clojure - 如何使 java API 包装器与不同的函数参数一起工作？

Question

我正在为 Java API 编写一个小包装器，并创建一个像这样的侦听器

(defn conv-listener [f]
  (proxy [com.tulskiy.keymaster.common.HotKeyListener] [] (onHotKey [hotKey] (f))))

f无论函数接受 1 个参数还是零个参数，有没有一种方法可以让我完成这项工作。（即，如果f不接受参数，只需用 调用它(f)，如果它接受参数 - 在这种情况下将是热键的值 - 用 调用它(f hotKey)）？

Answer 1

不。只要(f hotKey)一直调用，如果有人想使用忽略的函数，hotKey那么他们可以传递类似(fn [_] (...do whatever...)).

Answer 2

这就是我们最终解决它的方式（来自 Nic Marsh 的拉取请求）：

(defn arg-count [function]
  "Counts the number of arguments the given function accepts"
  (let [method     (first (.getDeclaredMethods (class function)))
        parameters (.getParameterTypes method)]
    (alength parameters)))

(defn call-with-correct-args [function & args]
  "Call the given function on all given args that it can accept"
  (let [amount-accepted (arg-count function)
        accepted-args   (take amount-accepted args)]
    (apply function accepted-args)))

(defn- conv-listener [function]
  "Takes a function with one argument, which will get passed the keycode, and creates a listener"
  (proxy [com.tulskiy.keymaster.common.HotKeyListener] []
    (onHotKey [hotKey] (call-with-correct-args function hotKey))))

http://github.com/houshuang/keymaster-clj