Separate out route rotation in a different method

Author: mpgxvii

kafka-connect-oura-source/src/main/java/org/radarbase/connect/rest/oura/OuraSourceTask.java

@@ -118,17 +118,19 @@ public Stream<RestRequest> requests() {
     if (this.routes == null || this.routes.isEmpty()) {
       return Stream.empty();
     }
+  
+    // Rotate routes so that all routes are requested in a round-robin manner
+    List<Route> rotatedRoutes = getRotatedRoutes();
+    return rotatedRoutes.stream()
+        .flatMap((Route r) -> StreamsKt.asStream(ouraRequestGenerator.requests(r, 100)));
+  }
 
-    // Rotate routes
+  private List<Route> getRotatedRoutes() {
     int routeStart = routeStartIndex % this.routes.size();
-    List<Route> rotatedRoutes = new ArrayList<>(this.routes.size());
-    rotatedRoutes.addAll(this.routes.subList(routeStart, this.routes.size()));
-    rotatedRoutes.addAll(this.routes.subList(0, routeStart));
+    List<Route> rotatedRoutes = new ArrayList<>(this.routes);
+    Collections.rotate(rotatedRoutes, routeStart);
     routeStartIndex = (routeStartIndex + 1) % this.routes.size();
-
-    // Generate requests per rotated route across all users (user iteration handled by generator)
-    return rotatedRoutes.stream()
-        .flatMap((Route r) -> StreamsKt.asStream(ouraRequestGenerator.requests(r, 100)));
+    return rotatedRoutes;
   }
 
   public Stream<SourceRecord> handleRequest(RestRequest req) throws IOException {