org.eigenbase.rel.rules
Class FilterToCalcRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      org.eigenbase.rel.rules.FilterToCalcRule

public class FilterToCalcRule
extends RelOptRule

Planner rule which converts a FilterRel to a CalcRel.

The rule does NOT fire if the child is a FilterRel or a ProjectRel (we assume they they will be converted using FilterToCalcRule or ProjectToCalcRule) or a CalcRel. This FilterRel will eventually be converted by MergeFilterOntoCalcRule.

Since:

Mar 7, 2004

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/FilterToCalcRule.java#1 $

Author:

jhyde

Field Summary

static FilterToCalcRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

FilterToCalcRule()

Method Summary

void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

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

Methods inherited from class java.lang.Object

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

Field Detail

instance

public static final FilterToCalcRule instance

Constructor Detail

FilterToCalcRule

private FilterToCalcRule()

Method Detail

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)