Question

I´ve got a controller which gets an JsonObject from a POST method, parses it to a Model object and saves it.

The main problem is that I have to use the database object, apply the changes over it with the new object values and then save the old one. This wouldn’t be a problem if they where 2 properties but User is a big object and I want to make some clean code there.

This is the code:

public static void userUpdate(String apikey, JsonObject body) {
    Long idUser = decode(apikey);
    User oldUser= User.findById(idUser);

    Map<String, User> userMap = new HashMap<String, User>();
    Type arrayListType = new TypeToken<Map<String, User>>(){}.getType();
    userMap = gson().fromJson(body, arrayListType);
    User user = userMap.get("user");

    oldUser.cif = user.cif;
    oldUser.date_last_mod = user.date_last_mod;
    oldUser.save();
}

Is there a way to make a merge(oldUser, user) and make oldUser.save()? Or any other ideas?

Thanks all for the help! 🙂

Answer 1

I solved it like this.

public static void userUpdate(String apikey, JsonObject body) {
    Long idUser = decode(apikey);
    User oldUser= User.findById(idUser);

    Map<String, User> userMap = new HashMap<String, User>();
    Type arrayListType = new TypeToken<Map<String, User>>(){}.getType();
    userMap = gson().fromJson(body, arrayListType);
    User user = userMap.get("user");

oldUser.em().merge(user);

oldUser.save();
}

You can get the EntityManager to make use of the merge option, I´ve to make some test but the first conclusion I make is that the object you are calling the merge for is the one who´s the slave and the one you pass as parameter is the master object which will update oldUser with the new values.

Thanks anyway 🙂