org.eigenbase.rel.rules
Class PushProjectPastSetOpRule

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

public class PushProjectPastSetOpRule
extends RelOptRule

PushProjectPastSetOpRule implements the rule for pushing a ProjectRel past a SetOpRel. The children of the SetOpRel will project only the RexInputRefs referenced in the original ProjectRel.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/PushProjectPastSetOpRule.java#12 $

Author:

Zelaine Fong

Field Summary

static PushProjectPastSetOpRule	instance
private PushProjector.ExprCondition	preserveExprCondition Expressions that should be preserved in the projection

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private	PushProjectPastSetOpRule() Creates a PushProjectPastSetOpRule.
	PushProjectPastSetOpRule(PushProjector.ExprCondition preserveExprCondition) Creates a PushProjectPastSetOpRule with an explicit condition whether to preserve expressions.

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 PushProjectPastSetOpRule instance

preserveExprCondition

private PushProjector.ExprCondition preserveExprCondition

Expressions that should be preserved in the projection

Constructor Detail

PushProjectPastSetOpRule

private PushProjectPastSetOpRule()

Creates a PushProjectPastSetOpRule.

PushProjectPastSetOpRule

public PushProjectPastSetOpRule(PushProjector.ExprCondition preserveExprCondition)

Creates a PushProjectPastSetOpRule with an explicit condition whether to preserve expressions.

Parameters:

preserveExprCondition - Condition whether to preserve expressions

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)