org.apache.beam.sdk

Interface Pipeline.PipelineVisitor

All Known Implementing Classes:

GearpumpPipelineTranslator, Pipeline.PipelineVisitor.Defaults, SparkNativePipelineVisitor, SparkRunner.Evaluator

Enclosing class:

Pipeline

@Internal
public static interface Pipeline.PipelineVisitor

For internal use only; no backwards-compatibility guarantees.

A Pipeline.PipelineVisitor can be passed into Pipeline.traverseTopologically(org.apache.beam.sdk.Pipeline.PipelineVisitor) to be called for each of the transforms and values in the Pipeline.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Pipeline.PipelineVisitor.CompositeBehavior Control enum for indicating whether or not a traversal should process the contents of a composite transform or not.
static class	Pipeline.PipelineVisitor.Defaults Default no-op Pipeline.PipelineVisitor that enters all composite transforms.

Method Summary

Modifier and Type	Method and Description
Pipeline.PipelineVisitor.CompositeBehavior	enterCompositeTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node) Called for each composite transform after all topological predecessors have been visited but before any of its component transforms.
void	enterPipeline(Pipeline p) Called before visiting anything values or transforms, as many uses of a visitor require access to the Pipeline object itself.
void	leaveCompositeTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node) Called for each composite transform after all of its component transforms and their outputs have been visited.
void	leavePipeline(Pipeline pipeline) Called when all values and transforms in a Pipeline have been visited.
void	visitPrimitiveTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node) Called for each primitive transform after all of its topological predecessors and inputs have been visited.
void	visitValue(PValue value, org.apache.beam.sdk.runners.TransformHierarchy.Node producer) Called for each value after the transform that produced the value has been visited.

Method Detail

enterPipeline

void enterPipeline(Pipeline p)

Called before visiting anything values or transforms, as many uses of a visitor require access to the Pipeline object itself.

enterCompositeTransform

Pipeline.PipelineVisitor.CompositeBehavior enterCompositeTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node)

Called for each composite transform after all topological predecessors have been visited but before any of its component transforms.

The return value controls whether or not child transforms are visited.

leaveCompositeTransform

void leaveCompositeTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node)

Called for each composite transform after all of its component transforms and their outputs have been visited.

visitPrimitiveTransform

void visitPrimitiveTransform(org.apache.beam.sdk.runners.TransformHierarchy.Node node)

Called for each primitive transform after all of its topological predecessors and inputs have been visited.

visitValue

void visitValue(PValue value,
                org.apache.beam.sdk.runners.TransformHierarchy.Node producer)

Called for each value after the transform that produced the value has been visited.

leavePipeline

void leavePipeline(Pipeline pipeline)

Called when all values and transforms in a Pipeline have been visited.