agent-validator.clj

(defn random-number [_]
  (rand-int 22))

(defn a-validate [valor]
  (> valor 10))

(defn a-errorhandler [ag ex]
  (println "Error: " (.getMessage ex)))

(defn a-watcher [ref chave antigo novo]
  (println "Watching:" ref chave antigo novo))

(def a (agent 11 :validator a-validate :error-handler a-errorhandler :error-mode :fail))

(add-watch a :watcher-1 a-watcher)