sleeping-thread.clj

(def open-for-discussion? (atom true))
(def discussion-count (agent 0))
(def discussion-board (ref []))
(def discussion-board-count 3)

(defn open-discussion [duration]
(do (Thread/sleep duration) (swap! open-for-discussion? not)))

(defn add-discussion []
(future
(while @open-for-discussion?
(println "discussion-board: " @discussion-board-count)
(dosync
(< (count (ensure discussion-board)) discussion-board-count)
(alter discussion-board conj :board-member)))
(Thread/sleep (+ 5 (rand-int 21)))))

(defn get-next-discussion []
(dosync
(let [next-dicussion (first (ensure discussion-board))]
(when next-discussion (alter discussion-board rest) next-discussion))))

(defn get-submission []
(future
(while @open-for-dicussion?
(when-let [next-discussion (get-next-discussion)]
(Thread/sleep 20)
(send discussion-count inc)))))

(do
(get-submission)
(add-discussion)

  (println "Open discussion board for 10 minutes")
  (open-discussion 10000)
  (println "Number of Posts: " @discussion-count)
  (System/exit 0))