org.apache.flink.streaming.api.operators

Class StreamSource.NonTimestampContext<T>

java.lang.Object

org.apache.flink.streaming.api.operators.StreamSource.NonTimestampContext<T>

All Implemented Interfaces:

SourceFunction.SourceContext<T>

Enclosing class:

StreamSource<OUT,SRC extends SourceFunction<OUT>>

public static class StreamSource.NonTimestampContext<T>
extends Object
implements SourceFunction.SourceContext<T>

A source context that attached -1 as a timestamp to all records, and that does not forward watermarks.

Constructor Summary

Constructors

Constructor and Description
NonTimestampContext(StreamSource<?,?> owner, Object lockingObject, Output<StreamRecord<T>> output)

Method Summary

Modifier and Type	Method and Description
void	close() This method is called by the system to shut down the context.
void	collect(T element) Emits one element from the source, without attaching a timestamp.
void	collectWithTimestamp(T element, long timestamp) Emits one element from the source, and attaches the given timestamp.
void	emitWatermark(Watermark mark) Emits the given Watermark.
Object	getCheckpointLock() Returns the checkpoint lock.

Methods inherited from class java.lang.Object

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

Constructor Detail

NonTimestampContext

public NonTimestampContext(StreamSource<?,?> owner,
                           Object lockingObject,
                           Output<StreamRecord<T>> output)

Method Detail

collect

public void collect(T element)

Description copied from interface: SourceFunction.SourceContext

Emits one element from the source, without attaching a timestamp. In most cases, this is the default way of emitting elements.

The timestamp that the element will get assigned depends on the time characteristic of the streaming program:

• On TimeCharacteristic.ProcessingTime, the element has no timestamp.
• On TimeCharacteristic.IngestionTime, the element gets the system's current time as the timestamp.
• On TimeCharacteristic.EventTime, the element will have no timestamp initially. It needs to get a timestamp (via a TimestampAssigner) before any time-dependent operation (like time windows).

Specified by:

collect in interface SourceFunction.SourceContext<T>

Parameters:

element - The element to emit

collectWithTimestamp

public void collectWithTimestamp(T element,
                                 long timestamp)

Description copied from interface: SourceFunction.SourceContext

Emits one element from the source, and attaches the given timestamp. This method is relevant for programs using TimeCharacteristic.EventTime, where the sources assign timestamps themselves, rather than relying on a TimestampAssigner on the stream.

On certain time characteristics, this timestamp may be ignored or overwritten. This allows programs to switch between the different time characteristics and behaviors without changing the code of the source functions.

• On TimeCharacteristic.ProcessingTime, the timestamp will be ignored, because processing time never works with element timestamps.
• On TimeCharacteristic.IngestionTime, the timestamp is overwritten with the system's current time, to realize proper ingestion time semantics.
• On TimeCharacteristic.EventTime, the timestamp will be used.

Specified by:

collectWithTimestamp in interface SourceFunction.SourceContext<T>

Parameters:

element - The element to emit

timestamp - The timestamp in milliseconds since the Epoch

emitWatermark

public void emitWatermark(Watermark mark)

Description copied from interface: SourceFunction.SourceContext

Emits the given Watermark. A Watermark of value t declares that no elements with a timestamp t' <= t will occur any more. If further such elements will be emitted, those elements are considered late.

This method is only relevant when running on TimeCharacteristic.EventTime. On TimeCharacteristic.ProcessingTime,Watermarks will be ignored. On TimeCharacteristic.IngestionTime, the Watermarks will be replaced by the automatic ingestion time watermarks.

Specified by:

emitWatermark in interface SourceFunction.SourceContext<T>

Parameters:

mark - The Watermark to emit

getCheckpointLock

public Object getCheckpointLock()

Description copied from interface: SourceFunction.SourceContext

Returns the checkpoint lock. Please refer to the class-level comment in SourceFunction for details about how to write a consistent checkpointed source.

Specified by:

getCheckpointLock in interface SourceFunction.SourceContext<T>

Returns:

The object to use as the lock

close

public void close()

Description copied from interface: SourceFunction.SourceContext

This method is called by the system to shut down the context.

Specified by:

close in interface SourceFunction.SourceContext<T>