Packingslip duplicate control while posting packingslip

 [ExtensionOf(ClassStr(SalesPackingSlipJournalCreate))]

final class EEMCSalesPackingSlipJournalCreate_Extension

{

    protected void initJournalHeader()

    {

        CustPackingSlipJour         custPackingSlipJourLocal;

        CustParameters              custParameters  =   CustParameters::find();

        if(custParameters.EEMC_PackingSlipNonDuplicating == NoYes::Yes)

        {

            select custPackingSlipJourLocal where custPackingSlipJourLocal.PackingSlipId == this.getJournalNumber();

            if(custPackingSlipJourLocal)

            {

                throw error(strFmt("Packingslip Id : %1 can't be duplicated", custPackingSlipJourLocal.PackingSlipId));

            }

        }

        next initJournalHeader();

    }

}