Generating identities for entities in DDD

Question

Edit

To further clarify my initial problem, I rewrote the question with more \'DDD\'-termini, common patterns and discussion arguments. The orginal version can be

Answer 1

I would place it in a factory. Generating id shouldn't be a part of domain logic in my opinion, because it's really an infrastructure matter. You can take id from DB or generate it with uuid or whatever. It's a detail. Also remember that only interface of a factory belongs to domain layer, not its implementation.

About your doubts for factory, if you use factory to create entities then you should use it everywhere. This is how I do it.

Answer 2

Vaughn Vernon author of Implementing Domain Driven Design advocates creating unique ids in repositories like this:

   public TenantId nextIdentity() {
        return new TenantId(UUID.randomUUID().toString().toUpperCase());
    }

TenantId is a value object that wraps the identity of the Entity.