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@@ -60,6 +60,9 @@ A separation of concerns model for use on all platforms.
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We use a custom lifecycle dispatcher that uses multimethods, as suggested by the author's documentation.
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+Actually this style [is much slower](http://insideclojure.org/2015/04/27/poly-perf/) than Protocol based dispatch,
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+but very nice to work with.
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+
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```clojure
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(ns my.component
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(:require [clojure.tools.logging :refer [debugf infof]
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@@ -70,66 +73,52 @@ We use a custom lifecycle dispatcher that uses multimethods, as suggested by the
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; namespaced keywords for dispatch
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; (when (= *ns* 'my.component) (= ::my-message :my.component/my-message))
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-(defmethod react :component/start [c]
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+(defmethod react :component/start [component]
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(debugf "Starting my.component"))
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-(defmethod react :component/stop [c]
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+(defmethod react :component/stop [component]
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(debugf "Stopping my.component"))
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-(defmethod react ::my-message [c msg]
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- (infof "Got a message, what are we going to do about it? %s" msg))
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+(defmethod react ::my-message [component event]
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+ (infof "Got a event, what are we going to do about it? %s" event))
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; alternative syntax (experimental)
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(react-to ::my-message [event]
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- (infof "Got a message, what are we going to do about it? %s" msg))
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-```
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-
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-
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+ (infof "Got an event, what are we going to do about it? %s" event))
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```
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-(defmacro defupon
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- ""
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- [command & body]
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- (let [react-symbol (symbol (str *ns*) "upon")
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- react-multi `(defmulti ~react-symbol #(:component/event %2))]
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- `(do
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- (when-not ~(find-var react-symbol)
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- (println "Defining default react dispatcher: ")
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- ~react-multi)
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- (defmethod ~react-symbol ~command [~'component ~'event]
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- ~@body))))
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+A comparable protocol-based approach loses some of its niceness, but may win in dispatch speed. A macro could be constructed
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+to use an in-memory map based dispatch (ie. constant lookup time).
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-(let [say-reactor '(defupon :say
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- (format "say with component=%s, event=%s" component event))]
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- (println (macroexpand-1 say-reactor))
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- (eval say-reactor))
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-
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-(let [component {:name :my.component}
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- event {:component/event :say
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- :message "hi"}]
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- (upon component event))
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-
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+```clojure
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+(ns my.component
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+ (:require [clojure.tools.logging :refer [debugf infof]
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+ [component :refer [event-key Lifecycle]]))
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+
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+(defrecord Reactor [dispatch]
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+ Lifecycle
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+ (start [component]
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+ (debugf "Starting my.component"))
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+ (stop [component]
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+ (debugf "Stopping my.component"))
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+
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+ React
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+ (react [component event]
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+ (when-let [handler (get dispatch (event-key event))]
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+ (handler component event))))
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-```
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-```
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+(defn- my-message [component event]
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+ (infof "Got an event, what are we going to do about it? %s" event)
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-(defmacro defaction
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- ""
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- [command & body]
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- `(let [react-symbol# ~(find-var (symbol (str *ns*) "react"))]
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- (when-not react-symbol#
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- (println "Defining default react dispatcher")
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- (defmulti ~'react-symbol# #(:command %2)))
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- (defmethod react-symbol# ~command [~'component ~'event]
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- ~@body)))
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+(def component (->Reactor {::my-message my-message}))
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+;(react component event)
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```
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-
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### Marathon deployment
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Deploy non-Docker packages. Nothing in particular against Docker, but I don't see the case for it with Marathon
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Harlan Iverson