return index;
}
@Override
public void createEmptyIndexScanSubmittingQueryResultWithOneEmptyBindingsAndConnectWithRoot(final OperatorIDTuple opID, final Item graphConstraint) {
this.root.getSucceedingOperators().add(new OperatorIDTuple(new EmptyIndexScanSubmittingQueryResultWithOneEmptyBindings(opID, graphConstraint, this.root), 0));
}