@Override
 public List<Department> retrieveData() throws Exception {
   list_dpt.clear();
   list_Alldpt = AppContext.getInstance().getDepartmentService().getDepartments();
   List<Department> list_dt = list_Alldpt;
   if (this.getSelectionObj() == null) {
     list_dpt = (ArrayList<Department>) list_dt;
     return list_dt;
   } else {
     for (Department dpt : list_dt) {
       if (dpt.getParent() != null) {
         if (dpt.getParent().getId() == ((Department) getSelectionObj().getEntity()).getId()) {
           list_dpt.add(dpt);
         }
       }
       if (getSelectionObj().getId() == dpt.getId()) {
         list_dpt.add(0, dpt);
       }
     }
     return list_dpt;
   }
 }
 @Override
 public void update(Department t) {
   if (t.getParent() != null) {
     new DepartmentDialog(this.getViewSite().getShell(), t, t.getParent()).open();
   }
 }