vaughn vernon - implementing domain-driven design - ch 2

Does anyone know if there is a forum to discuss Vaughn's book?

I've just finished chapter 2 with a lingering question. I understand the example where User and Permission are not correct within the Collaboration Context, and that Author is more appropriate, moving User out to a separate Security Context. What I'm missing is how in the improved example the permission check is done. I can't find a call out to the Security Context checking if the User associated with the Author has permission to start a discussion. Should I assume that there is some kind of container checking this (just like the @Transactional is handled by a container)? I would be greatly against that, because that would bind a behavior aspect onto an (somewhat hidden) implementation; I'd rather have an explicit mention of the required permission behavior on Forum, or at least an explici
 t annotation @RequiresStartDiscussionPermission or something.

Furthermore, the permission to start a discussion seems like a cross cutting problem; either the Collaboration Context knows about security, or the Security Context knows about forums and discussions.

Thanks!

Tom





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