org.eigenbase.rel.rules
Class MergeCalcRule

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

public class MergeCalcRule
extends RelOptRule

Planner rule which merges a CalcRel onto a CalcRel. The resulting CalcRel has the same project list as the upper CalcRel, but expressed in terms of the lower CalcRel's inputs.

Since:

Mar 7, 2004

Version:

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

Author:

jhyde

Field Summary

static MergeCalcRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

MergeCalcRule()

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 MergeCalcRule instance

Constructor Detail

MergeCalcRule

private MergeCalcRule()

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)