static Object getRequiredPrimitiveTypeValue(final Element element, final String attributeName, final Class valueClass) {
    final String str = getRequiredString(element, attributeName);
    try {
      final Method method = valueClass.getMethod("valueOf", String.class);
      return method.invoke(null, str);
    }
    catch (NumberFormatException e) {
      throw new IllegalArgumentException("attribute '" + attributeName + "' is not a proper float: " + str);
    }
    catch (Exception e) {
      throw new RuntimeException(e);
    }
  }
static Object getRequiredPrimitiveTypeValue(final Element element, final String attributeName, final Class valueClass)