BasicOperator pre;
for (int i = 0; i < pres.size(); i++) {
pre = pres.get(i);
pre.addSucceedingOperator(new OperatorIDTuple(optional, 0));
pre.removeSucceedingOperator(genAdd);
optional.addPrecedingOperator(pre);
}
optional.removePrecedingOperator(genAdd);
optional.setSucceedingOperator(new OperatorIDTuple(genAdd, 0));