RE: [Hibernate] Using hibernate - best practices

[Hiram C. <hch...@jb...>]

First time post... I like hibernate.  I want to use it more with the Aspect
Framework that I'm build for JBoss.  Anyways, here is a way a Jboss aspect
could help simplify things:

You would use an interceptor that had an invoke method that looked something
like:

class HibernateInterceptor {
...
		public Object invoke(AspectInvocation invocation) throws Throwable {

			HibernateContext oldHC = getHibernateContext();
			HibernateContext hc = null;
			if( oldHC==null || oldHC.sessionFactory != sessionFactory ) {
				hc = new HibernateContext();
				hc.sessionFactory = sessionFactory;
				hc.session = sessionFactory.openSession();
				hc.transaction = hc.session.beginTransaction();
				setHibernateContext(hc);
			}

			try {

				Object rc = invocation.invokeNext();

				if( hc != null )
				    hc.transaction.commit();

				return rc;

			} catch ( Throwable e ) {
				if( hc != null )
				    hc.transaction.rollback();
			    throw e;
			} finally {
				if( hc != null )
				    hc.session.close();

				setHibernateContext(oldHC);
			}
		}
..
}

class RuleListAction implemetns IRuleListAction {
..
	public String doDelete() throws Exception {
		Session session= HibernateInterceptor.getSession();
		RuleList mo = (RuleList) session.load( RuleList.class, id );
		session.delete(mo);
		return SUCCESS;
	}
..
}

so that if you have DynamicProxy x with the HibernateInterceptor in the
invocation chain
then you could just do a:

IRuleListAction x = (IRuleListAction )AspectFactory(new RuleListAction());
x.doDelete()

Regards,
Hiram



> -----Original Message-----
> From: hib...@li...
> [mailto:hib...@li...]On Behalf Of Urberg,
> John
> Sent: Friday, November 15, 2002 8:30 AM
> To: 'Jozsa Kristof'
> Cc: hib...@li...
> Subject: RE: [Hibernate] Using hibernate - best practices
>
>
> >> The InvoiceRepository would be implemented like this:
> >> [code to load invoices]
>
> > And where do you close those opened sessions using this design? Also,
> where
> > did you find a place to implement transaction handling,
> including joining
> > into existing transactions if possible?
>
> That's the responsibility of the database object.  Code will usually look
> something like this:
>
>    SomeRepository someRepository = database.getRepository(...);
>    AnotherRepository anotherRepository = database.getRepository(...);
>    database.startTrans();
>    try {
>       someRepository.update(object);
>       anotherRepository.update(object);
>       database.commit();
>    } catch (Exception e) {
>       database.rollback();
>    }
>
> All the code for dealing with sessions and transactions is safely tucked
> away in the database implementation.
>
> > These piece of codes are repeating in almost ALL of the Service classes'
> > business methods, are just flooding all the logic badly :(
>
> I'm not sure how you get around the whole transaction thing
> unless you're in
> a J2EE server that does that automatically.  If you want to get rid of the
> boilerplate code, you could do something like this:
>
>   public class Database {
>     <...>
>     public void inTransactionDo(Runnable doRun) {
>       Session session = null;
>       Transaction tx = null;
>       try {
> 	  session = Hibernator.getSession();
> 	  tx = session.beginTransaction();
>         doRun.run();
> 	  tx.commit();
>       } catch (Exception e) {
> 	  logger.error (<blah/>), e);
> 	  tx.rollback();
>       } finally {
> 	   if (session != null) session.close();
>      }
>      <...>
>   }
>
> Then your business methods would look like this:
>
>   database.inTransactionDo(new Runnable() {
>     public void run() {
>      <...business logic here...>
>     }
>   }
>
> Regards,
> John Urberg
>
>
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