[TYPO3-mvc] How to add a unique/primary key property to a manually created domain model?

[Jan Kornblum]

Hi group,

how can i add  "unique/primary/required"-like property to a manually 
created domain model. the model was not created using extensionbuilder 
and the model doesn't own a underlaying database.

The domain model extends AbstractEntity, and when i vardump the object 
i see that there is a uid, but it is NULL.

Do i have to implement the unique/primary/required logic myself or can 
this be done by any @validate oder similar notations?

Nice weelkend, Jan