public static Rengine getRengine() {
if (rengine == null) {
try {
System.out.println("Rengine Trying to construct rengine");
rengine = new Rengine(null, false, new Rdao());
} catch (Exception e) {
System.out.println("Rengine construct Error");
e.printStackTrace(); // neue Exception bauen nochmal fragen
// TODO: handle exception
}