net.sf.farrago.fennel.rel
Class WindowedAggSplitterRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      net.sf.farrago.fennel.rel.WindowedAggSplitterRule

public class WindowedAggSplitterRule
extends RelOptRule

Rule which slices the CalcRel into sections which contain windowed agg functions and sections which do not.

The sections which contain windowed agg functions become instances of WindowedAggregateRel. If the CalcRel does not contain any windowed agg functions, does nothing.

Since:

April 24, 2005

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/WindowedAggSplitterRule.java#1 $

Author:

Julian Hyde

Nested Class Summary

(package private) static class

WindowedAggSplitterRule.WindowedAggRelSplitter Splitter which distinguishes between windowed aggregation expressions (calls to RexOver) and ordinary expressions.

Field Summary

static WindowedAggSplitterRule

instance The singleton instance.

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private

WindowedAggSplitterRule() Creates a rule.

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 WindowedAggSplitterRule instance

The singleton instance.

Constructor Detail

WindowedAggSplitterRule

private WindowedAggSplitterRule()

Creates a rule.

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)