net.sf.farrago.fennel.rel
Class FennelRenameRule

java.lang.Object
  extended by org.eigenbase.relopt.RelOptRule
      extended by net.sf.farrago.fennel.rel.FennelRenameRule
Direct Known Subclasses:
FennelInsertRenameRule

public class FennelRenameRule
extends RelOptRule

FennelRenameRule is a rule for converting a rename-only Project into FennelRename.

Version:
$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/FennelRenameRule.java#4 $
Author:
John V. Sichi

Field Summary
static FennelRenameRule instance
           
 
Fields inherited from class org.eigenbase.relopt.RelOptRule
ANY, description, operands
 
Constructor Summary
private FennelRenameRule()
          Creates a FennelRenameRule.
protected FennelRenameRule(RelOptRuleOperand operand)
          Creates a FennelRenameRule with an explicit root operand.
 
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.
protected  FennelRenameRel renameChild(ProjectRel project)
          If appropriate, creates a FennelRenameRel to replace an existing ProjectRel.
 
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

instance

public static final FennelRenameRule instance
Constructor Detail

FennelRenameRule

private FennelRenameRule()
Creates a FennelRenameRule.


FennelRenameRule

protected FennelRenameRule(RelOptRuleOperand operand)
Creates a FennelRenameRule with an explicit root operand.

Parameters:
operand - root operand, must not be null
Method Detail

getOutConvention

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

Overrides:
getOutConvention in class RelOptRule

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)

renameChild

protected FennelRenameRel renameChild(ProjectRel project)
If appropriate, creates a FennelRenameRel to replace an existing ProjectRel.

Parameters:
project - the existing ProjectRel
Returns:
the replacement FennelRenameRel or null if the project cannot be replaced with a FennelRenameRel