Google App Engine Objectify get grandson of entity - google-app-engine

Question

I have entities like this : User->Blague->Score where an user have numerous blagues(childs) and a blague have one score.
I'm trying to get the score from a blague, but when I write this :
User userPoster = ofy().load().type(User.class).id(5066549580791808L).now();
Blague blague = ofy().load().type(Blague.class).parent(userPoster).id(4609152743636992L).now();
Score score = ofy().load().type(Score.class).parent(blague).id(5735052650479616L).now();
resp.getWriter().println(userPoster);
resp.getWriter().println(blague);
resp.getWriter().println(score);
(The ids are corrects) score is null, unlike blague and userPoster. Why is it null ?
The entities are created like that :
#ApiMethod(
name = "addBlague",
path = "addBlague",
httpMethod = ApiMethod.HttpMethod.POST)
public void addBlague(
#Named("category") EnumCategory category,
#Named("type") EnumType type,
#Named("lenght") EnumLenght lenght,
#Named("keywords") List<String> keywords,
#Named("text") String text,
#Named("userId") Long userId){
Key<User> userKey = Key.create(User.class, userId);
Blague blague = new Blague(category, type, lenght, text, userKey);
ofy().save().entity(blague).now();
Key<Blague> blagueKey = Key.create(Blague.class, blague.getId());
Score score = new Score(0, 0, blagueKey);
ofy().save().entity(score).now();
for (String word : keywords) {
KeyWord keyword = new KeyWord(word, blagueKey);
ofy().save().entity(keyword);
}
}
and of course, the classes are registered.
How can I get the score from a blague ?
Thanks
Edit :
The Socre code :
package blagueur;
import java.util.HashMap;
import com.googlecode.objectify.Key;
import com.googlecode.objectify.annotation.Cache;
import com.googlecode.objectify.annotation.Entity;
import com.googlecode.objectify.annotation.Id;
import com.googlecode.objectify.annotation.Index;
import com.googlecode.objectify.annotation.Parent;
#Entity
#Index
#Cache
public class Score {
#Id
private Long id;
private int likes;
private int dislikes;
private HashMap<String, Boolean> voters;
#Parent
private Key<Blague> blagueKey;
private Score() {}
public Score(int likes, int dislikes, Key<Blague> blague) {
this.likes = likes;
this.dislikes = dislikes;
this.blagueKey = blague;
this.voters = new HashMap<String, Boolean>();
}
public Long getId() {
return id;
}
public int getLikes() {
return likes;
}
public int getDislikes() {
return dislikes;
}
public void addVote(Long userId, boolean like){
voters.put(String.valueOf(userId), like);
if (like){
likes++;
}
else{
dislikes++;
}
}
public void removeVote(Long userId){
String id = String.valueOf(userId);
boolean like = voters.get(String.valueOf(userId));
voters.remove(String.valueOf(userId));
if (like){
likes--;
}
else{
dislikes--;
}
}
public Key<Blague> getBlagueKey() {
return blagueKey;
}
}

Answer 1

You need to be very careful to maintain the key hierarchy.
You state that your intended entity hierarchy is User -> Blague -> Score, but this code below does not do that:
Key<User> userKey = Key.create(User.class, userId);
Blague blague = new Blague(category, type, lenght, text, userKey);
ofy().save().entity(blague).now();
Key<Blague> blagueKey = Key.create(Blague.class, blague.getId());
Score score = new Score(0, 0, blagueKey);
ofy().save().entity(score).now();
When you create the blagueKey, you do not use the userKey as the parent.
While I do not encourage the code style you have written, if you wanted to do so, you need to do this:
...
Key<Blague> blagueKey = Key.create(userKey, Blague.class, blague.getId());
...
In general, you should let objectify handle this for you by using Ref<User>, Ref<Blague> as the #Parent objects, or if you must create Key objects, use Key.create(T pojo) rather than managing Keys yourself.