Easy to set object properties from strings?

Brief background: I have a servlet filter that handles authentication. It wants to auto-register previously unseen users, and update already-registered users, from information in cookies. The information is mostly in the form of strings, but the object's fields might not be. The question: Is there a simple, type-independent method to set an XWiki Object field's value from a string? The question is not "how can this be done", since I can easily work that out, but rather "is there a method currently available"? brain[sic]