Hi again,

> Anyone with an answer to this one also ? :)
> 
> 
> > > > 3. When the objects (proxies) are serialized onto the 
> client then the
> > proxy
> > > > has an internally reference to the
> > > > persistence broker that "gave birth" to them - and this 
> persistence
> > broker
> > > > is probably holding a reference to
> > > > a connection to the database - That is NOT healthy in a 2/3-tier
> > solution.
> > > > Or have I misunderstood how it works ?
> > >
> > > The proxies are marshalle *without* the server-side broker. On the
> > > client a Broker stub is used to access the server. Thus no
> > > jdbc-connection related stuff is send to the client.
> >
> > Ok - this is more healthy than my "nightmare"-description :)
> > But how does the stub communicate with the server ? Via RMI, or ?
> > Well - what I want is that the client CANNOT communicate 
> silently behind
> > the programmers back when he is "dotting"-around in the model.
> >
> > >
> > > > 4. And in C/S mode the "client" also have a 
> persistencebroker, right ?
> > >
> > > a PB stub only, that delegates all calls to the server-side PB.
> >
> > And this server-side PB is shared amongst clients ? Does it keep the
> > connection "forever" ?

No, the server-side brokers are bound to the remote client to allow safe
transactions!

> >
> > > > Then
> > > > the client suddenly can access the database without having the
> > app.server as
> > > > a middle-man ?
> > >
> > > There is a servlet based PB server implementation. thus 
> it is possible
> > > to have all jdbc-connection and transaction related stuff 
> under full
> > > control of the app server.
> >
> > Yes - and the servlet based stuff could probably be extended to be a
> session
> > bean or similar.

exactly!

> > But - still the client would have more or less direct 
> contact with the
> > "database". I would like to have a layer between the client 
> and the actual
> > persistencemechanism....maybe a dream, but I think it is a 
> necessary dream
> > :)

It's possible to prevent remote clients from accessing a broker by sending
them objects that have no proxies inside. (by setting proxy="false" on
reference- and collection descriptors)

I already checked in the support for
PersistenceBroker.retrieveReference(instance, attributeName) to allow
explicit loading of references and collections !

cheers,
Thomas


> >
> > /max
> >
> >
> >
> >
> >
> >
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