Gregg Wonderly wrote:
My changes to reggie to provide "never preferred classes" changed
MarshalledWrapper and EntryRep to implement
public interface MarshalledDataAccess<T> {
public T getUnmarshalledData() throws IOException,
InstantiationException,
ClassNotFoundException, IllegalAccessException ;
public List<String> getClassNames();
}
There is still some other work that I need to finalize in these
changes to get service objects to always have this information (there
are complex threads of execution and MarshalledObject use).
I made EntryRep work, and that was the big thing that I needed, so I
stopped at that point.
Creating an interface, such as the above, and putting it into play
would be helpful I think.
I also still believe that we really should change lookup to use
unmarshalled data objects (these changes are visible at
http://reef.dev.java.net) so that we can then plug in unmarshalling
contexts and metadata transport pieces to make services have enough
plug-ability that we can provide for registration and discovery of
other types of "enviroments" than just what DiscoveryV1 and V2 provide.
Gregg Wonderly
You know what, your right. Reggie is implementation specific. We need
to change that.
We need a place on svn for River 3.0 where we can make these changes and
experiment, perhaps using a minimal subset of the current codebase for
clarity while we experiment.
What components we should initially include?
The AR2 codebase is ready for release apart from some minor changes to
testing that I haven't quite gotten around to yet, no good holding up
productivity of fertile minds in the mean time... Its safe to branch.
Cheers,
Peter.
Calum Shaw-Mackay wrote:
Interesting.
Perhaps Marshalled object instances should also be decorated.
Yeah you'd need somewhere to start, and as I mentioned below about
transparency, you'd possibly need a
DEFAULT or CURRENT version, because if you're bringing in an object
foreign to the VM, and you're using
static analysis, you'd need to have the bytecodes available to
actually compare it against, having an initial
version identifier would give it a head start in terms of performance,
and you don't want to brute-force
hammer the network bringing in multiple dl jars, for a class that has
not been seen in any version in this JVM session
I think the more 'hints' you could provide to the classloader, through
either compatible version ranges or soft links
the better.
Whichever way you want to tackle this, you'll need it to be as
transparent a mechanism as possible so that service/bundles/clients
that don;t specify versions work as they always have,
Thanks Calum, good point, when version metadata doesn't exist, the
results
from Static Analysis alone could be utilised to find API compatible
import
packages. I guess classes lacking version metadata could be treated as
version 0. If someone later decides to add version metadata,
perhaps after
correcting a bug, the higher versioned package would be preferred,
provided
it remains API compatible and shares the same fully qualified
package name.
Yeah I'd say a DEFAULT (i.e. 0, although that itself may go through
changes in time) and perhaps symlink-type versioning including a
CURRENT.
In a way, what you don't want is to break compatibility unnecessarily.
Calum
