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

java.lang.Object
  extended by org.apache.pig.newplan.PlanVisitor
      extended by org.apache.pig.newplan.logical.relational.LogicalRelationalNodesVisitor
          extended by org.apache.pig.newplan.logical.optimizer.AllExpressionVisitor
              extended by 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


Copyright © 2007-2012 The Apache Software Foundation