Collection c = dataFields.values();
Iterator itr = c.iterator();
while (itr.hasNext()) {
dataField = (DataField)itr.next();
offset = dataField.pos();
length = dataField.length();
ObjectHelper.notNull(offset, "Position/offset is not defined for the field: " + dataField.toString());
ObjectHelper.notNull(offset, "Length is not defined for the field: " + dataField.toString());