net.sf.saffron.opt
Class RelImplementor.Translator

java.lang.Object
  |
  +--net.sf.saffron.opt.RelImplementor.Translator

Enclosing class:

RelImplementor

private static class RelImplementor.Translator

extends Object

Translator is a shuttle used to implement RelImplementor.translate(net.sf.saffron.rel.SaffronRel, net.sf.saffron.rex.RexNode).

Nested Class Summary

private static class

RelImplementor.Translator.WhichInputResult Result of call to whichInput(int, net.sf.saffron.rel.SaffronRel), contains the input relational expression, its index, and the index of the field within that relational expression.

Field Summary

(package private) RelImplementor	implementor
(package private) SaffronRel	rel

Constructor Summary

(package private)

RelImplementor.Translator(RelImplementor implementor, SaffronRel rel)

Method Summary

private Expression	convertCall(RexCall call, Expression[] operands)
Expression	go(RexNode rex)
private static RelImplementor.Translator.WhichInputResult	whichInput(int fieldIndex, SaffronRel rel) Returns the ordinal of the input relational expression which a given column ordinal comes from.

Methods inherited from class java.lang.Object

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

Field Detail

implementor

RelImplementor implementor

rel

SaffronRel rel

Constructor Detail

RelImplementor.Translator

RelImplementor.Translator(RelImplementor implementor,
                          SaffronRel rel)

Method Detail

go

public Expression go(RexNode rex)

whichInput

private static RelImplementor.Translator.WhichInputResult whichInput(int fieldIndex,
                                                                     SaffronRel rel)

Returns the ordinal of the input relational expression which a given column ordinal comes from.

For example, if rel has inputs I(a, b, c) and J(d, e), then whichInput(0, rel) returns 0 (column a), whichInput(2, rel) returns 0 (column c), whichInput(3, rel) returns 1 (column d).

Parameters:

fieldIndex - Index of field

rel - Relational expression

Returns:

a RelImplementor.Translator.WhichInputResult if found, otherwise null.

convertCall

private Expression convertCall(RexCall call,
                               Expression[] operands)