org.apache.beam.sdk.runners

Class TransformHierarchy

java.lang.Object

org.apache.beam.sdk.runners.TransformHierarchy

@Internal
public class TransformHierarchy
extends java.lang.Object

For internal use only; no backwards-compatibility guarantees.

Captures information about a collection of transformations and their associated PCollections.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	TransformHierarchy.Node Provides internal tracking of transform relationships with helper methods for initialization and ordered visitation.

Constructor Summary

Constructors

Constructor and Description
TransformHierarchy()

Method Summary

Modifier and Type	Method and Description
void	finishSpecifyingInput() Finish specifying all of the input PValues of the current TransformHierarchy.Node.
TransformHierarchy.Node	getCurrent()
void	popNode() Pops the current node off the top of the stack, finishing it.
TransformHierarchy.Node	pushNode(java.lang.String name, PInput input, PTransform<?,?> transform) Adds the named PTransform consuming the provided PInput as a node in this TransformHierarchy as a child of the current node, and sets it to be the current node.
TransformHierarchy.Node	replaceNode(TransformHierarchy.Node existing, PInput input, PTransform<?,?> transform)
void	replaceOutputs(java.util.Map<PCollection<?>,PTransformOverrideFactory.ReplacementOutput> originalToReplacement) Recursively replace the outputs of the current TransformHierarchy.Node with the original outputs of the node it is replacing.
void	setOutput(POutput output) Set the output of the current TransformHierarchy.Node.
java.util.Set<PValue>	visit(Pipeline.PipelineVisitor visitor)

Methods inherited from class java.lang.Object

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

Constructor Detail

TransformHierarchy

public TransformHierarchy()

Method Detail

pushNode

public TransformHierarchy.Node pushNode(java.lang.String name,
                                        PInput input,
                                        PTransform<?,?> transform)

Adds the named PTransform consuming the provided PInput as a node in this TransformHierarchy as a child of the current node, and sets it to be the current node.

This call should be finished by expanding and recursively calling pushNode(String, PInput, PTransform), calling finishSpecifyingInput(), setting the output with setOutput(POutput), and ending with a call to popNode().

Returns:

the added node

replaceNode

public TransformHierarchy.Node replaceNode(TransformHierarchy.Node existing,
                                           PInput input,
                                           PTransform<?,?> transform)

finishSpecifyingInput

public void finishSpecifyingInput()

Finish specifying all of the input PValues of the current TransformHierarchy.Node. Ensures that all of the inputs to the current node have been fully specified, and have been produced by a node in this graph.

setOutput

public void setOutput(POutput output)

Set the output of the current TransformHierarchy.Node. If the output is new (setOutput has not previously been called with it as the parameter), the current node is set as the producer of that POutput.

Also validates the output - specifically, a Primitive PTransform produces all of its outputs, and a Composite PTransform produces none of its outputs. Verifies that the expanded output does not contain PValues produced by both this node and other nodes.

replaceOutputs

public void replaceOutputs(java.util.Map<PCollection<?>,PTransformOverrideFactory.ReplacementOutput> originalToReplacement)

Recursively replace the outputs of the current TransformHierarchy.Node with the original outputs of the node it is replacing. No value that is a key in originalToReplacement may be present within the TransformHierarchy after this method completes.

popNode

public void popNode()

Pops the current node off the top of the stack, finishing it. Outputs of the node are finished once they are consumed as input.

visit

public java.util.Set<PValue> visit(Pipeline.PipelineVisitor visitor)

getCurrent

public TransformHierarchy.Node getCurrent()