org.apache.derby.impl.sql.compile

Class RemapCRsVisitor

java.lang.Object

org.apache.derby.impl.sql.compile.RemapCRsVisitor

All Implemented Interfaces:

Visitor

public class RemapCRsVisitor
extends java.lang.Object
implements Visitor

Remap/unremap the CRs to the underlying expression.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	remap

Constructor Summary

Constructors

Constructor and Description
RemapCRsVisitor(boolean remap)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	skipChildren(Visitable node) No need to go below a SubqueryNode.
boolean	stopTraversal() Method that is called to see if query tree traversal should be stopped before visiting all nodes.
Visitable	visit(Visitable node) Don't do anything unless we have a ColumnReference node.
boolean	visitChildrenFirst(Visitable node) Method that is called to see if visit() should be called on the children of node before it is called on node itself.

Methods inherited from class java.lang.Object

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

Field Detail

remap

private boolean remap

Constructor Detail

RemapCRsVisitor

public RemapCRsVisitor(boolean remap)

Method Detail

visit

public Visitable visit(Visitable node)
                throws StandardException

Don't do anything unless we have a ColumnReference node.

Specified by:

visit in interface Visitor

Parameters:

node - the node to process

Returns:

me

Throws:

StandardException - on error

skipChildren

public boolean skipChildren(Visitable node)

No need to go below a SubqueryNode.

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

Whether or not to go below the node.

visitChildrenFirst

public boolean visitChildrenFirst(Visitable node)

Description copied from interface: Visitor

Method that is called to see if visit() should be called on the children of node before it is called on node itself. If this method always returns true, the visitor will walk the tree bottom-up. If it always returns false, the tree is visited top-down.

Specified by:

visitChildrenFirst in interface Visitor

Parameters:

node - the top node of a sub-tree about to be visited

Returns:

true if node's children should be visited before node, false otherwise

stopTraversal

public boolean stopTraversal()

Description copied from interface: Visitor

Method that is called to see if query tree traversal should be stopped before visiting all nodes. Useful for short circuiting traversal if we already know we are done.

Specified by:

stopTraversal in interface Visitor

Returns:

true/false