org.eigenbase.rel.convert
Class ConverterRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      org.eigenbase.rel.convert.ConverterRule

Direct Known Subclasses:

FactoryConverterRule, FennelCalcRule, FennelEmptyRule, FennelOneRowRule, FennelUnionRule, FennelValuesRule, IteratorToFennelConverter.IteratorToFennelPullRule, IterRules.IterCalcRule, IterRules.OneRowToIteratorRule, IterRules.UnionToIteratorRule, VolcanoPlannerTraitTest.AltTraitConverterRule, VolcanoPlannerTraitTest.PhysToIteratorConverterRule

public abstract class ConverterRule
extends RelOptRule

Abstract base class for a rule which converts from one calling convention to another without changing semantics.

Since:

May 5, 2003

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/convert/ConverterRule.java#16 $

Author:

jhyde

Nested Class Summary

private static class

ConverterRule.ConverterRelOptRuleOperand

Field Summary

private RelTrait	inTrait
private RelTrait	outTrait

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

ConverterRule(Class clazz, RelTrait in, RelTrait out, String description)
Creates a ConverterRule.

Method Summary

abstract RelNode	convert(RelNode rel)
RelTrait	getInTrait()
CallingConvention	getOutConvention() Returns the calling convention of the result of firing this rule, null if not known.
RelTrait	getOutTrait() Returns the trait which will be modified as a result of firing this rule, or null if the rule is not a converter rule.
RelTraitDef	getTraitDef()
boolean	isGuaranteed() Returns true if this rule can convert any relational expression of the input convention.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

convert, equals, equals, getOperand, getOperands, hashCode, matches, mergeTraitsAndConvert, mergeTraitsAndConvert, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

inTrait

private final RelTrait inTrait

outTrait

private final RelTrait outTrait

Constructor Detail

ConverterRule

public ConverterRule(Class clazz,
                     RelTrait in,
                     RelTrait out,
                     String description)

Creates a ConverterRule.

Parameters:

clazz - Type of relational expression to consider converting

in - Trait of relational expression to consider converting

out - Trait which is converted to

description - Description of rule

"Precondition:"

in != null, out != null

Method Detail

getOutConvention

public CallingConvention getOutConvention()

Description copied from class: RelOptRule

Returns the calling convention of the result of firing this rule, null if not known.

Overrides:

getOutConvention in class RelOptRule

getOutTrait

public RelTrait getOutTrait()

Description copied from class: RelOptRule

Returns the trait which will be modified as a result of firing this rule, or null if the rule is not a converter rule.

Overrides:

getOutTrait in class RelOptRule

getInTrait

public RelTrait getInTrait()

getTraitDef

public RelTraitDef getTraitDef()

convert

public abstract RelNode convert(RelNode rel)

isGuaranteed

public boolean isGuaranteed()

Returns true if this rule can convert any relational expression of the input convention.

The union-to-java converter, for example, is not guaranteed, because it only works on unions.

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back RelOptRuleCall.transformTo(org.eigenbase.rel.RelNode) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)