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

Class TumblingEventTimeWindows

java.lang.Object

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

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

All Implemented Interfaces:

Serializable

@PublicEvolving
public class TumblingEventTimeWindows
extends WindowAssigner<Object,TimeWindow>

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

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

 DataStream<Tuple2<String, Integer>> in = ...;
 KeyedStream<Tuple2<String, Integer>, String> keyed = in.keyBy(...);
 WindowedStream<Tuple2<String, Integer>, String, TimeWindow> windowed =
   keyed.window(TumblingEventTimeWindows.of(Duration.ofMinutes(1)));
 

See Also:

Serialized Form

Nested Class Summary

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

WindowAssigner.WindowAssignerContext

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	TumblingEventTimeWindows(long size, long offset, WindowStagger windowStagger)

Method Summary

Modifier and Type	Method	Description
Collection<TimeWindow>	assignWindows(Object element, long timestamp, WindowAssigner.WindowAssignerContext context)	Returns a Collection of windows that should be assigned to the element.
Trigger<Object,TimeWindow>	getDefaultTrigger()	Returns the default trigger associated with this WindowAssigner.
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.
static TumblingEventTimeWindows	of(Duration size)	Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp.
static TumblingEventTimeWindows	of(Duration size, Duration offset)	Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp and offset.
static TumblingEventTimeWindows	of(Duration size, Duration offset, WindowStagger windowStagger)	Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp, offset and a staggering offset, depending on the staggering policy.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

TumblingEventTimeWindows

protected TumblingEventTimeWindows(long size,
                                   long offset,
                                   WindowStagger windowStagger)

Method Detail

assignWindows

public Collection<TimeWindow> assignWindows(Object element,
                                            long timestamp,
                                            WindowAssigner.WindowAssignerContext context)

Description copied from class: WindowAssigner

Returns a Collection of windows that should be assigned to the element.

Specified by:

assignWindows in class WindowAssigner<Object,TimeWindow>

Parameters:

element - The element to which windows should be assigned.

timestamp - The timestamp of the element.

context - The WindowAssigner.WindowAssignerContext in which the assigner operates.

getDefaultTrigger

public Trigger<Object,TimeWindow> getDefaultTrigger()

Description copied from class: WindowAssigner

Returns the default trigger associated with this WindowAssigner.

1. If you override getDefaultTrigger(), the getDefaultTrigger() will be invoked and the getDefaultTrigger(StreamExecutionEnvironment env) won't be invoked. 2. If you don't override getDefaultTrigger(), the getDefaultTrigger(StreamExecutionEnvironment env) will be invoked in the default implementation of the getDefaultTrigger().

Specified by:

getDefaultTrigger in class WindowAssigner<Object,TimeWindow>

toString

public String toString()

Overrides:

toString in class Object

of

public static TumblingEventTimeWindows of(Duration size)

Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp.

Parameters:

size - The size of the generated windows.

Returns:

The time policy.

of

public static TumblingEventTimeWindows of(Duration size,
                                          Duration offset)

Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp and offset.

For example, if you want window a stream by hour,but window begins at the 15th minutes of each hour, you can use of(Duration.ofHours(1), Duration.ofMinutes(15)), then you will get time windows start at 0:15:00,1:15:00,2:15:00,etc.

Rather than that,if you are living in somewhere which is not using UTC±00:00 time, such as China which is using UTC+08:00,and you want a time window with size of one day, and window begins at every 00:00:00 of local time,you may use of(Duration.ofDays(1), Duration.ofHours(-8)). The parameter of offset is Duration.ofHours(-8)) since UTC+08:00 is 8 hours earlier than UTC time.

Parameters:

size - The size of the generated windows.

offset - The offset which window start would be shifted by.

of

@PublicEvolving
public static TumblingEventTimeWindows of(Duration size,
                                          Duration offset,
                                          WindowStagger windowStagger)

Creates a new TumblingEventTimeWindows WindowAssigner that assigns elements to time windows based on the element timestamp, offset and a staggering offset, depending on the staggering policy.

Parameters:

size - The size of the generated windows.

offset - The globalOffset which window start would be shifted by.

windowStagger - The utility that produces staggering offset in runtime.

getWindowSerializer

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

Description copied from class: WindowAssigner

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

Specified by:

getWindowSerializer in class WindowAssigner<Object,TimeWindow>

isEventTime

public boolean isEventTime()

Description copied from class: WindowAssigner

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

Specified by:

isEventTime in class WindowAssigner<Object,TimeWindow>