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

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.ScalarVisitor

public class ScalarVisitor
extends AllExpressionVisitor

Logical plan visitor which handles scalar projections. It will find or create a LOStore and a soft link between the store operator to a scalar expression. It will also sync the file name between the store and scalar expression.

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

ScalarVisitor(OperatorPlan plan, PigContext pigContext, String scope)

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

ScalarVisitor

public ScalarVisitor(OperatorPlan plan,
                     PigContext pigContext,
                     String scope)
              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