org.eigenbase.rel.rules
Class MergeProjectOntoCalcRule

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

public class MergeProjectOntoCalcRule
extends RelOptRule

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

Since:

Mar 7, 2004

Version:

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

Author:

jhyde

See Also:

MergeFilterOntoCalcRule

Field Summary

static MergeProjectOntoCalcRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

MergeProjectOntoCalcRule()

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 MergeProjectOntoCalcRule instance

Constructor Detail

MergeProjectOntoCalcRule

private MergeProjectOntoCalcRule()

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)