✨ Improve dispatcher impl usability.

backend/src/uxbox/util/dispatcher.clj

@@ -16,9 +16,9 @@
    [uxbox.util.spec :as us]
    [uxbox.util.exceptions :as ex])
   (:import
+   clojure.lang.IDeref
+   clojure.lang.MapEntry
    java.util.Map
-   java.util.List
-   java.util.Map$Entry
    java.util.HashMap))
 
 (definterface IDispatcher
@@ -27,9 +27,15 @@
 (deftype Dispatcher [reg attr interceptors]
   IDispatcher
   (add [this key f metadata]
-    (.put ^Map reg key (Map/entry f metadata))
+    (.put ^Map reg key (MapEntry/create f metadata))
     nil)
 
+  clojure.lang.IDeref
+  (deref [_]
+    {:registry reg
+     :attr attr
+     :interceptors interceptors})
+
   clojure.lang.IFn
   (invoke [_ params]
     (let [key (get params attr)
@@ -38,8 +44,8 @@
         (p/rejected (ex/error :type :not-found
                               :code :method-not-found
                               :hint "No method found for the current request."))
-        (let [f (.getKey ^Map$Entry entry)
-              m (.getValue ^Map$Entry entry)
+        (let [f (.key ^MapEntry entry)
+              m (.val ^MapEntry entry)
               d (p/deferred)]
 
           (sp/execute (conj interceptors f)
@@ -57,25 +63,53 @@
   `(defonce ~sname (Dispatcher. (HashMap.)
                                 ~dispatch-by
                                 ~interceptors)))
+(defn parse-defmethod
+  [args]
+  (loop [r {}
+         s 0
+         v (first args)
+         n (rest args)]
+    (case s
+      0 (if (symbol? v)
+          (recur (assoc r :sym v) 1 (first n) (rest n))
+          (throw (ex-info "first arg to `defmethod` should be a symbol" {})))
+      1 (if (qualified-keyword? v)
+          (recur (-> r
+                     (assoc :key (keyword (name v)))
+                     (assoc :meta {:spec v :doc nil}))
+                 3 (first n) (rest n))
+          (recur r (inc s) v n))
+      2  (if (simple-keyword? v)
+          (recur (-> r
+                     (assoc :key v)
+                     (assoc :meta {:doc nil}))
+                 3 (first n) (rest n))
+          (throw (ex-info "second arg to `defmethod` should be a keyword" {})))
+      3 (if (string? v)
+          (recur (update r :meta assoc :doc v) (inc s) (first n) (rest n))
+          (recur r 4 v n))
+      4 (if (map? v)
+          (recur (update r :meta merge v) (inc s) (first n) (rest n))
+          (recur r 5 v n))
+      5 (if (vector? v)
+          (assoc r :args v :body n)
+          (throw (ex-info "missing arguments vector" {}))))))
 
 (defmacro defmethod
-  [sname key metadata args & rest]
-  (s/assert symbol? sname)
-  (s/assert keyword? key)
-  (s/assert map? metadata)
-  (s/assert vector? args)
-  (let [f `(fn ~args ~@rest)]
+  [& args]
+  (let [{:keys [key meta sym args body]} (parse-defmethod args)
+        f `(fn ~args ~@body)]
     `(do
-       (s/assert dispatcher? ~sname)
-       (.add ~sname ~key ~f ~metadata)
-       ~sname)))
+       (s/assert dispatcher? ~sym)
+       (.add ~sym ~key ~f ~meta)
+       ~sym)))
 
 (def spec-interceptor
   "An interceptor that conforms the request with the user provided
   spec."
   {:enter (fn [{:keys [request] :as data}]
             (let [{:keys [spec]} (meta request)]
-              (if spec
+              (if-let [spec (s/get-spec spec)]
                 (let [result (s/conform spec request)]
                   (if (not= result ::s/invalid)
                     (assoc data :request result)