com.lucidera.lcs
Class LcsRemoveRidExprRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      com.lucidera.lcs.LcsRemoveRidExprRule

public class LcsRemoveRidExprRule
extends RelOptRule

LcsRemoveRidExprRule is a rule for converting rid expressions that appear in a ProjectRel whose child is a EmptyRel into BIGINT null literals. Since the child of the project produces no rows, it doesn't matter what the rid expression returns, so long as the type of the constant matches the original type of the rid expression.

Version:

$Id: //open/dev/farrago/src/com/lucidera/lcs/LcsRemoveRidExprRule.java#6 $

Author:

Zelaine Fong

Nested Class Summary

private class

LcsRemoveRidExprRule.RidExprConverter Shuttle that locates rid expressions and converts them to literals with the value 0.

Field Summary

static LcsRemoveRidExprRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

LcsRemoveRidExprRule() Creates a LcsRemoveRidExprRule.

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 LcsRemoveRidExprRule instance

Constructor Detail

LcsRemoveRidExprRule

private LcsRemoveRidExprRule()

Creates a LcsRemoveRidExprRule.

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)