org.eigenbase.relopt
Interface RelImplementor

All Known Subinterfaces:

FennelRelImplementor

All Known Implementing Classes:

FarragoRelImplementor, JavaRelImplementor

public interface RelImplementor

Callback used to hold state while converting a tree of relational expressions into a plan. Calling conventions typically have their own protocol for walking over a tree, and correspondingly have their own implementors, which are subclasses of RelImplementor.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/relopt/RelImplementor.java#12 $

Method Summary

Object	visitChild(RelNode parent, int ordinal, RelNode child) Implements a relational expression according to a calling convention.
Object	visitChildInternal(RelNode child) Called from visitChild(org.eigenbase.rel.RelNode, int, org.eigenbase.rel.RelNode) after the frame has been set up.
Object	visitChildInternal(RelNode child, int ordinal) Called from visitChild(org.eigenbase.rel.RelNode, int, org.eigenbase.rel.RelNode) after the frame has been set up.

Method Detail

visitChild

Object visitChild(RelNode parent,
                  int ordinal,
                  RelNode child)

Implements a relational expression according to a calling convention.

Parameters:

parent - Parent relational expression

ordinal - Ordinal of child within its parent

child - Child relational expression

Returns:

Interpretation of the return value is left to the implementor

visitChildInternal

Object visitChildInternal(RelNode child)

Called from visitChild(org.eigenbase.rel.RelNode, int, org.eigenbase.rel.RelNode) after the frame has been set up. Specific implementors should override this method.

Parameters:

child - Child relational expression

Returns:

Interpretation of the return value is left to the implementor

visitChildInternal

Object visitChildInternal(RelNode child,
                          int ordinal)

Called from visitChild(org.eigenbase.rel.RelNode, int, org.eigenbase.rel.RelNode) after the frame has been set up. Specific implementors should override this method.

Parameters:

child - Child relational expression

ordinal - Ordinal of child within its parent

Returns:

Interpretation of the return value is left to the implementor