org.eigenbase.rel.rules
Class CombineUnionsRule

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

public class CombineUnionsRule
extends RelOptRule

CombineUnionsRule implements the rule for combining two non-distinct UnionRels into a single UnionRel.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/CombineUnionsRule.java#7 $

Author:

Zelaine Fong

Field Summary

static CombineUnionsRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

CombineUnionsRule() Creates a CombineUnionsRule.

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 CombineUnionsRule instance

Constructor Detail

CombineUnionsRule

private CombineUnionsRule()

Creates a CombineUnionsRule.

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)