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Make random-fodder-seq thread safe #31

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Make random-fodder-seq thread safe #31

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9 changes: 9 additions & 0 deletions api/spec/hyperion/key_spec.clj
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,15 @@
(should= true (seq? (random-fodder-seq)))
(should= 10 (count (set (map (fn [_] (take 5 (random-fodder-seq))) (range 10))))))

(it "random-fodder-seq is threadsafe"
(should= 250
(reduce +
(map
(fn[_] (count (set (pmap
(fn [_] (take 10 (random-fodder-seq)))
(range 50)))))
(range 5)))))

; (it "generate key times"
; (prn (take 100 (iterate (fn [_] (generate-id)) nil)))
; (prn (take 100 (iterate (fn [_] (generate-id2)) nil)))
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8 changes: 7 additions & 1 deletion api/src/hyperion/key.clj
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Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,13 @@
(def fodder-count (count key-fodder))

(defn random-fodder-seq
([] (random-fodder-seq (java.util.Random. (System/nanoTime))))
"The default generator for `random-fodder-seq` is threadsafe for JDK 1.6b73
or greater (http://bugs.java.com/view_bug.do?bug_id=6379897). Calls to this on
multiple threads (i.e. `(pmap (fn [_] (take 10 random-fodder-seq)) (range 10))`)
will have a different seed for each instance of `java.util.Random`. If on a JDK
earlier than JDK 1.6b73 there is a chance that there will be multiple instances
of `java.util.Random` with the same seed causing collisions"
([] (random-fodder-seq (java.util.Random.)))
([generator]
(cons
(aget key-fodder (.nextInt generator fodder-count))
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