Wicket: error while processing form; how to skip to onError()?

Question

I have an AjaxFallbackButton on my page with its onSubmit and onError methods overridden. What is the best practice for dealing with exceptions/errors in the onSubmit method? Should I just stop processing it, register the error and call onError like this:

@Override
protected void onSubmit(AjaxRequestTarget target, Form<?> form) {
   ... // error 
      form.error("An exception was thrown")
      onError();
      return;
}

or is there a better way?