com.metamatrix.query.sql.visitor
Class EvaluatableVisitor

java.lang.Object
  com.metamatrix.query.sql.LanguageVisitor
      com.metamatrix.query.sql.visitor.EvaluatableVisitor

public class EvaluatableVisitor
extends LanguageVisitor

This visitor class will traverse a language object tree, and determine if the current expression can be evaluated

Nested Class Summary

static class

EvaluatableVisitor.EvaluationLevel

Constructor Summary

EvaluatableVisitor()

Method Summary

static boolean	isEvaluatable(LanguageObject obj, EvaluatableVisitor.EvaluationLevel target)
static boolean	isFullyEvaluatable(LanguageObject obj, boolean duringPlanning) Should be called to check if the object can fully evaluated
static boolean	needsProcessingEvaluation(LanguageObject obj)
void	visit(AggregateSymbol obj)
void	visit(Constant obj)
void	visit(DependentSetCriteria obj)
void	visit(ElementSymbol obj)
void	visit(ExistsCriteria obj)
void	visit(ExpressionSymbol obj)
void	visit(Function obj)
void	visit(Reference obj) We assume the non-push down for correlation variables, then make specific checks when correlated variables are allowed.
void	visit(ScalarSubquery obj)
void	visit(StoredProcedure proc)
void	visit(SubqueryCompareCriteria obj)
void	visit(SubquerySetCriteria obj)
static boolean	willBecomeConstant(LanguageObject obj) Will return true if the expression can be deterministically evaluated at runtime, but it may not be evaluatable during planning
static boolean	willBecomeConstant(LanguageObject obj, boolean pushdown)

Methods inherited from class com.metamatrix.query.sql.LanguageVisitor

setAbort, shouldAbort, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class java.lang.Object

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

Constructor Detail

EvaluatableVisitor

public EvaluatableVisitor()

Method Detail

visit

public void visit(Function obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(Constant obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(ElementSymbol obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(ExpressionSymbol obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(AggregateSymbol obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(Reference obj)

We assume the non-push down for correlation variables, then make specific checks when correlated variables are allowed.

Overrides:

visit in class LanguageVisitor

visit

public void visit(StoredProcedure proc)

Overrides:

visit in class LanguageVisitor

visit

public void visit(ScalarSubquery obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(DependentSetCriteria obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(ExistsCriteria obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(SubquerySetCriteria obj)

Overrides:

visit in class LanguageVisitor

visit

public void visit(SubqueryCompareCriteria obj)

Overrides:

visit in class LanguageVisitor

willBecomeConstant

public static final boolean willBecomeConstant(LanguageObject obj)

Will return true if the expression can be deterministically evaluated at runtime, but it may not be evaluatable during planning

isFullyEvaluatable

public static final boolean isFullyEvaluatable(LanguageObject obj,
                                               boolean duringPlanning)

Should be called to check if the object can fully evaluated

isEvaluatable

public static final boolean isEvaluatable(LanguageObject obj,
                                          EvaluatableVisitor.EvaluationLevel target)

willBecomeConstant

public static final boolean willBecomeConstant(LanguageObject obj,
                                               boolean pushdown)

needsProcessingEvaluation

public static final boolean needsProcessingEvaluation(LanguageObject obj)