@Override
    public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx procCtx,
        Object... nodeOutputs) throws SemanticException {

      return null;
    }
Operator factory for the rule processors for inferring bucketing/sorting columns.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/BucketingSortingOpProcFactory.java