org.apache.pig.impl.plan
Interfaces 
PlanValidationExecutor
Classes 
CompilationMessageCollector
CompilationMessageCollector.Message
DependencyOrderWalker
DependencyOrderWalkerWOSeenChk
DepthFirstWalker
NodeIdGenerator
Operator
OperatorKey
OperatorPlan
PlanValidator
PlanVisitor
PlanWalker
Enums 
CompilationMessageCollector.MessageType
Exceptions 
PlanException
PlanValidationException
VisitorException