are assigned to windows based on event time, false otherwise.
void	mergeWindows(TimeWindow newWindow, NavigableSet<TimeWindow> sortedWindows, MergeCallback<TimeWindow,Collection<TimeWindow>> callback)	Determines which windows (if any) should be merged.
String	toString()
SessionWindowAssigner	withEventTime()
static SessionWindowAssigner	withGap(Duration size)	Creates a new SessionWindowAssigner GroupWindowAssigner that assigns elements to sessions based on the timestamp.
SessionWindowAssigner	withProcessingTime()

Methods inherited from class org.apache.flink.table.runtime.operators.window.groupwindow.assigners.GroupWindowAssigner

open

Methods inherited from class java.lang.Object

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

Constructor Details

SessionWindowAssigner

protected SessionWindowAssigner(long sessionGap,
 boolean isEventTime)

Method Details

assignWindows

public Collection<TimeWindow> assignWindows(org.apache.flink.table.data.RowData element,
 long timestamp)

Description copied from class: GroupWindowAssigner

Given the timestamp and element, returns the set of windows into which it should be placed.

Specified by:

assignWindows in class GroupWindowAssigner<TimeWindow>

Parameters:

element - The element to which windows should be assigned.

timestamp - The timestamp of the element when GroupWindowAssigner.isEventTime() returns true, or the current system time when GroupWindowAssigner.isEventTime() returns false. The timestamp value is mapping to UTC milliseconds for splitting windows simply.

mergeWindows

public void mergeWindows(TimeWindow newWindow,
 NavigableSet<TimeWindow> sortedWindows,
 MergeCallback<TimeWindow,Collection<TimeWindow>> callback)

Description copied from class: MergingWindowAssigner

Determines which windows (if any) should be merged.

Specified by:

mergeWindows in class MergingWindowAssigner<TimeWindow>

Parameters:

newWindow - The new window

sortedWindows - The sorted window candidates.

callback - A callback that can be invoked to signal which windows should be merged.

getWindowSerializer

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

Description copied from class: GroupWindowAssigner

Returns a TypeSerializer for serializing windows that are assigned by this WindowAssigner.

Specified by:

getWindowSerializer in class GroupWindowAssigner<TimeWindow>

isEventTime

public boolean isEventTime()

Description copied from class: GroupWindowAssigner

Returns true if elements are assigned to windows based on event time, false otherwise.

Specified by:

isEventTime in class GroupWindowAssigner<TimeWindow>

toString

public String toString()

Specified by:

toString in class GroupWindowAssigner<TimeWindow>

withGap

public static SessionWindowAssigner withGap(Duration size)

Creates a new SessionWindowAssigner GroupWindowAssigner that assigns elements to sessions based on the timestamp.

Parameters:

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

Returns:

The policy.

withEventTime

public SessionWindowAssigner withEventTime()

Specified by:

withEventTime in interface InternalTimeWindowAssigner

Returns:

an InternalTimeWindowAssigner which in event time mode.

withProcessingTime

public SessionWindowAssigner withProcessingTime()

Specified by:

withProcessingTime in interface InternalTimeWindowAssigner

Returns:

an InternalTimeWindowAssigner which in processing time mode.