Since no one was answering to my post in the GSoC forum I'll try it here :-)
For OpenID support I implemented a DataObjectDecorator, but I couldn't figure out how I can add a custom validator to it. I need to ensure that the entered OpenID is unique so that only one user account is linked to a specific OpenID. Is that somehow possible?
At the moment I prevent duplicate OpenIDs by using a unique-index, but no error message will be shown.
Is there any way to implement a validator for DataObjectDecorators or handle such database errors ("Duplicate entry 'http://markus-lanthaler.myopenid.com/' for key 2")?
This would help me a lot to complete OpenID support!