org.apache.pig.newplan.optimizer
Interface PlanTransformListener
- All Known Implementing Classes:
- ProjectionPatcher, SchemaPatcher
@InterfaceAudience.Private
@InterfaceStability.Unstable
public interface PlanTransformListener
An interface to describe listeners that are notified when a plan is
modified. The purpose of these listeners is to make modifications to
annotations on the plan after the plan is modified. For example, if there
is a plan that has ... -> Join -> Filter -> ... which is transformed
by pushing the filter before the join, then the input schema of the filter
will mostly likely change. A schema listener can be used to make these
changes.
transformed
void transformed(OperatorPlan fp,
OperatorPlan tp)
throws FrontendException
- Notification that a plan has been transformed. The listener is free in
this method to make changes to the annotations on the plan now that it
has been transformed.
- Parameters:
fp
- the full plan that has been transformedtp
- a plan containing only the operators that have been transformed
- Throws:
FrontendException
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