![WAIT...
Let's see if we can attach another crucial part
Executed function:
(defn attach-command-listener! []
(condensator/on c "command"
(fn [{data :data}]
(case data
"right" (right-sound)
"left" (left-sound)
nil))
{:address address :port port}))](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-4-320.jpg)
![API
(defn create
"Creates condensator based on meltdown or tcp capable condensator"
([address port])
([]))
(defn notify
"Notifies condensator with payload based on selector"
([condensator selector payload])
([selector payload {:keys [address port]}]))
(defn on
"Attaches listener to condensator"
([condensator selector cb])
([condensator selector cb {:keys [address port]}]))
(defn receive-event [condensator selector cb])
(defn send-event [condensator selector data cb])](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-11-320.jpg)
![(let [calculator (FooCalculator.)
inputBean (doto (InputBean.)
(.setFoo (Integer. 1))
(.setBar (Integer. 2))
(.setBaz (Integer. 3)))]
(.setInput calculator inputBean)
(.performCalculation calculator)
(let [resultBean (.getCalculationResultBean calculator)
subresultA (.getSubresultA resultBean)
subresultB (.getSubresultB resultBean)]
;; Do something with the result
))](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-15-320.jpg)
![(let [{:keys [subresult-a subresult-b]} (calc {:foo 1 :bar 2 :baz 3})]
;; Do something with the result
)](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-16-320.jpg)
![RANDOM LEARNINGS CONTINUED
Wrapping Java to Clojure is pretty much controlling mutability
and restricting state
(def c (condensator/create))
...
(condensator/on c "command" (fn [{data :data}] ...)
Restrict mutable java to one instance, pass it with immutable
data to clojure API](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-18-320.jpg)
![RANDOM LEARNINGS CONTINUED
#2
Testing asynchronous stuff is surprisingly simple with
promises
(it "remote notifies and locally executes listener"
(let [datapromise (promise)]
(condensator/on server "remote"
(fn [data]
(info datapromise)
(deliver datapromise (:data data))))
(tcp/send-tcp-msg
:port 3030,
:operation :notify,
:selector "remote",
:data "from-remote")
(let [result (deref datapromise 3000 nil)]
(should= "from-remote" result))))
A daily dose of Clojure increases programmer happiness by
63%](https://image.slidesharecdn.com/wrappingjavainawesomenessakacondensator-141126141414-conversion-gate01/85/Wrapping-java-in-awesomeness-aka-condensator-19-320.jpg)
Wrapping java in awesomeness aka condensator
- 1. WRAPPING JAVA IN AWESOMENESS CONDENSATOR REACTIVE COMMUNICATION OVER TCP
- 2. TERO KADENIUS (@PISKETTI) Clojure enthusiast, recovering Java programmer JUHA HEIMONEN (@EVILBUBU) Clojure N00b We are part of Flowa (@FlowaWolf)
- 3. FIRST THINGS FIRST Infrastructure of what you currently see
- 4. WAIT... Let's see if we can attach another crucial part Executed function: (defn attach-command-listener! [] (condensator/on c "command" (fn [{data :data}] (case data "right" (right-sound) "left" (left-sound) nil)) {:address address :port port}))
- 5. NOW IT IS LIKE THIS. New Infrastructure view
- 7. WE CAN SEND MESSAGES OTHER WAY AROUND
- 8. WHAT? Condensator = Spring Reactor (Java) Meltdown (Awesome Clojure by Clojurewerkz)
- 9. CONDENSATOR CONTAINS TCP messaging capability on top of Spring Reactor and Meltdown (by Clojurewerkz). So in overall, you get a system that implements Reactor pattern with TCP transport.
- 10. REACTOR PATTERN Event handling pattern Synchronous dispatching of events (Executes when it's possible to do so without blocking) Coarserly concurrent, doesn't use multiple threads
- 11. API (defn create "Creates condensator based on meltdown or tcp capable condensator" ([address port]) ([])) (defn notify "Notifies condensator with payload based on selector" ([condensator selector payload]) ([selector payload {:keys [address port]}])) (defn on "Attaches listener to condensator" ([condensator selector cb]) ([condensator selector cb {:keys [address port]}])) (defn receive-event [condensator selector cb]) (defn send-event [condensator selector data cb])
- 12. WHY BUILD ON TOP OF A JAVA LIBRARY?
- 13. NO NEED TO REINVENT THE WHEEL THERE ARE A LOT OF STUFF WRITTEN IN JAVA ALREADY MATURITY - QUITE A BIT OF JAVA STUFF IS BATTLE TESTED FOR YOU
- 14. USING A JAVA LIBRARY DIRECTLY CAN BE A BIT...
- 15. (let [calculator (FooCalculator.) inputBean (doto (InputBean.) (.setFoo (Integer. 1)) (.setBar (Integer. 2)) (.setBaz (Integer. 3)))] (.setInput calculator inputBean) (.performCalculation calculator) (let [resultBean (.getCalculationResultBean calculator) subresultA (.getSubresultA resultBean) subresultB (.getSubresultB resultBean)] ;; Do something with the result ))
- 16. (let [{:keys [subresult-a subresult-b]} (calc {:foo 1 :bar 2 :baz 3})] ;; Do something with the result )
- 17. RANDOM LEARNINGS... Shape of an API matters (Clojure ones tend to be simple. Big surprise!) "Clojure is not for geniuses" -Adam Bard "idiot-friendly design" -Adam Bard
- 18. RANDOM LEARNINGS CONTINUED Wrapping Java to Clojure is pretty much controlling mutability and restricting state (def c (condensator/create)) ... (condensator/on c "command" (fn [{data :data}] ...) Restrict mutable java to one instance, pass it with immutable data to clojure API
- 19. RANDOM LEARNINGS CONTINUED #2 Testing asynchronous stuff is surprisingly simple with promises (it "remote notifies and locally executes listener" (let [datapromise (promise)] (condensator/on server "remote" (fn [data] (info datapromise) (deliver datapromise (:data data)))) (tcp/send-tcp-msg :port 3030, :operation :notify, :selector "remote", :data "from-remote") (let [result (deref datapromise 3000 nil)] (should= "from-remote" result)))) A daily dose of Clojure increases programmer happiness by 63%