org.apache.pig.newplan.logical.visitor
Class ColumnAliasConversionVisitor

java.lang.Object
  org.apache.pig.newplan.PlanVisitor
      org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor
          org.apache.pig.newplan.logical.optimizer.AllExpressionVisitor
              org.apache.pig.newplan.logical.visitor.ColumnAliasConversionVisitor

public class ColumnAliasConversionVisitor
extends AllExpressionVisitor

Logical plan visitor which will convert all column alias references to column indexes, using the underlying anonymous expression plan visitor.

Field Summary

Fields inherited from class org.apache.pig.newplan.logical.optimizer.AllExpressionVisitor

currentOp

Fields inherited from class org.apache.pig.newplan.PlanVisitor

currentWalker, DEFAULT_SCOPE, plan

Constructor Summary

ColumnAliasConversionVisitor(OperatorPlan plan)

Method Summary

protected LogicalExpressionVisitor

getVisitor(LogicalExpressionPlan exprPlan) Get a new instance of the expression visitor to apply to a given expression.

Methods inherited from class org.apache.pig.newplan.logical.optimizer.AllExpressionVisitor

visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor

visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class org.apache.pig.newplan.PlanVisitor

getPlan, popWalker, pushWalker, visit

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ColumnAliasConversionVisitor

public ColumnAliasConversionVisitor(OperatorPlan plan)
                             throws FrontendException

Throws:

FrontendException

Method Detail

getVisitor

protected LogicalExpressionVisitor getVisitor(LogicalExpressionPlan exprPlan)
                                       throws FrontendException

Description copied from class: AllExpressionVisitor

Get a new instance of the expression visitor to apply to a given expression.

Specified by:

getVisitor in class AllExpressionVisitor

Parameters:

exprPlan - LogicalExpressionPlan that will be visited

Returns:

a new LogicalExpressionVisitor for that expression

Throws:

FrontendException