private void createMaterialSelectItem() {
   try {
     ArrayList<Material> matList = matController.getMaterials(selectedMaterialGroup);
     materialSelectItemList.clear();
     materialSelectItemList.add(new SelectItem(Long.valueOf(-1), "àÅ×Í¡ÇÑÊ´Ø"));
     SelectItem selectItem;
     for (Material material : matList) {
       selectItem = new SelectItem(material.getId(), material.toString());
       materialSelectItemList.add(selectItem);
     }
   } catch (ControllerException e) {
     e.printStackTrace();
     FacesUtils.reportError(FacesContext.getCurrentInstance(), e.getMessage(), e.getMessage(), e);
   }
 }