ref.clj

(set! *warn-on-reflection* true)

(defonce ref-ids (atom 0))

(declare ^java.util.concurrent.atomic.AtomicReferenceFieldUpdater ref-updater)

(deftype ARef [id
               ^:volatile-mutable value
               offers]
  clojure.lang.IDeref
  (deref [_]
    (loop [i 0]
      (let [v value]
        (if (identical? v not-defined)
          (do
            (Thread/sleep (Math/pow 2 i))
            (recur (inc i)))
          v))))
  clojure.lang.IFn
  (invoke [_]
    (java.util.concurrent.atomic.AtomicReferenceFieldUpdater/newUpdater
     ARef
     Object
     "value")))

(def ^java.util.concurrent.atomic.AtomicReferenceFieldUpdater ref-updater ((fn [] ((->ARef nil nil nil)))))

(defn ref-get [r]
  (.get ref-updater r))

(defn make-ref [init]
  (->ARef (swap! ref-ids inc)
          init
          (java.util.concurrent.LinkedBlockingQueue.)))