org.eigenbase.rel.rules
Class ExtractJoinFilterRule

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

public final class ExtractJoinFilterRule
extends RelOptRule

Rule to convert an inner join to a filter on top of a cartesian inner join.

One benefit of this transformation is that after it, the join condition can be combined with conditions and expressions above the join. It also makes the FennelCartesianJoinRule applicable.

Since:

3 February, 2006

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/ExtractJoinFilterRule.java#2 $

Author:

jhyde

Field Summary

static ExtractJoinFilterRule

instance The singleton.

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

ExtractJoinFilterRule() Creates an ExtractJoinFilterRule.

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 ExtractJoinFilterRule instance

The singleton.

Constructor Detail

ExtractJoinFilterRule

private ExtractJoinFilterRule()

Creates an ExtractJoinFilterRule.

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)