Default Ship Method at sales order header using groovy

Summary:

hi Gurus,

I had the below DFF defined at customer ship to site level, FOB freight terms and warehouse are working. if we have to default shipping method do we need to define three DFF for Carrier , shipping mode and service or we cant default ship method at sales order header level.

I am using the below groovy logic for warehouse, FOB and freight terms. but extending the same for ship method is giving me errors

import oracle.apps.scm.doo.common.extensions.ValidationException;
import oracle.apps.scm.doo.common.extensions.Message;

String result2= header.getAttribute("FulfillmentOrganizationCode");
def TType = header.getAttribute("TransactionTypeCode");