Related #32: asynchronously load implementation

saves 200ms on my machine

before:
user=> (time ((requiring-resolve 'java-time/instant)))
"Elapsed time: 1363.621694 msecs"

after:
user=> (time ((requiring-resolve 'java-time/instant)))
"Elapsed time: 1113.720916 msecs"

Author: frenchy64

CHANGELOG.md

@@ -8,8 +8,10 @@
 * #81(terop): Remove clj-tuple - no advantages over Clojure vector anymore
 * Remove `java-time.util/get-static-fields-of-type`
   * set Java property `java-time.util.get-static-fields-of-type=true` to revert
-* #32: Lazily load implementation
+* #32: Asynchronously load implementation
   * new function `java-time/load-java-time` to force loading
+  * by default, implementation is loaded asynchronously, use system property `java-time.no-async-load=true`
+    to disable
 
 ## 0.3.3
 

src/java_time.cljc

@@ -2,7 +2,7 @@
 (ns java-time (:refer-clojure :exclude (zero? range iterate max min contains? format abs)) (:require [java-time.util :as jt.u] java-time.clock java-time.util))
 (let [lock (Object.) do-load (delay (locking lock (require 'java-time.adjuster 'java-time.amount 'java-time.chrono 'java-time.clock 'java-time.convert 'java-time.core 'java-time.format 'java-time.interval 'java-time.joda 'java-time.local 'java-time.pre-java8 'java-time.properties 'java-time.seqs 'java-time.single-field 'java-time.sugar 'java-time.temporal 'java-time.zone #?@(:bb [] :default ['java-time.mock]))))]
   (defn load-java-time "Load java-time implementation" [] @do-load))
-(when *compile-files* (load-java-time))
+(if *compile-files* (load-java-time) (when-not (= "true" (System/getProperty "java-time.no-async-load")) (.start (Thread. (fn [] (load-java-time))))))
 (defmacro with-clock {:doc "Executes the given `forms` in the scope of the provided `clock`.\n\n  All the temporal entities that get created without parameters will inherit\n  their values from the clock:\n\n    (with-clock (system-clock \"Europe/London\")\n      (zone-id))\n    => #<java.time.ZoneRegion Europe/London>"} ([c & forms] (list* (quote java-time.clock/with-clock) c forms)))
 (defmacro when-joda-time-loaded {:doc "Execute the `body` when Joda-Time classes are found on the classpath.\n\n  Take care - when AOT-compiling code using this macro, the Joda-Time classes\n  must be on the classpath at compile time!"} ([& body] (list* (quote java-time.util/when-joda-time-loaded) body)))
 (let [+impl+ (delay (load-java-time) (deref (resolve (quote java-time.clock/with-clock-fn))))] (defn with-clock-fn {:doc "Executes the given function in the scope of the provided clock. All the\n  temporal entities that get created without parameters will inherit their\n  values from the clock."} ([c f] ((deref +impl+) c f))))

test/java_time/dev/gen.clj

@@ -173,7 +173,10 @@
                     ~@(sort require-macros)))
        (format "(let [lock (Object.) do-load (delay (locking lock (require %s #?@(:bb [] :default ['java-time.mock]))))]\n  (defn load-java-time \"Load java-time implementation\" [] @do-load))"
                (str/join " " (map #(str "'" %) (sort (disj require-fns 'java-time.mock)))))
-       '(when *compile-files* (load-java-time))]
+       '(if *compile-files*
+          (load-java-time)
+          (when-not (= "true" (System/getProperty "java-time.no-async-load"))
+            (.start (Thread. (fn [] (load-java-time))))))]
       (apply import-vars (:macros impl-info))
       (apply import-vars (:fns impl-info))
       (map #(list 'jt.u/when-threeten-extra %) (apply import-vars (:threeten-extra-fns impl-info))))))