code: @Override
      public Comparable<?> getCompareValue(final AbstractUIField _uiField)
          throws EFapsException
      {
          Comparable<?> ret = null;
          for (final IComponentFactory factory : _uiField.getFactories().values()) {
              if (factory instanceof AbstractUIFactory) {
                  final AbstractUIFactory uiFactory = (AbstractUIFactory) factory;
                  if (uiFactory.applies(_uiField)) {
                      ret = uiFactory.getCompareValue(_uiField);
                      break;
                  }
              }
          }
          return ret;
      }
docs: {@inheritDoc}