TextItem: how to distinguish empty value and "null" string value?

[serge_hid]

1. SmartGWT 3.1 LGPL.
2. All browsers.

I have several TextItems on a DynamicForm. Their values are sent via POST-parameters (RestDataSource).

The problem is that "null" is sent in two cases:

1. TextItem is empty.
2. A user typed in "null" value (valid string value).

As a result, on the server side it is not possible to distinguish them. Is there anyway to determine if a TextItem was empty or a user explicitly typed in "null" value?

Thanks.

[serge_hid]

Anybody knows if it can be solved at all?

If it is not possible, it will also count as an answer (even though it would be strange).

P.S. I found this question asked in several threads but there's no clear answer in any of them.

[serge_hid]

Guys, can anybody help?

P.S. Maybe my question is not clear enough. If it is so, please let me know.