run po report from deafferents screen

public class NW_POController extends SrsReportRunController
{
    protected void preRunModifyContract()
    {
        NW_GeneralContract contract;
    
        VendPurchOrderJour table;
        PurchTable PO;
        if(!this.parmArgs().record())
            throw error("@SYS26348");
        else
        {
            if(this.parmArgs().record().TableId == tableNum(VendPurchOrderJour))
                table = this.parmArgs().record();
            if(this.parmArgs().record().TableId == tableNum(PurchTable))
                PO = this.parmArgs().record();
    
        }
        if (table)
        {
            contract = this.parmReportContract().parmRdpContract() as NW_GeneralContract;
            if (table)
                contract.parmRecordId(table.RecId);
        }
        if (PO)
        {
            contract = this.parmReportContract().parmRdpContract() as NW_GeneralContract;
            if (PO)
                contract.parmRecordId(PO.RecId);
        }
    }
  
  //------------------

//--   DP calss
public void processReport()
{
    NW_GeneralContract   contract;
    VendPurchOrderJour  VendPurchOrderJour;
    PurchTable          PurchTable;
    PurchLine           PurchLine;
    VendTable           VendTable;
    PurchTotals         purchTotals;
    HcmWorker           HcmWorker;
    PurchRFQReplyLinePurchLine      Reply;
    TaxItemGroupHeading             TaxItemGroup;
    TaxOnItem                       TaxOnItem;
    contract = this.parmDataContract() as NW_GeneralContract;

    select VendPurchOrderJour where VendPurchOrderJour.RecId==contract.parmRecordId();
    select PurchTable where PurchTable.PurchId == VendPurchOrderJour.PurchId;
    if(!VendPurchOrderJour)
        select PurchTable where PurchTable.RecId==contract.parmRecordId();
...