cache.clj

(ns ^{:doc "clojure.core.cache implementation(s) on top of MongoDB."
      :author "Michael S. Klishin"}
  monger.cache
  (:require [monger.collection  :as mc]
            [clojure.core.cache :as cache])
  (:use monger.conversion)
  (:import [clojure.core.cache CacheProtocol]))

;;
;; Implementation
;;

(def ^{:const true}
  default-cache-collection "cache_entries")

;;
;; API
;;

(defrecord BasicMongerCache [collection])

(extend-protocol clojure.core.cache.CacheProtocol
  BasicMongerCache
  (lookup [c k]
    (mc/find-map-by-id (get c :collection) k))
  (lookup [c k not-found]
    (if-let [v (mc/find-map-by-id (get c :collection) k)]
      (:value v)
      not-found))
  (has? [c k]
    (mc/any? (get c :collection) {:_id key}))
  (hit [this k]
    this)
  (miss [c k v]
    (mc/insert (get c :collection) {:_id k :value v}))
  (evict [c k]
    (mc/remove-by-id (get c :collection) k))
  (seed [c m]
    (mc/insert-batch (get c :collection) (map (fn [[k v]]
                                                {:_id k :value v}) m))))


(defn basic-monger-cache-factory
  [coll base]
  (cache/seed (BasicMongerCache. collection) base))