Merge pull request #1231 from e210/main

Improve Singleton instantiation in SchedulerRepository
quartz-scheduler · Oct 30, 2024 · 19e622c · 19e622c
2 parents d12b678 + a5e80ba
commit 19e622c
Showing 1 changed file with 9 additions and 12 deletions.
diff --git a/quartz/src/main/java/org/quartz/impl/SchedulerRepository.java b/quartz/src/main/java/org/quartz/impl/SchedulerRepository.java
@@ -45,39 +45,36 @@ public class SchedulerRepository {
 
     private final HashMap<String, Scheduler> schedulers;
 
-    private static SchedulerRepository inst;
-
     /*
      * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-     * 
+     *
      * Constructors.
-     * 
+     *
      * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      */
 
     private SchedulerRepository() {
         schedulers = new HashMap<>();
     }
 
+    private static class Holder {
+        private static final SchedulerRepository INSTANCE = new SchedulerRepository();
+    }
     /*
      * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-     * 
+     *
      * Interface.
-     * 
+     *
      * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      */
 
     public static synchronized SchedulerRepository getInstance() {
-        if (inst == null) {
-            inst = new SchedulerRepository();
-        }
-
-        return inst;
+        return Holder.INSTANCE;
     }
 
     public synchronized void bind(Scheduler sched) throws SchedulerException {
 
-        if ((Scheduler) schedulers.get(sched.getSchedulerName()) != null) {
+        if (schedulers.get(sched.getSchedulerName()) != null) {
             throw new SchedulerException("Scheduler with name '"
                     + sched.getSchedulerName() + "' already exists.");
         }