org.apache.flink.streaming.api.functions.timestamps

类 BoundedOutOfOrdernessTimestampExtractor<T>

java.lang.Object

org.apache.flink.streaming.api.functions.timestamps.BoundedOutOfOrdernessTimestampExtractor<T>

所有已实现的接口:

Serializable, org.apache.flink.api.common.eventtime.TimestampAssigner<T>, org.apache.flink.api.common.functions.Function, AssignerWithPeriodicWatermarks<T>

public abstract class BoundedOutOfOrdernessTimestampExtractor<T>
extends Object
implements AssignerWithPeriodicWatermarks<T>

This is a AssignerWithPeriodicWatermarks used to emit Watermarks that lag behind the element with the maximum timestamp (in event time) seen so far by a fixed amount of time, t_late. This can help reduce the number of elements that are ignored due to lateness when computing the final result for a given window, in the case where we know that elements arrive no later than t_late units of time after the watermark that signals that the system event-time has advanced past their (event-time) timestamp.

另请参阅:

序列化表格

字段概要

从接口继承的字段 org.apache.flink.api.common.eventtime.TimestampAssigner

NO_TIMESTAMP

构造器概要

构造器

构造器和说明
BoundedOutOfOrdernessTimestampExtractor(Time maxOutOfOrderness)

方法概要

限定符和类型	方法和说明
abstract long	extractTimestamp(T element) Extracts the timestamp from the given element.
long	extractTimestamp(T element, long previousElementTimestamp) Assigns a timestamp to an element, in milliseconds since the Epoch.
Watermark	getCurrentWatermark() Returns the current watermark.
long	getMaxOutOfOrdernessInMillis()

从类继承的方法 java.lang.Object

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

构造器详细资料

BoundedOutOfOrdernessTimestampExtractor

public BoundedOutOfOrdernessTimestampExtractor(Time maxOutOfOrderness)

方法详细资料

getMaxOutOfOrdernessInMillis

public long getMaxOutOfOrdernessInMillis()

extractTimestamp

public abstract long extractTimestamp(T element)

Extracts the timestamp from the given element.

参数:

element - The element that the timestamp is extracted from.

返回:

The new timestamp.

getCurrentWatermark

public final Watermark getCurrentWatermark()

从接口复制的说明: AssignerWithPeriodicWatermarks

Returns the current watermark. This method is periodically called by the system to retrieve the current watermark. The method may return 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().

指定者:

getCurrentWatermark 在接口中 AssignerWithPeriodicWatermarks<T>

返回:

Null, if no watermark should be emitted, or the next watermark to emit.

另请参阅:

Watermark, ExecutionConfig.getAutoWatermarkInterval()

extractTimestamp

public final long extractTimestamp(T element,
                                   long previousElementTimestamp)

从接口复制的说明: TimestampAssigner

Assigns a timestamp to an element, in milliseconds since the Epoch.

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.

指定者:

extractTimestamp 在接口中 org.apache.flink.api.common.eventtime.TimestampAssigner<T>

参数:

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.

返回:

The new timestamp.