public Tweet(long id, String username, String text, 
                String date, String latitude, String longitude) {
        this(id, username, text, date, (Double) null, (Double) null);
        
        if (!latitude.isEmpty()) {
            this.latitude = Double.valueOf(latitude);
        }
        if (!longitude.isEmpty()) {
            this.longitude = Double.valueOf(longitude);
        }
    }