@Override
public void onReceive(Object message) {
if ((message instanceof TransformationJob) && backends.isEmpty()) {
TransformationJob job = (TransformationJob) message;
getSender().tell(
new JobFailed("Service unavailable, try again later", job),
getSender());
} else if (message instanceof TransformationJob) {
TransformationJob job = (TransformationJob) message;
jobCounter++;