if a mistake occurs during cache creation, all previously created stations related to that cache get deleted now

src/main/java/hhn/labsw/bugageocaching/controller/Controller.java

@@ -151,21 +151,25 @@ public class Controller {
     for (Station station : cache.getStationen()) {
       ResponseEntity response = createStation(station);
       if (response.getStatusCodeValue() == 400) {
+        deleteStationen(cache);
         return response;
       }
     }
 
     if (cache.getDescription().length() == 0 || cache.getName().length() == 0 || Double.valueOf(cache.getRankingPoints()) == null || cache.getStationen().size() == 0) {
+      deleteStationen(cache);
       return ResponseEntity.status(400).body("cache fields can´t be empty");
     }
 
     for (Cache cache1 : cacheRepository.findAll()) {
       if (cache1.getName().equals(cache.getName())) {
+        deleteStationen(cache);
         return ResponseEntity.status(400).body("name is already taken");
       }
     }
 
     if (cache.getRankingPoints() < 0) {
+      deleteStationen(cache);
       return ResponseEntity.status(400).body("Ranking points has to be a positive number");
     }
 
@@ -218,6 +222,16 @@ public class Controller {
     return ResponseEntity.status(200).body(new Gson().toJson(station));
   }
 
+  public void deleteStationen(Cache cache) {
+    for (Station station : cache.getStationen()) {
+      try {
+        stationRepository.delete(station);
+      } catch (IllegalArgumentException e) { // station is null
+        // do nothing
+      }
+    }
+  }
+
 
   @CrossOrigin(origins = "http://localhost:8081") // only for dev purpose
   @RequestMapping("/api/checkAdmin")