Class TraitMatchingRule

  extended by org.eigenbase.relopt.RelOptRule
      extended by org.eigenbase.rel.convert.TraitMatchingRule

public class TraitMatchingRule
extends RelOptRule

TraitMatchingRule adapts a converter rule, restricting it to fire only when its input already matches the expected output trait. This can be used with HepPlanner in cases where alternate implementations are available and it is desirable to minimize converters.

$Id: //open/dev/farrago/src/org/eigenbase/rel/convert/ $
John V. Sichi

Field Summary
private  ConverterRule converter
Fields inherited from class org.eigenbase.relopt.RelOptRule
ANY, description, operands
Constructor Summary
TraitMatchingRule(ConverterRule converterRule)
          Creates a new TraitMatchingRule.
Method Summary
 CallingConvention getOutConvention()
          Returns the calling convention of the result of firing this rule, null if not known.
 void onMatch(RelOptRuleCall call)
          Receives notification about a rule match.
Methods inherited from class org.eigenbase.relopt.RelOptRule
convert, equals, equals, getOperand, getOperands, getOutTrait, hashCode, matches, mergeTraitsAndConvert, mergeTraitsAndConvert, toString
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail


private final ConverterRule converter
Constructor Detail


public TraitMatchingRule(ConverterRule converterRule)
Creates a new TraitMatchingRule.

converterRule - rule to be restricted; rule must take a single operand expecting a single input
Method Detail


public CallingConvention getOutConvention()
Description copied from class: RelOptRule
Returns the calling convention of the result of firing this rule, null if not known.

getOutConvention in class RelOptRule


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: