Class WindowedAggSplitterRule

  extended by org.eigenbase.relopt.RelOptRule
      extended by 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.

April 24, 2005
$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/ $
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


public static final WindowedAggSplitterRule instance
The singleton instance.

Constructor Detail


private WindowedAggSplitterRule()
Creates a rule.

Method Detail


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
call - Rule call
See Also: