T
- The elements that get timestamps assigned.public class IngestionTimeExtractor<T> extends Object implements AssignerWithPeriodicWatermarks<T>
If this assigner is used after a stream source, it realizes "ingestion time" semantics.
构造器和说明 |
---|
IngestionTimeExtractor() |
限定符和类型 | 方法和说明 |
---|---|
long |
extractTimestamp(T element,
long previousElementTimestamp)
Assigns a timestamp to an element, in milliseconds since the Epoch.
|
Watermark |
getCurrentWatermark()
Returns the current watermark.
|
public long extractTimestamp(T element, long previousElementTimestamp)
TimestampAssigner
The method is passed the previously assigned timestamp of the element.
That previous timestamp may have been assigned from a previous assigner,
by ingestion time. If the element did not carry a timestamp before, this value is
Long.MIN_VALUE
.
extractTimestamp
在接口中 TimestampAssigner<T>
element
- The element that the timestamp will be assigned to.previousElementTimestamp
- The previous internal timestamp of the element,
or a negative value, if no timestamp has been assigned yet.public Watermark getCurrentWatermark()
AssignerWithPeriodicWatermarks
null
to
indicate that no new Watermark is available.
The returned watermark will be emitted only if it is non-null and its timestamp is larger than that of the previously emitted watermark (to preserve the contract of ascending watermarks). If the current watermark is still identical to the previous one, no progress in event time has happened since the previous call to this method. If a null value is returned, or the timestamp of the returned watermark is smaller than that of the last emitted one, then no new watermark will be generated.
The interval in which this method is called and Watermarks are generated
depends on ExecutionConfig.getAutoWatermarkInterval()
.
getCurrentWatermark
在接口中 AssignerWithPeriodicWatermarks<T>
Null
, if no watermark should be emitted, or the next watermark to emit.Watermark
,
ExecutionConfig.getAutoWatermarkInterval()
Copyright © 2014–2019 The Apache Software Foundation. All rights reserved.