final OptimizerNode n;
// create a node for the operator (or sink or source) if we have not been here before
if (c instanceof GenericDataSinkBase) {
DataSinkNode dsn = new DataSinkNode((GenericDataSinkBase<?>) c);
this.sinks.add(dsn);
n = dsn;
}
else if (c instanceof GenericDataSourceBase) {
DataSourceNode dsn = new DataSourceNode((GenericDataSourceBase<?, ?>) c);