org.apache.derby.impl.sql.compile
Class ReplaceAggregatesWithCRVisitor

java.lang.Object
  org.apache.derby.impl.sql.compile.ReplaceAggregatesWithCRVisitor

All Implemented Interfaces:

Visitor

public class ReplaceAggregatesWithCRVisitor

extends java.lang.Object

implements Visitor

Replace all aggregates with result columns.

Author:

jamie

Field Summary

private ResultColumnList	rcl
private java.lang.Class	skipOverClass
private int	tableNumber

Constructor Summary

ReplaceAggregatesWithCRVisitor(ResultColumnList rcl, java.lang.Class nodeToSkip)
Replace all aggregates with column references.

ReplaceAggregatesWithCRVisitor(ResultColumnList rcl, int tableNumber)
Replace all aggregates with column references.

Method Summary

boolean	skipChildren(Visitable node) Don't visit childen under the skipOverClass node, if it isn't null.
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 an aggregate node.

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

ReplaceAggregatesWithCRVisitor

public ReplaceAggregatesWithCRVisitor(ResultColumnList rcl,
                                      int tableNumber)

Replace all aggregates with column references. Add the reference to the RCL. Delegates most work to AggregateNode.replaceAggregatesWithColumnReferences(rcl, tableNumber).

Parameters:

rcl - the result column list

tableNumber - The tableNumber for the new CRs

ReplaceAggregatesWithCRVisitor

public ReplaceAggregatesWithCRVisitor(ResultColumnList rcl,
                                      java.lang.Class nodeToSkip)

Replace all aggregates with column references. Add the reference to the RCL. Delegates most work to AggregateNode.replaceAggregatesWithColumnReferences(rcl). Doesn't traverse below the passed in class.

Parameters:

rcl - the result column list

nodeToSkip - don't examine anything below nodeToSkip

Method Detail

visit

public Visitable visit(Visitable node)
                throws StandardException

Don't do anything unless we have an aggregate 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)

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

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

true/false

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