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ProjectNode

ProjectNode is an extension of the SingleSourcePlanNode abstraction for project nodes with select expressions (for SchemaKStream.select when building a SchemaKStream).

Contract

Select Expressions

List<SelectExpression> getSelectExpressions()

Used when:

  • ProjectNode is requested to buildStream
  • ProjectOperator is requested to open and createRowForSelectStar

Implementations

Creating Instance

ProjectNode takes the following to be created:

Abstract Class

ProjectNode is an abstract class and cannot be created directly. It is created indirectly for the concrete ProjectNodes.

Building SchemaKStream

SchemaKStream<?> buildStream(
  PlanBuildContext buildContext)

buildStream is part of the PlanNode abstraction.

buildStream requests the source PlanNode to build a SchemaKStream.

In the end, buildStream requests the SchemaKStream to select.