How to fetch lazy properties of a lazy property

zhirenshao · **Posted:** Tue Mar 21, 2006 1:22 am

The title maybe a bit miss leading but not sure how to describe my problem, especially English's not my first language.

I had three classes, FirmUser Firm and FormType

A FirmUser has a list of Firms and each Firm has a list of FormTypes

Code:

public class FirmUser{
    private List<Firm> firms;
    
    // getter and setter
}

public class Firm{
    private List<FormType> formTypes;
    
    // getter and setter
}

public class FormType{
}

They have all been mapped in Hibernate, and fetching mode are all LAZY.

Here's how I retrieve a list of FirmUsers.

Code:

List results = session.createCriteria(FirmUser.class)
    .setFetchMode("firms", FetchMode.JOIN).list();

Now I'v got a list of FirmUser, the 'firms' property of each FirmUser has been initialised, but Hibernate did not fetch 'formTypes' for each firm, because the fetching mode is 'LAZY'

How do I get Hibernate to fetch 'formTypes' for each firm when I try retrieve a list of FirmUser?

Of course I can achieve this by setting the fetch mode to eager, it's not appropriate in my application

BlueStreak · **Posted:** Tue Mar 21, 2006 3:33 am

I have not tried the same but I can suggest you to use the static method provided by class Hibernate to achieve what you are looking for.

The method is ==> initialize(classInstance)

This method is used to poplulate all the lazy intialized properties of any class objects (may be in a list) with data fetched from the database. After intializing the object you can close the session and have access to all the information inside the fetched mapped class object.

In your case you can use
Hibernate.initialize(firmUser.getFirm());

I hope that solves the issue, if yer, please mark as solved...

zhirenshao · **Posted:** Tue Mar 21, 2006 6:30 pm

Sorry BlueStreak, it didn't work.

I think there must be some way to achieve that either in Criteria query or in HQL

BlueStreak · **Posted:** Wed Mar 22, 2006 2:55 am

Instead of using

List results = session.createCriteria(FirmUser.class)
.setFetchMode("firms", FetchMode.JOIN).list();

if you try

Criteria crit = session.createCriteria(FirmUser.class);
crit = crit.setFetchMode("firms", FetchMode.SELECT);
List results = crit.setFetchMode("firms.formTypes", FetchMode.SELECT).list();

it may help solve the issue as the hibernate API documents that
this option will instruct criteria to fetch eagerly, using a separate select.

zhirenshao · **Posted:** Wed Mar 22, 2006 3:00 am

hi BlueStreak, unfortunately, I tried 'select' fetch mode, still not working.