JSON.getDefault().addConvertor(Resource.class, new Convertor()
    {
      public void toJSON(Object obj, Output out) 
      {
        Resource resource = (Resource) obj;
        out.add("uri", resource.getUri());
      }
      public Object fromJSON(Map object)  { return null; }
    });
    JSON.getDefault().addConvertor(EventResource.class, new Convertor()
    {
      public void toJSON(Object obj, Output out) 
      {
        EventResource resource = (EventResource) obj;
        out.add("uri", resource.getUri());
        out.add("subscriptions", resource.getSubscriptions());
      }
      public Object fromJSON(Map object)  { return null; }
    });
    JSON.getDefault().addConvertor(Subscription.class, new Convertor()
    {