@PublicEvolving public class SlidingEventTimeWindows extends WindowAssigner<Object,TimeWindow>
WindowAssigner
that windows elements into sliding windows based on the timestamp of the
elements. Windows can possibly overlap.
For example, in order to window into windows of 1 minute, every 10 seconds:
DataStream<Tuple2<String, Integer>> in = ...;
KeyedStream<Tuple2<String, Integer>, String> keyed = in.keyBy(...);
WindowedStream<Tuple2<String, Integer>, String, TimeWindow> windowed =
keyed.window(SlidingEventTimeWindows.of(Time.minutes(1), Time.seconds(10)));
WindowAssigner.WindowAssignerContext
Modifier | Constructor and Description |
---|---|
protected |
SlidingEventTimeWindows(long size,
long slide,
long offset) |
Modifier and Type | Method and 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(StreamExecutionEnvironment env)
Returns the default trigger associated with this
WindowAssigner . |
long |
getSize() |
long |
getSlide() |
TypeSerializer<TimeWindow> |
getWindowSerializer(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 SlidingEventTimeWindows |
of(Time size,
Time slide)
Creates a new
SlidingEventTimeWindows WindowAssigner that assigns elements to
sliding time windows based on the element timestamp. |
static SlidingEventTimeWindows |
of(Time size,
Time slide,
Time offset)
Creates a new
SlidingEventTimeWindows WindowAssigner that assigns elements to
time windows based on the element timestamp and offset. |
String |
toString() |
protected SlidingEventTimeWindows(long size, long slide, long offset)
public Collection<TimeWindow> assignWindows(Object element, long timestamp, WindowAssigner.WindowAssignerContext context)
WindowAssigner
Collection
of windows that should be assigned to the element.assignWindows
in class WindowAssigner<Object,TimeWindow>
element
- The element to which windows should be assigned.timestamp
- The timestamp of the element.context
- The WindowAssigner.WindowAssignerContext
in which the assigner operates.public long getSize()
public long getSlide()
public Trigger<Object,TimeWindow> getDefaultTrigger(StreamExecutionEnvironment env)
WindowAssigner
WindowAssigner
.getDefaultTrigger
in class WindowAssigner<Object,TimeWindow>
public static SlidingEventTimeWindows of(Time size, Time slide)
SlidingEventTimeWindows
WindowAssigner
that assigns elements to
sliding time windows based on the element timestamp.size
- The size of the generated windows.slide
- The slide interval of the generated windows.public static SlidingEventTimeWindows of(Time size, Time slide, Time offset)
SlidingEventTimeWindows
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(Time.hours(1),Time.minutes(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(Time.days(1),Time.hours(-8))
.
The parameter of offset is Time.hours(-8))
since UTC+08:00 is 8 hours earlier than
UTC time.
size
- The size of the generated windows.slide
- The slide interval of the generated windows.offset
- The offset which window start would be shifted by.public TypeSerializer<TimeWindow> getWindowSerializer(ExecutionConfig executionConfig)
WindowAssigner
TypeSerializer
for serializing windows that are assigned by this WindowAssigner
.getWindowSerializer
in class WindowAssigner<Object,TimeWindow>
public boolean isEventTime()
WindowAssigner
true
if elements are assigned to windows based on event time, false
otherwise.isEventTime
in class WindowAssigner<Object,TimeWindow>
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