code: public Listeners<Job<T>> getOrCreateListeners()
     {
        Node node = childNode.getOrCreate("listeners");
        Listeners<Job<T>> listeners = new ListenersImpl<Job<T>>(this, "listeners", childNode, node);
        return listeners;
     }
docs: If not already created, a new <code>listeners</code> element with the given value will be created.
  Otherwise, the existing <code>listeners</code> element will be returned.
  @return  a new or existing instance of <code>Listeners<Job<T>></code>