Thanks. Do you mean that the interface should be an extent-class inside the
implementation class-descriptor? It seems that it should be the other way
around e.g. the implementation class would be an extent-class inside the
interface class-descriptor?

> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Sent: Monday, November 17, 2003 2:22 AM
> To: OJB Users List
> Subject: Re: dynamic proxy HOWTO+
>
>
> Hi Ken,
>
> Ken Brewer wrote:
> > I just started using OJB and so far so good. I'm confused about
> the dynamic
> > proxies. Previous to OJB, my object model used inheritance but no
> > interfaces. Because I want lazy loading, I created an interface
> for nearly
> > every class. I simply named these interfaces 'I + classname'
> e.g. Account
> > now has an interface IAccount. I noticed that I had to change
> my cast from
> > the class to the interface when retrieving collection elements.
> >
> > 1. My application is substantially complete and has many
> references to the
> > class names e.g. Account. it seems I should have used the scheme
> > Account(interface) & AccountImpl(class) in order to avoid breaking my
> > application code references to Account, RIGHT?
>
> The OJB proxy mechanism provides a wrapper implementation for the
> concrete AccountImpl. This wrapper implementation (which does the lazy
> load) implements the interface Account.
> So in you business object you always have to use the interface Account
> to work safely with proxies.
> Of course it makes sense to have convenient naming convention to
> differentiate between interfaces and proxies. But OJB does not force you
> to any special names.
>
> > 2. When casting objects from a collection, should I cast to the
> class name
> > or proxy interface name?
>
> When using proxies always use the interface name. see explanation above.
>
> > 3. Must I include the full hierarchy, including interfaces, in my
> > repository.xml even though the interfaces are for dynamic proxies only?
>
> You must include at least one extent definition for the interface to
> allow OJB to perform queries against that interface type.
> But you do not have to declare the complete hierarchy.
>
> > 4. In the repository.xml, it seems that all superclass elements must be
> > duplicated in each subclass? Is that correct?
>
> That depends on the mapping strategy. See
> http://db.apache.org/ojb/tutorial3.html#mapping%20inheritance%20hi
erarchies
for details.


cu,
Thomas
>
> Thanks,
>
> -ken
>
>
>
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