Re: [Springframework-developer] Question/ potential patch for org.springframework.orm.hibernate3.HibernateTemplate

[Colin Y. <col...@gm...>]

Actually, althought the javadoc doesn't explicitly mention it (and is quite
badly worded actually) load won't hit the database if your class is proxied.
This is mentioned in the reference documentation (section 10.3) and is
encapsulated in the org.hibernate.event.def.DefaultLoadEventListener.

Given these semantics are defined by Hibernate I am not really sure that
Spring should change the behaviour as it would quite unintuitive.

To our original question, I believe even if the class *is* lazy loaded, load
would still hit the database to confirm identity but that is an assumption
and I haven't traced it through to verify that behaviour.  The Javadocs do
make it clear that load should only be used for known persistent objects, if
in doubt, use get.

Col

P.S.  I think I will write a couple of tests to verify this behaviour and
will get back to you.

On 26/07/06, Colin Yates <col...@gm...> wrote:
>
> Hi Bill,
>
> Hibernate3 only makes relationships lazy by default, not the class.  This
> is sensible (in my opinion) because most of the time there is no real reason
> to load the class in seperate chunks (aka field groups).   I believe that
> they actually mention in their documentation that they only support lazy
> loading of the class in order to "tick a box" :)
>
> Also, checking out the hibernate document for the hibernate Session ( http://hibernate.org/hib_docs/v3/api/org/hibernate/Session.html#load(java.lang.Class,%20java.io.Serializable)
>
> <http://hibernate.org/hib_docs/v3/api/org/hibernate/Session.html#load%28java.lang.Class,%20java.io.Serializable%29>)
> indicates that the load methods *do* check that the object exists.  So
> hibernate will throw its HibernateException and Spring will then convert
> this into one of its own DataAccessException.
>
> HTH.
>
> On 26/07/06, Bill Six <bil...@ya...> wrote:
>
> > Hi,
>
> I have a question about the load() methods on
> hibernate3's HibernateTemplate.
>
> Spring's javadoc for load() say that an exception will
> be thrown if the object is not found.  However, from
> what I understand, Hibernate 3 changed its default
> behavior to lazy load all classes.  This means that if
> you try to load an object with an ID that does not
> exist, a Hibernate error is not thrown because you get
> a proxy to the object that does not exist.  It is only
> upon the first method call to that proxy that
> Hibernate's ObjectNotFoundException is thrown.  I
> would think that in Spring's load() methods should
> force initilization of that object so that trying to
> load an object that does not exist immediately throws
> the correct Spring exception.
>
> I have attached a patch that should do the trick.  I
> have never made a patch before, nor have I ever looked
> through the source of spring or hibernate, so please
> excuse any stupid mistakes :-)
>
> Thanks for a great product,
>
> Bill Six
>
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