add a build method and export statement

src/entities/System.ts

@@ -1,11 +1,34 @@
-import { ShuttleGetterSetterRepository } from "../repositories/ShuttleGetterSetterRepository";
 import { ShuttleRepositoryLoader } from "../loaders/ShuttleRepositoryLoader";
+import { ETANotificationScheduler } from "../notifications/schedulers/ETANotificationScheduler";
+import { TimedApiBasedShuttleRepositoryLoader } from "../loaders/TimedApiBasedShuttleRepositoryLoader";
+import { UnoptimizedInMemoryShuttleRepository } from "../repositories/UnoptimizedInMemoryShuttleRepository";
+import { RedisNotificationRepository } from "../repositories/RedisNotificationRepository";
 
-class System {
+export class System {
   constructor(
     public systemId: string,
-    public shuttleRepository: ShuttleGetterSetterRepository,
     public shuttleDataLoader: ShuttleRepositoryLoader,
+    public notificationScheduler: ETANotificationScheduler,
   ) {
   }
+
+  /**
+   * Construct an instance of the class where all composited
+   * classes are correctly linked.
+   * @param systemId
+   */
+  static build(systemId: string) {
+    const shuttleRepository = new UnoptimizedInMemoryShuttleRepository();
+    const shuttleDataLoader = new TimedApiBasedShuttleRepositoryLoader(systemId, shuttleRepository);
+
+    const notificationRepository = new RedisNotificationRepository();
+    const notificationScheduler = new ETANotificationScheduler(shuttleRepository, notificationRepository);
+
+    const system = new System(
+      systemId,
+      shuttleDataLoader,
+      notificationScheduler,
+    );
+    return system;
+  }
 }