Scheduled Thread Executor

CHANGELOG.org

@@ -1,9 +1,11 @@
+
 * Changes 
 ** 0.4.6-SNAPSHOT
 - Benjamin: ability to wrap component for both persistence-fn and logbook-fn independently.
 - Mariadb: database connection component
 - Next.jdbc: database connection component
 - Defensive measure in durable queue component
+- Scheduled Executor Service: added one-off method for non-repeating tasks
 ** 0.4.5
 - LDAP component (UnboundID LDAP SDK for Java)
 - New Redis queue component

src/system/components/scheduled_executor_service.clj

@@ -10,7 +10,8 @@
       (doseq [x xs]
         (case (:method x)
           :fixed-delay (.scheduleWithFixedDelay ^ScheduledThreadPoolExecutor s ((:f x) component) (:initial-delay x) (:period x) (:unit x))
-          :fixed-rate (.scheduleAtFixedRate ^ScheduledThreadPoolExecutor s ((:f x) component) (:initial-delay x) (:period x) (:unit x))))
+          :fixed-rate (.scheduleAtFixedRate ^ScheduledThreadPoolExecutor s ((:f x) component) (:initial-delay x) (:period x) (:unit x))
+          :one-off (.schedule ^ScheduledThreadPoolExecutor s ((:f x) component) (:initial-delay x) (:unit x))))
       (assoc component :scheduler s)))
   (stop [component]
     (when-let [scheduler (:scheduler component)]

test/system/components/scheduled_executor_service_test.clj

@@ -5,22 +5,24 @@
    (system.monitoring scheduled-executor-service
                       [core :refer [started? stopped?]])
    [clojure.test :refer [deftest is]])
-  (:import [java.util.concurrent TimeUnit]))
+  (:import [java.util.concurrent TimeUnit ScheduledThreadPoolExecutor]))
+
+(def workers [{:f (fn [component] #(println (str "fixed-rate " (:n-threads component)))) :initial-delay 0 :period 1 :unit TimeUnit/MINUTES :method :fixed-rate}
+              {:f (fn [component] #(println (str "fixed-delay " (:n-threads component)))) :initial-delay 0 :period 1 :unit TimeUnit/MINUTES :method :fixed-delay}
+              {:f (fn [component] #(println (str "one-off " (:n-threads component)))) :initial-delay 0 :unit TimeUnit/MINUTES :method :one-off}])
 
-(def workers [{:f (fn [component] #(println "Hello, World. " (:n-threads component))) :initial-delay 0 :period 1 :unit TimeUnit/MINUTES :method :fixed-rate}
-              {:f (fn [component] #(println "Hello, Worlds. " (:n-threads component))) :initial-delay 0 :period 1 :unit TimeUnit/MINUTES :method :fixed-delay}])
 (def scheduler (new-scheduler :xs workers))
 (def scheduler-with-n-threads (new-scheduler :xs workers :n-threads (+ 2 (.availableProcessors (Runtime/getRuntime)))))
 
 (deftest scheduled-executor-service-test
   (alter-var-root #'scheduler component/start)
-  (is (= java.util.concurrent.ScheduledThreadPoolExecutor (type (:scheduler scheduler))) "the scheduler is running")
+  (is (= ScheduledThreadPoolExecutor (type (:scheduler scheduler))) "the scheduler is running")
   (alter-var-root #'scheduler component/stop)
   (is (.isShutdown (:scheduler scheduler)) "the scheduler is stopped"))
 
 (deftest scheduled-executor-service-with-threads-test
   (alter-var-root #'scheduler-with-n-threads component/start)
-  (is (= java.util.concurrent.ScheduledThreadPoolExecutor (type (:scheduler scheduler-with-n-threads))) "the scheduler is running")
+  (is (= ScheduledThreadPoolExecutor (type (:scheduler scheduler-with-n-threads))) "the scheduler is running")
   (alter-var-root #'scheduler-with-n-threads component/stop)
   (is (.isShutdown (:scheduler scheduler-with-n-threads)) "the scheduler is stopped"))