I don't have an answer for you but this mailing list is a place where people discuss such things: http://cs.oswego.edu/pipermail/concurrency-interest/

Thanks

you can also use compare-and-swap! directly in clojure

Yeah, although I'm trying to not reimplement a concurrent queue in clojure with atoms

do you need the blocking behavior?

no, I just need to be able to do atomic removal of elements after I inspect them

(of BlockingQueues in j.u.concurrent)

then honestly I'd look at putting a PersistentQueue in an atom, and using cas, not swap

That might be feasible, the main reason I hadn't looked too hard at this is I'm expecting high contention on this queue and so I was looking to j.u.concurrent for mutable implementations to help mitigate that cost.

j.u.c queues don't allow you to atomically peek at the tail of a queue

yes, that was the problem