org.apache.flink.streaming.api.functions

接口 TimestampExtractor<T>

类型参数:

T - The type of the elements that this function can extract timestamps from

所有超级接口:

org.apache.flink.api.common.functions.Function, Serializable

已过时。

This class has been replaced by AssignerWithPeriodicWatermarks and AssignerWithPunctuatedWatermarks

@Deprecated
public interface TimestampExtractor<T>
extends org.apache.flink.api.common.functions.Function

Interface for user functions that extract timestamps from elements.

The extractor must also keep track of the current watermark. The system will periodically retrieve this watermark using getCurrentWatermark() and submit it throughout the topology.

Note: If you know that timestamps are monotonically increasing you can use AscendingTimestampExtractor. This will keep track of watermarks.

另请参阅:

AssignerWithPeriodicWatermarks, AssignerWithPunctuatedWatermarks

方法概要

限定符和类型	方法和说明
long	extractTimestamp(T element, long currentTimestamp) 已过时。 Extracts a timestamp from an element.
long	extractWatermark(T element, long currentTimestamp) 已过时。 Asks the extractor if it wants to emit a watermark now that it has seen the given element.
long	getCurrentWatermark() 已过时。 Returns the current watermark.

方法详细资料

extractTimestamp

long extractTimestamp(T element,
                      long currentTimestamp)

已过时。

Extracts a timestamp from an element.

参数:

element - The element that the timestamp is extracted from.

currentTimestamp - The current internal timestamp of the element.

返回:

The new timestamp.

extractWatermark

long extractWatermark(T element,
                      long currentTimestamp)

已过时。

Asks the extractor if it wants to emit a watermark now that it has seen the given element. This is called right after extractTimestamp(T, long). With the same element. The method can return Long.MIN_VALUE to indicate that no watermark should be emitted, a value of 0 or greater will be emitted as a watermark if it is higher than the last-emitted watermark.

参数:

element - The element that we last saw.

currentTimestamp - The current timestamp of the element that we last saw.

返回:

Long.MIN_VALUE if no watermark should be emitted, positive value for emitting this value as a watermark.

getCurrentWatermark

long getCurrentWatermark()

已过时。

Returns the current watermark. This is periodically called by the system to determine the current watermark and forward it.

另请参阅:

Watermark