Lazy loding - how to achieve optional lazy loading

pstruhos · **Joined:** Fri Nov 21, 2003 10:23 am **Posts:** 81

It is possible to have lazy loading optional at runtime? I would like to have method on state less session bean (SLSB), where one parameter is: boolean lazyLoding

If I set lazyLoding=false, I would like to get all object graph from method of SLSB, when I set lazyLoading=true, I would like to retrieve only "first level of data", only object with its properties, not related classes, collections...

EXAMPLE of method I would like to implement:

In POJOs I have hibernate tag:

Code:

* @hibernate.class table="XXX_TBL" proxy="com.domainmodel.Xxx"

Code:

    public List findPOJOS(boolean lazyLoading, String sQuery) throws ExceptionDAO {
        List results = null;
        Session session = getSession();
        try {
            results = (List) session.find(sQuery);
            if (!lazyLoading) {
                // here I don't know how to write generic code
                // begin - this code is not ok
                for (int i = 0; i < results.size(); i++) {
                    Object o = (Object) results.get(i);
                    Hibernate.initialize(o);
                    // here should come recursion to initialize
                    // all objects in graph
                }
                // end - this code is not ok
            }
        } catch (HibernateException he) {
            he.printStackTrace();
            throw new ExceptionDAO(he);
        } finally {
            closeSession(session);
        }
        return results;
    }

emmanuel · **Posted:** Fri Mar 19, 2004 7:13 am

No, set relation as lazy and use the fetch keyword

pstruhos · **Joined:** Fri Nov 21, 2003 10:23 am **Posts:** 81

Sorry, I don't understand how to do that. I think it is impossible in my case.

I have entity - POJO object that contain many-to-one and one-to-many mappings.

I would like to decide in runtime, if objects from other tables than base are loaded from db.

Please look at my submission in next topic:
topicUrl -> http://forum.hibernate.org/viewtopic.php?t=928960
submission -> Posted: Tue Mar 16, 2004 10:28 am Post subject: solution

Code:

// loading without foreign entity
try {
  results = (List) session.find("from InstrumentHistory");
} catch (HibernateException he) {
     he.printStackTrace();
} finally {
     session.close();
}

/* 
  here I would like to read fields of object 
  but there is problem, because session is closed
  and some fields are "proxied", so they are not null,
  and f.e. serializel try to read from this fields,
  runtime error occures: HibernateException: Could not initialize proxy - the owning Session was closed

  I would like to have this fiels null (in case of lazyLoding=true).
  How can I achieve it.
*/