org.apache.pig.pen.util
Class PreOrderDepthFirstWalker<O extends Operator,P extends OperatorPlan<O>>
java.lang.Object
org.apache.pig.impl.plan.PlanWalker<O,P>
org.apache.pig.pen.util.PreOrderDepthFirstWalker<O,P>
public class PreOrderDepthFirstWalker<O extends Operator,P extends OperatorPlan<O>>
- extends PlanWalker<O,P>
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
PreOrderDepthFirstWalker
public PreOrderDepthFirstWalker(P plan)
- Parameters:
plan
- Plan for this walker to traverse.
walk
public void walk(PlanVisitor<O,P> visitor)
throws VisitorException
- Begin traversing the graph.
- Specified by:
walk
in class PlanWalker<O extends Operator,P extends OperatorPlan<O>>
- Parameters:
visitor
- Visitor this walker is being used by.
- Throws:
VisitorException
- if an error is encountered while walking.
spawnChildWalker
public PlanWalker<O,P> spawnChildWalker(P plan)
- Description copied from class:
PlanWalker
- Return a new instance of this same type of walker for a subplan.
When this method is called the same type of walker with the
provided plan set as the plan, must be returned. This can then be
used to walk subplans. This allows abstract visitors to clone
walkers without knowning the type of walker their subclasses used.
- Specified by:
spawnChildWalker
in class PlanWalker<O extends Operator,P extends OperatorPlan<O>>
- Parameters:
plan
- Plan for the new walker.
- Returns:
- Instance of the same type of walker with mPlan set to plan.
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