How to tell Hibernate criteria to skip relations in deep level?

Question

I have hibernate entity GeUser this entity have ManyToMany relation to Pick entity, this entity has OneToOne relations to ALgo entity and this entity has ManyToMany relation with DbMatch entity. My goal is get GeUser entity but without picks.algo.matches . I want use GeUser object on my web app, but for me data about algo matches is not required, so I want to skip it before is loaded from database.

GeUser entity:

...
@Entity
public class GeUser {
   ....
   @ManyToMany
   private List<Pick> picks = new ArrayList<Pick>(0);
   ...

Pick entity:

@Entity
public class Pick {
   ...
   @OneToOne
   private Algo algo;
   ...

Algo entity:

...
@Entity
public class Algo{
    ...
    // I want to skip this when GeUser entity is loading from db. Should be e.g. matches == null
    @ManyToMany
    protected List<DbMatch> matches = new ArrayList<DbMatch>(); 
    ...

GeUser dao method:

public GeUser getUser(int user_id) {

    Criteria criteria = session.createCriteria(GeUser.class);
    criteria.add(Restrictions.eq("user_id",user_id));

    List<GeUser> users = criteria.list();

    if (users.size() > 0) {
        return users.get(0);
    } else {
        return null;
    }

}

Answer 1

This is a simple situation which can be solved with the help of Lazy loading. You can specify FetchType.LAZY matches inside Algo. matches will be loaded only when you access it within an active session.

...
@Entity
public class Algo{
    ...
    // I want to skip this when GeUser entity is loading from db. Should be e.g. matches == null
    @ManyToMany(fetch = FetchType.LAZY )
    protected List<DbMatch> matches = new ArrayList<DbMatch>(); 
    ...

For more in details about Lazy loading, please follow these tutorials:

• Stackoverflow thread - Lazy loading
• Lazy loading in hibernate
• Lazy and Eager loading

Hope it helps, feel free to comment if you need further help!