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From Stephen McConnell <mcconn...@apache.org>
Subject [merlin] news flash !!
Date Tue, 08 Jul 2003 22:30:13 GMT

I've been real busy refactoring a bunch of stuff in Merlin before we 
release. Basically I've re-cut the content that was in the 
meta-info/model and meta/model packages into a new sub-project called 
"composition". Its a *much* cleaning implementation that fits in-between 
the meta-info layer and the assembly layer.

I.e. - the current Merlin runtime:

| merlin |
| assembly |
| meta |

The updated content I'm working is a follows:

| merlin (smaller) |
| activation (cleaner) |
| composition (smarter) |
| meta (tighter) |

The new composition package will deliver some really significant 
improvements in model management. By model management I mean the 
management of the combination of meta-info with mata-data within an 
execution context (i.e. classloader). This is driven by things I want to 
do on the JMX management side, but it is also taking care of a bunch of 
issues that I really wanted to close before a release (getting the 
container/component classloader separation in place, simplifying the 
appliance interface and implementation, fixing some semantic differences 
between appliance and block, simplifying the meta-data model and related 

The current Merlin runtime is partially migrated to the composition 
package. The existing composition test case block.xml is worth looking 
at. The composition package APIs are also worth a glance - its not 
totally complete - but 90% there. I'll probably commit the activation 
api within a matter of days so that everyone can see what and where I'm 
up-to (it's basically the re-cutting of the current assembly package to 
leverage the new composition model).

New features already in place include:

1. Classloaders supplied to a container a totally clean
(i.e. you need to include you own framework classes).
This will break all current appliance extensions (but
this is also a good thing - because it is forcing us
to look at how we declare the inclusion
(authorization?) of an extension within the system
classloader. I have some thoughts about this but that’s
the subject for another thread.

2. The repository model is enhanced, improved scanning
semantics translating to faster loading, extension
directories can now include repository group definitions,

All in all, I figure the above changes will be complete in a couple of 
weeks. After that the only question concerning a release date would be 
the status of a comon meta-info api. Personlly I would love to get in a 
common model before releasing - so if we are expidient about the 
meta-info seperation, chances are we can get all of this done before the 
end of the month!

Cheers, Steve.


Stephen J. McConnell

Sent via James running under Merlin as an NT service (with partial integration of the composition
package) :-)

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