org.eigenbase.rel.convert
Class TraitMatchingRule

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

public class TraitMatchingRule
extends RelOptRule

TraitMatchingRule adapts a converter rule, restricting it to fire only when its input already matches the expected output trait. This can be used with HepPlanner in cases where alternate implementations are available and it is desirable to minimize converters.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/convert/TraitMatchingRule.java#10 $

Author:

John V. Sichi

Field Summary

private ConverterRule

converter

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

TraitMatchingRule(ConverterRule converterRule)
Creates a new TraitMatchingRule.

Method Summary

CallingConvention	getOutConvention() Returns the calling convention of the result of firing this rule, null if not known.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

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

Methods inherited from class java.lang.Object

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

Field Detail

converter

private final ConverterRule converter

Constructor Detail

TraitMatchingRule

public TraitMatchingRule(ConverterRule converterRule)

Creates a new TraitMatchingRule.

Parameters:

converterRule - rule to be restricted; rule must take a single operand expecting a single input

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

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)