Class RemoveTrivialProjectRule


public class RemoveTrivialProjectRule
extends VolcanoRule

Rule which, given a ProjectRel node which merely returns its input, converts the node into its child.

For example, ProjectRel(ArrayReader(a), {$input0}) becomes ArrayReader(a).

Field Summary
Fields inherited from class net.sf.saffron.opt.VolcanoRule
description, planner
Constructor Summary
Method Summary
private static boolean isIdentity(RexNode[] exps, int fieldCount)
 void onMatch(VolcanoRuleCall call)
          This method is called every time the rule matches.
Methods inherited from class net.sf.saffron.opt.VolcanoRule
convert, getOutConvention, toString
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail


public RemoveTrivialProjectRule()
Method Detail


public void onMatch(VolcanoRuleCall call)
Description copied from class: VolcanoRule
This method is called every time the rule matches. 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 VolcanoRuleCall.transformTo(net.sf.saffron.rel.SaffronRel) to register the expression.

Specified by:
onMatch in class VolcanoRule


private static boolean isIdentity(RexNode[] exps,
                                  int fieldCount)