final Union unionOp = new Union();
Operator testOP = (Operator) node.jjtGetChild(0).jjtAccept(this, data);
if (testOP != null)
unionOp.addSucceedingOperator(new OperatorIDTuple<Operator>(testOP, 0));
testOP = (Operator) node.jjtGetChild(1).jjtAccept(this, data);
if (testOP != null)
unionOp.addSucceedingOperator(new OperatorIDTuple<Operator>(testOP, 1));