org.apache.derby.impl.sql.compile

Class ReplaceWindowFuncCallsWithCRVisitor

java.lang.Object

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

All Implemented Interfaces:

Visitor

public class ReplaceWindowFuncCallsWithCRVisitor
extends java.lang.Object
implements Visitor

Replace all window function calls with result columns.

Field Summary

Fields

Modifier and Type	Field and Description
private ResultColumnList	rcl
private java.lang.Class	skipOverClass
private int	tableNumber

Constructor Summary

Constructors

Constructor and Description
ReplaceWindowFuncCallsWithCRVisitor(ResultColumnList rcl, int tableNumber, java.lang.Class skipOverClass) Replace all window function calls with column references.

Method Summary

Methods

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

Methods inherited from class java.lang.Object

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

Field Detail

rcl

private ResultColumnList rcl

skipOverClass

private java.lang.Class skipOverClass

tableNumber

private int tableNumber

Constructor Detail

ReplaceWindowFuncCallsWithCRVisitor

public ReplaceWindowFuncCallsWithCRVisitor(ResultColumnList rcl,
                                   int tableNumber,
                                   java.lang.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 Detail

visit

public Visitable visit(Visitable node)
                throws StandardException

Don't do anything unless we have a window function node node. Vistor 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(org.apache.derby.iapi.sql.compile.Visitable)

skipChildren

public boolean skipChildren(Visitable node)

Don't visit childen under the skipOverClass node, if it isn't null. Vistor override.

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

true/false

See Also:

Visitor.skipChildren(org.apache.derby.iapi.sql.compile.Visitable)

visitChildrenFirst

public boolean visitChildrenFirst(Visitable node)

Vistor 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(org.apache.derby.iapi.sql.compile.Visitable)

stopTraversal

public boolean stopTraversal()

Vistor override.

Specified by:

stopTraversal in interface Visitor

Returns:

false

See Also:

Visitor.skipChildren(org.apache.derby.iapi.sql.compile.Visitable)