LensKit precalculation dependency-injection structure.

uu-precalc.clj

(ns ...
  (:import [clojure.lang IDeref]
           ...)

(definterface UUPrecalc)

(defprovider uu-precalc
  ^UUPrecalc [^UserDAO udao, ^UserEventDAO uedao]
  (let [data ...]
    (reify UUPrecalc IDeref (deref [_] data))))

...

(defprovider suu-item-scorer
  ^ItemScorer [^UserEventDAO udao, ^ItemEventDAO idao, ^UUPrecalc precalc]
  ;; Use @precalc
  ...)

...

(defn configure-recommender
  ...
    (-> (.bind UUPrecalc) (.toProvider uu-precalc))
  ...)