HOW-TO: programatic lazy loading

joostschouten · **Posted:** Tue Mar 27, 2007 12:03 am

Hi,

After quite a search I have not found a way to map a collection generated by a query using the GROUP BY clause and populating one of the values with a sum().

The query is fairly straight forward and works fine in SQL and HQL. For this reason I want to load the collection programatically. I can do this with the

Code:

public boolean onLoad(Object entity,Serializable id,Object[] state,String[] propertyNames,Type[] types){}

from the EmptyInterceptor

But I prefer lazy fetching becuse of performance reasons. How do I go about setting this up. Ho can I tell hibernate to populate my collection when it is called by it's getter getSummedCredit() in my User bean?

My bean getter and setter:

Code:

 public Set getSummedCredit(){
        return this.summedCredit;
    }
    
    public void setSummedCredit(Set summedCredit) {
        this.summedCredit = summedCredit;
    }

My SQL:

Code:

SELECT sum(sc.amount) as amount sc.currency FROM transactions sc WHERE sc.receiver=:id AND sc.reservation=0 GROUP BY sc.receiver, sc.currency

Thank you very much for your help.
Best regards,