org.apache.flink.streaming.api.transformations

Class CoFeedbackTransformation<F>

java.lang.Object

org.apache.flink.streaming.api.transformations.StreamTransformation<F>

org.apache.flink.streaming.api.transformations.CoFeedbackTransformation<F>

Type Parameters:

F - The type of the feedback elements.

@Internal
public class CoFeedbackTransformation<F>
extends StreamTransformation<F>

This represents a feedback point in a topology. The type of the feedback elements need not match the type of the upstream StreamTransformation because the only allowed operations after a CoFeedbackTransformation are TwoInputTransformations. The upstream StreamTransformation will be connected to the first input of the Co-Transform while the feedback edges will be connected to the second input.

Both the partitioning of the input and the feedback edges is preserved. They can also have differing partitioning strategies. This requires, however, that the parallelism of the feedback StreamTransformations must match the parallelism of the input StreamTransformation.

The upstream StreamTransformation is not wired to this CoFeedbackTransformation. It is instead directly wired to the TwoInputTransformation after this CoFeedbackTransformation.

This is different from Iterations in batch processing.

See Also:

FeedbackTransformation

Field Summary

Fields inherited from class org.apache.flink.streaming.api.transformations.StreamTransformation

bufferTimeout, id, idCounter, name, outputType, typeUsed

Constructor Summary

Constructors

Constructor and Description
CoFeedbackTransformation(int parallelism, TypeInformation<F> feedbackType, Long waitTime) Creates a new CoFeedbackTransformation from the given input.

Method Summary

Modifier and Type	Method and Description
void	addFeedbackEdge(StreamTransformation<F> transform) Adds a feedback edge.
List<StreamTransformation<F>>	getFeedbackEdges() Returns the list of feedback StreamTransformations.
Collection<StreamTransformation<?>>	getTransitivePredecessors() Returns all transitive predecessor StreamTransformations of this StreamTransformation.
Long	getWaitTime() Returns the wait time.
void	setChainingStrategy(ChainingStrategy strategy) Sets the chaining strategy of this StreamTransformation.

Methods inherited from class org.apache.flink.streaming.api.transformations.StreamTransformation

equals, getBufferTimeout, getCoLocationGroupKey, getId, getMaxParallelism, getMinResources, getName, getNewNodeId, getOutputType, getParallelism, getPreferredResources, getSlotSharingGroup, getUid, getUserProvidedNodeHash, hashCode, setBufferTimeout, setCoLocationGroupKey, setMaxParallelism, setName, setOutputType, setParallelism, setResources, setSlotSharingGroup, setUid, setUidHash, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

CoFeedbackTransformation

public CoFeedbackTransformation(int parallelism,
                                TypeInformation<F> feedbackType,
                                Long waitTime)

Creates a new CoFeedbackTransformation from the given input.

Parameters:

parallelism - The parallelism of the upstream StreamTransformation and the feedback edges.

feedbackType - The type of the feedback edges

waitTime - The wait time of the feedback operator. After the time expires the operation will close and not receive any more feedback elements.

Method Detail

addFeedbackEdge

public void addFeedbackEdge(StreamTransformation<F> transform)

Adds a feedback edge. The parallelism of the StreamTransformation must match the parallelism of the input StreamTransformation of the upstream StreamTransformation.

Parameters:

transform - The new feedback StreamTransformation.

getFeedbackEdges

public List<StreamTransformation<F>> getFeedbackEdges()

Returns the list of feedback StreamTransformations.

getWaitTime

public Long getWaitTime()

Returns the wait time. This is the amount of time that the feedback operator keeps listening for feedback elements. Once the time expires the operation will close and will not receive further elements.

setChainingStrategy

public final void setChainingStrategy(ChainingStrategy strategy)

Description copied from class: StreamTransformation

Sets the chaining strategy of this StreamTransformation.

Specified by:

setChainingStrategy in class StreamTransformation<F>

getTransitivePredecessors

public Collection<StreamTransformation<?>> getTransitivePredecessors()

Description copied from class: StreamTransformation

Returns all transitive predecessor StreamTransformations of this StreamTransformation. This is, for example, used when determining whether a feedback edge of an iteration actually has the iteration head as a predecessor.

Specified by:

getTransitivePredecessors in class StreamTransformation<F>

Returns:

The list of transitive predecessors.