object_queue.clj

(def queue-size 30)

(defn make-object []
  (.. some object ..))
  
(defn build-queue [_]
  (let [block-queue (LinkedBlockingQueue. (int queue-size))]
    (do
      (repeat queue-size (.put block-queue (make-object)))
      block-queue)))

(def queue (atom build-queue))

(defn take-one []
  (.take @queue))

(defn put-back [ob]
  (.put @queue ob))

(defmacro with-shared-object
  [object & body]
  `(let [~object (take-one)]
      (try
        (let [res# ~@body]
          (put-back ~object)
          res#)
      (catch Throwable e#
        (put-back ~object)
        (throw e#)))))

;; Usage
(with-shared-object object
  (some-operation object))