org.apache.flink.streaming.api.watermark

类 Watermark

java.lang.Object

org.apache.flink.streaming.runtime.streamrecord.StreamElement

org.apache.flink.streaming.api.watermark.Watermark

@PublicEvolving
public final class Watermark
extends StreamElement

A Watermark tells operators that no elements with a timestamp older or equal to the watermark timestamp should arrive at the operator. Watermarks are emitted at the sources and propagate through the operators of the topology. Operators must themselves emit watermarks to downstream operators using Output.emitWatermark(Watermark). Operators that do not internally buffer elements can always forward the watermark that they receive. Operators that buffer elements, such as window operators, must forward a watermark after emission of elements that is triggered by the arriving watermark.

In some cases a watermark is only a heuristic and operators should be able to deal with late elements. They can either discard those or update the result and emit updates/retractions to downstream operations.

When a source closes it will emit a final watermark with timestamp Long.MAX_VALUE. When an operator receives this it will know that no more input will be arriving in the future.

字段概要

字段

限定符和类型	字段和说明
static Watermark	MAX_WATERMARK The watermark that signifies end-of-event-time.

构造器概要

构造器

构造器和说明
Watermark(long timestamp) Creates a new watermark with the given timestamp in milliseconds.

方法概要

限定符和类型	方法和说明
boolean	equals(Object o)
long	getTimestamp() Returns the timestamp associated with this Watermark in milliseconds.
int	hashCode()
String	toString()

从类继承的方法 org.apache.flink.streaming.runtime.streamrecord.StreamElement

asLatencyMarker, asRecord, asStreamStatus, asWatermark, isLatencyMarker, isRecord, isStreamStatus, isWatermark

从类继承的方法 java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

字段详细资料

MAX_WATERMARK

public static final Watermark MAX_WATERMARK

The watermark that signifies end-of-event-time.

构造器详细资料

Watermark

public Watermark(long timestamp)

Creates a new watermark with the given timestamp in milliseconds.

方法详细资料

getTimestamp

public long getTimestamp()

Returns the timestamp associated with this Watermark in milliseconds.

equals

public boolean equals(Object o)

覆盖:

equals 在类中 Object

hashCode

public int hashCode()

覆盖:

hashCode 在类中 Object

toString

public String toString()

覆盖:

toString 在类中 Object