joshjones

(defn ping-forever-core-async
  [host ms-pause]
  (let [termination-ch (chan)
        termination-fn #(put! termination-ch :die)]
    (go-loop [sleep-ch (timeout 0)]
      (let [[_ ch] (alts! [sleep-ch termination-ch])]
        (if (= ch sleep-ch)
          (do
            (println "Pinging" host)
            (recur (timeout ms-pause)))

joshjones

;;;;;;;;;;; STUBBING A FUNCTION

(defn select-id [id]
  ; real code would connect to db, just simulating here
  {:col1 (rand-int 101)
   :col2 (rand-nth ["Joe" "Bob" "Bill" "Sally"])})

(s/def ::col1 nat-int?)
(s/def ::col2 (s/with-gen string? #(gen/such-that (complement empty?) (gen/string-alphanumeric))))
(s/def ::db-row (s/keys :req-un [::col1 ::col2]))

joshjones

(import '[java.util.concurrent Callable
                               CountDownLatch
                               Executors
                               Semaphore
                               TimeUnit])

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Examples of creating and joining threads in clojure
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(let [numthreads 5