@Override
  public void setValue(MyBeanItemContainer newValue) throws ReadOnlyException {
    if (List.class.isAssignableFrom(f.getType())) {
      try {
        List list = (List) f.get(instance);
        list.clear();

        for (Object itemId : container.getItemIds()) {
          Object bean = container.getUnfilteredItem(itemId).getBean();
          list.add(bean);
        }
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
  }
 @Override
 public Class<? extends MyBeanItemContainer> getType() {
   return container.getClass();
 }