org.apache.tajo.plan.exprrewrite.rules

Class ConstantPropagation

java.lang.Object

org.apache.tajo.plan.expr.SimpleEvalNodeVisitor<LogicalPlanner.PlanContext>

org.apache.tajo.plan.exprrewrite.rules.ConstantPropagation

All Implemented Interfaces:

EvalTreeOptimizationRule

public class ConstantPropagation
extends SimpleEvalNodeVisitor<LogicalPlanner.PlanContext>
implements EvalTreeOptimizationRule

It replaces all field references which actually point to constant values by constant values. In order to maximize the effectiveness of constant folding, ConstantPropagation should be performed after constant folding.

Constructor Summary

Constructors

Constructor and Description
ConstantPropagation()

Method Summary

Methods

Modifier and Type	Method and Description
EvalNode	optimize(LogicalPlanner.PlanContext context, EvalNode evalNode)
EvalNode	visitBinaryEval(LogicalPlanner.PlanContext context, Stack<EvalNode> stack, BinaryEval binaryEval)
EvalNode	visitFuncCall(LogicalPlanner.PlanContext context, FunctionEval function, Stack<EvalNode> stack)
EvalNode	visitUnaryEval(LogicalPlanner.PlanContext context, Stack<EvalNode> stack, UnaryEval unaryEval)

Methods inherited from class org.apache.tajo.plan.expr.SimpleEvalNodeVisitor

visit, visitBetween, visitCaseWhen, visitConst, visitDefaultFunctionEval, visitField, visitIfThen, visitInPredicate, visitRowConstant

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantPropagation

public ConstantPropagation()

Method Detail

optimize

public EvalNode optimize(LogicalPlanner.PlanContext context,
                EvalNode evalNode)

Specified by:

optimize in interface EvalTreeOptimizationRule

visitBinaryEval

public EvalNode visitBinaryEval(LogicalPlanner.PlanContext context,
                       Stack<EvalNode> stack,
                       BinaryEval binaryEval)

Overrides:

visitBinaryEval in class SimpleEvalNodeVisitor<LogicalPlanner.PlanContext>

visitUnaryEval

public EvalNode visitUnaryEval(LogicalPlanner.PlanContext context,
                      Stack<EvalNode> stack,
                      UnaryEval unaryEval)

Overrides:

visitUnaryEval in class SimpleEvalNodeVisitor<LogicalPlanner.PlanContext>

visitFuncCall

public EvalNode visitFuncCall(LogicalPlanner.PlanContext context,
                     FunctionEval function,
                     Stack<EvalNode> stack)

Overrides:

visitFuncCall in class SimpleEvalNodeVisitor<LogicalPlanner.PlanContext>