Class ReplaceWindowFuncCallsWithCRVisitor

java.lang.Object

org.apache.derby.impl.sql.compile.ReplaceWindowFuncCallsWithCRVisitor

All Implemented Interfaces:

Visitor

class ReplaceWindowFuncCallsWithCRVisitor
extends Object
implements Visitor

Replace all window function calls with result columns.

Field Summary

Fields

Modifier and Type	Field	Description
private ResultColumnList	rcl
private Class<?>	skipOverClass
private int	tableNumber

Constructor Summary

Constructors

Constructor	Description
ReplaceWindowFuncCallsWithCRVisitor(ResultColumnList rcl, int tableNumber, Class<?> skipOverClass)	Replace all window function calls with column references.

Method Summary

Modifier and Type	Method	Description
boolean	skipChildren(Visitable node)	Don't visit children under the skipOverClass node, if it isn't null.
boolean	stopTraversal()	Visitor override.
Visitable	visit(Visitable node)	Don't do anything unless we have a window function node node.
boolean	visitChildrenFirst(Visitable node)	Visitor override.

Methods inherited from class Object

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

Field Details

rcl

private ResultColumnList rcl

skipOverClass

private Class<?> skipOverClass

tableNumber

private int tableNumber

Constructor Details

ReplaceWindowFuncCallsWithCRVisitor

ReplaceWindowFuncCallsWithCRVisitor(ResultColumnList rcl,
 int tableNumber,
 Class<?> skipOverClass)

Replace all window function calls with column references. Add the reference to the RCL. Delegates most work to WindowFunctionNode.replaceCallsWithColumnReferences(rcl, tableNumber).

Parameters:

rcl - the result column list

tableNumber - The tableNumber for the new CRs

skipOverClass - Don't go past this

Method Details

visit

public Visitable visit(Visitable node)
                throws StandardException

Don't do anything unless we have a window function node node. Visitor override.

Specified by:

visit in interface Visitor

Parameters:

node - the node to process

Returns:

a query tree node. Often times this is the same node that was passed in, but Visitors that replace nodes with other nodes will use this to return the new replacement node.

Throws:

StandardException - may be throw an error as needed by the visitor (i.e. may be a normal error if a particular node is found, e.g. if checking a group by, we don't expect to find any ColumnReferences that aren't under an AggregateNode -- the easiest thing to do is just throw an error when we find the questionable node).

See Also:

• Visitor.visit(Visitable)

skipChildren

public boolean skipChildren(Visitable node)

Don't visit children under the skipOverClass node, if it isn't null. Visitor override.

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

true/false

See Also:

• Visitor.skipChildren(Visitable)

visitChildrenFirst

public boolean visitChildrenFirst(Visitable node)

Visitor override.

Specified by:

visitChildrenFirst in interface Visitor

Parameters:

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

Returns:

false

See Also:

• Visitor.visitChildrenFirst(Visitable)

stopTraversal

public boolean stopTraversal()

Visitor override.

Specified by:

stopTraversal in interface Visitor

Returns:

false

See Also:

• Visitor.skipChildren(Visitable)