PurchreqTable form Itemid lookup customization

// -- req is based on department item id lookup want to display related to the department selected


public void lookup()
{
    QueryBuildDataSource                    qbdsInventTable, qbdsEcoResCategory, qbdsEcoResProductCategoryExpanded, qbdsEcoResProcurementCategoryExpanded;
    QueryBuildRange                         qbr;
    Query                                   query   = new Query();
 
    EcoResCategory                          ecoResCategory;
    EcoResProductCategoryExpanded           ecoResProductCategoryExpanded;// view
    EcoResProcurementCategoryExpanded       ecoResProcurementCategoryExpanded;//view
    PurchReqLine                            _purchReqLine;
    Str60                                   departmentvalue , departmentText;
    DimensionAttributeValueSet              dimAttrValueSet;
    DimensionAttributeValueSetItem          dimAttrValueSetItem;
    DimensionAttributeValue                 dimAttrValue;
    DimensionAttribute                      dimAttr;
    Common                                  dimensionValueEntity;
    DimensionValue                          dimensionvalue;
    DimensionAliasName                      dimensionname;
    str                                     procurrentCategory;

      SysTablelookup              sysTableLookup  = SysTableLookup::newParameters(tablenum(InventTable), this);
 
 
     dimAttrValueSet = DimensionAttributeValueSet::find(PurchReqLine.DefaultDimension);

     while  select dimAttrValueSetItem
             where   dimAttrValueSetItem.DimensionAttributeValueSet == dimAttrValueSet.RecId
           {

                 dimAttrValue         = DimensionAttributeValue::find(dimAttrValueSetItem.DimensionAttributeValue);

                 dimAttr              = DimensionAttribute::find(dimAttrValue.DimensionAttribute);

                 dimensionValueEntity = DimensionDefaultingControllerBase::findBackingEntityInstance(curext(),dimAttr,dimAttrValue.EntityInstance);

                 if(dimAttr.Name == 'Department')
                 departmentvalue = dimAttrValue.getName();
                 //info(departmentvalue);
           }

          departmentText = departmentvalue;

    if(departmentText == 'Information and communications technology Department')
    {
             
        sysTableLookup.addLookupfield(fieldnum(InventTable, ItemId));
        sysTableLookup.addLookupfield(fieldnum(InventTable, NameAlias));
        sysTableLookup.addLookupfield(fieldnum(InventTable, ItemType));
        sysTableLookup.addLookupfield(fieldnum(InventTable, Product));

        qbdsInventTable = query.addDataSource(tableNum(InventTable));

        qbdsEcoResCategory = qbdsInventTable.addDataSource(tableNum(EcoResProductCategoryExpanded));
        qbdsEcoResCategory.relations(false);
        qbdsEcoResCategory.joinMode(joinMode::ExistsJoin);
        qbdsEcoResCategory.addLink(fieldNum(InventTable, ItemId), fieldNum(EcoResProductCategoryExpanded, ItemId));

        qbdsEcoResProcurementCategoryExpanded = qbdsEcoResCategory.addDataSource(tableNum(EcoResProcurementCategoryExpanded));
        qbdsEcoResProcurementCategoryExpanded.relations(false);
        qbdsEcoResProcurementCategoryExpanded.joinMode(joinMode::ExistsJoin);
             
        qbdsEcoResProcurementCategoryExpanded.addLink(fieldNum(EcoResProductCategoryExpanded,RecIdCategory ), fieldNum(EcoResProcurementCategoryExpanded,RecId));
     
        qbdsEcoResProcurementCategoryExpanded.addRange(fieldNum(EcoResProcurementCategoryExpanded, Name)).value("Water");

        sysTableLookup.parmQuery(query);
        sysTableLookup.performFormLookup();

    }
 
    if(departmentText == 'Laundry')
    {
             
        sysTableLookup.addLookupfield(fieldnum(InventTable, ItemId));
        sysTableLookup.addLookupfield(fieldnum(InventTable, NameAlias));
        sysTableLookup.addLookupfield(fieldnum(InventTable, ItemType));
        sysTableLookup.addLookupfield(fieldnum(InventTable, Product));

        qbdsInventTable = query.addDataSource(tableNum(InventTable));

        qbdsEcoResCategory = qbdsInventTable.addDataSource(tableNum(EcoResProductCategoryExpanded));
        qbdsEcoResCategory.relations(false);
        qbdsEcoResCategory.joinMode(joinMode::ExistsJoin);
        qbdsEcoResCategory.addLink(fieldNum(InventTable, ItemId), fieldNum(EcoResProductCategoryExpanded, ItemId));

        qbdsEcoResProcurementCategoryExpanded = qbdsEcoResCategory.addDataSource(tableNum(EcoResProcurementCategoryExpanded));
        qbdsEcoResProcurementCategoryExpanded.relations(false);
        qbdsEcoResProcurementCategoryExpanded.joinMode(joinMode::ExistsJoin);
             
        qbdsEcoResProcurementCategoryExpanded.addLink(fieldNum(EcoResProductCategoryExpanded,RecIdCategory ), fieldNum(EcoResProcurementCategoryExpanded,RecId));
     
        qbdsEcoResProcurementCategoryExpanded.addRange(fieldNum(EcoResProcurementCategoryExpanded, Name)).value("Clothes");
        qbdsEcoResProcurementCategoryExpanded.addRange(fieldNum(EcoResProcurementCategoryExpanded, Name)).value("Water");
        sysTableLookup.parmQuery(query);
        sysTableLookup.performFormLookup();

    }
}