org.apache.flink.streaming.api.operators.async

Class AsyncWaitOperator<IN,OUT>

java.lang.Object

org.apache.flink.streaming.api.operators.AbstractStreamOperator<OUT>

org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

org.apache.flink.streaming.api.operators.async.AsyncWaitOperator<IN,OUT>

Type Parameters:

IN - Input type for the operator.

OUT - Output type for the operator.

All Implemented Interfaces:

Serializable, org.apache.flink.runtime.state.CheckpointListener, KeyContext, OneInputStreamOperator<IN,OUT>, OutputTypeConfigurable<OUT>, SetupableStreamOperator<OUT>, StreamOperator<OUT>, org.apache.flink.util.Disposable

@Internal
public class AsyncWaitOperator<IN,OUT>
extends AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>
implements OneInputStreamOperator<IN,OUT>

The AsyncWaitOperator allows to asynchronously process incoming stream records. For that the operator creates an ResultFuture which is passed to an AsyncFunction. Within the async function, the user can complete the async collector arbitrarily. Once the async collector has been completed, the result is emitted by the operator's emitter to downstream operators.

The operator offers different output modes depending on the chosen AsyncDataStream.OutputMode. In order to give exactly once processing guarantees, the operator stores all currently in-flight StreamElement in it's operator state. Upon recovery the recorded set of stream elements is replayed.

In case of chaining of this operator, it has to be made sure that the operators in the chain are opened tail to head. The reason for this is that an opened AsyncWaitOperator starts already emitting recovered StreamElement to downstream operators.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

AbstractStreamOperator.CountingOutput<OUT>

Field Summary

Fields inherited from class org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator

userFunction

Fields inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

chainingStrategy, config, latencyStats, LOG, metrics, output, timeServiceManager

Constructor Summary

Constructors

Constructor and Description
AsyncWaitOperator(AsyncFunction<IN,OUT> asyncFunction, long timeout, int capacity, AsyncDataStream.OutputMode outputMode, MailboxExecutor mailboxExecutor)

Method Summary

Modifier and Type	Method and Description
void	close() This method is called after all records have been added to the operators via the methods OneInputStreamOperator.processElement(StreamRecord), or TwoInputStreamOperator.processElement1(StreamRecord) and TwoInputStreamOperator.processElement2(StreamRecord).
void	initializeState(org.apache.flink.runtime.state.StateInitializationContext context) Stream operators with state which can be restored need to override this hook method.
void	open() This method is called immediately before any elements are processed, it should contain the operator's initialization logic, e.g.
void	processElement(StreamRecord<IN> element) Processes one element that arrived at this operator.
void	processWatermark(Watermark mark) Processes a Watermark.
void	setup(StreamTask<?,?> containingTask, StreamConfig config, Output<StreamRecord<OUT>> output) Initializes the operator.
void	snapshotState(org.apache.flink.runtime.state.StateSnapshotContext context) Stream operators with state, which want to participate in a snapshot need to override this hook method.

Methods inherited from class org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator

dispose, getUserFunction, getUserFunctionParameters, notifyCheckpointComplete, setOutputType

Methods inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

getChainingStrategy, getContainingTask, getCurrentKey, getExecutionConfig, getInternalTimerService, getKeyedStateBackend, getKeyedStateStore, getMetricGroup, getOperatorConfig, getOperatorID, getOperatorName, getOperatorStateBackend, getOrCreateKeyedState, getPartitionedState, getPartitionedState, getProcessingTimeService, getRuntimeContext, getUserCodeClassloader, initializeState, numEventTimeTimers, numProcessingTimeTimers, prepareSnapshotPreBarrier, processLatencyMarker, processLatencyMarker1, processLatencyMarker2, processWatermark1, processWatermark2, reportOrForwardLatencyMarker, setChainingStrategy, setCurrentKey, setKeyContextElement1, setKeyContextElement2, snapshotState

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.streaming.api.operators.OneInputStreamOperator

processLatencyMarker

Methods inherited from interface org.apache.flink.streaming.api.operators.StreamOperator

dispose, getChainingStrategy, getMetricGroup, getOperatorID, initializeState, prepareSnapshotPreBarrier, setChainingStrategy, setKeyContextElement1, setKeyContextElement2, snapshotState

Methods inherited from interface org.apache.flink.runtime.state.CheckpointListener

notifyCheckpointComplete

Methods inherited from interface org.apache.flink.streaming.api.operators.KeyContext

getCurrentKey, setCurrentKey

Constructor Detail

AsyncWaitOperator

public AsyncWaitOperator(@Nonnull
                         AsyncFunction<IN,OUT> asyncFunction,
                         long timeout,
                         int capacity,
                         @Nonnull
                         AsyncDataStream.OutputMode outputMode,
                         @Nonnull
                         MailboxExecutor mailboxExecutor)

Method Detail

setup

public void setup(StreamTask<?,?> containingTask,
                  StreamConfig config,
                  Output<StreamRecord<OUT>> output)

Description copied from interface: SetupableStreamOperator

Initializes the operator. Sets access to the context and the output.

Specified by:

setup in interface SetupableStreamOperator<OUT>

Overrides:

setup in class AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

open

public void open()
          throws Exception

Description copied from class: AbstractStreamOperator

This method is called immediately before any elements are processed, it should contain the operator's initialization logic, e.g. state initialization.

The default implementation does nothing.

Specified by:

open in interface StreamOperator<OUT>

Overrides:

open in class AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

Throws:

Exception - An exception in this method causes the operator to fail.

processElement

public void processElement(StreamRecord<IN> element)
                    throws Exception

Description copied from interface: OneInputStreamOperator

Processes one element that arrived at this operator. This method is guaranteed to not be called concurrently with other methods of the operator.

Specified by:

processElement in interface OneInputStreamOperator<IN,OUT>

Throws:

Exception

processWatermark

public void processWatermark(Watermark mark)
                      throws Exception

Description copied from interface: OneInputStreamOperator

Processes a Watermark. This method is guaranteed to not be called concurrently with other methods of the operator.

Specified by:

processWatermark in interface OneInputStreamOperator<IN,OUT>

Overrides:

processWatermark in class AbstractStreamOperator<OUT>

Throws:

Exception

See Also:

Watermark

snapshotState

public void snapshotState(org.apache.flink.runtime.state.StateSnapshotContext context)
                   throws Exception

Description copied from class: AbstractStreamOperator

Stream operators with state, which want to participate in a snapshot need to override this hook method.

Overrides:

snapshotState in class AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

Parameters:

context - context that provides information and means required for taking a snapshot

Throws:

Exception

initializeState

public void initializeState(org.apache.flink.runtime.state.StateInitializationContext context)
                     throws Exception

Description copied from class: AbstractStreamOperator

Stream operators with state which can be restored need to override this hook method.

Overrides:

initializeState in class AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

Parameters:

context - context that allows to register different states.

Throws:

Exception

close

public void close()
           throws Exception

Description copied from class: AbstractStreamOperator

This method is called after all records have been added to the operators via the methods OneInputStreamOperator.processElement(StreamRecord), or TwoInputStreamOperator.processElement1(StreamRecord) and TwoInputStreamOperator.processElement2(StreamRecord).

The method is expected to flush all remaining buffered data. Exceptions during this flushing of buffered should be propagated, in order to cause the operation to be recognized asa failed, because the last data items are not processed properly.

Specified by:

close in interface StreamOperator<OUT>

Overrides:

close in class AbstractUdfStreamOperator<OUT,AsyncFunction<IN,OUT>>

Throws:

Exception - An exception in this method causes the operator to fail.