Hi Guys,

I'd like to give you an update on current status of the OSGI branch, and ask your opinions on some topics...

First of all, now we have ApacheDS running in OSGI, capable of reconfiguring itself on the fly (partially for now just for test, only server itself along with interceptors and some other things.). And server startup time is not bad, which i've always been suspicious about. Here are the core features of component-hub.

Developer features:

* Hub is designed to work with any OSGI compliant Component Framework. Not all frameworks can use all features of hub because of their own nature, but now we have an aggregator layer which is able to work with every one of them.
I used IPojo components while testing the integration, but also implemented declerativeservices connector just as proof of concept, blueprint on the way.

* Component Framework, Factories and Components are isolated from ApacheDS code using abstractions, nothing OSGI specific goes into code.(of some degree of course)

Configuration Model:

* Through hub, these configuration options can be described in LDAP and passed to components, inside brackets are the compatible framework types.

      * Collections (List,Set,Array) (Only IPojo)
      * Any other component reference (Blueprint & IPojo)
      * Java Primitive types(all component framework)
      * Object injection,(This is any type like SchemaManager, InstanceLayout, DirectoryService ext... can be injected into components) (Blueprint & IPojo)

* Inside config-partition, no special hierarchy rule is necessary. We can pick any placing as we see fit, and then change it, no worries.

* Configurations are updatable meaning if we update some component with new version which has different configuration(additions/deletions) existing configurations are updated to work with new component.( Some update types are not possible, so we loose existing component descriptors, but works for most of the scenarious.

Runtime Model:

* Through a special interceptor, ADD,DELETE,MODIFY operations on config-partition are tracked and reflected to hub. Event listeners can be attached to component-hub for getting component events, registrations are class type based, so one piece of code can track what is going about components implementing Interceptor.class in component-hub.

* For components having another components and collections as property, all changes are propagated back to their parent. For IPojo only their setter methods (if declared) are called too even if runtime Object reference is not changed at all.

* Event trackers can take action in life-cycle events of components. This feature is usefull for keeping ApacheDS away from dropping into inconsistent configuration. For example, the test integration i implemented mandates component-hub having at least one intreceptor for every interception point in server.


1- JDBM serialization uses plain ObjectInputReader for deserializing, which is failing in an OSGI environment. We have find some nice way to handle that, i handled it by adding required classes to boot delegation path of OSGI, which is not viable for production. Our possible solutions are either redeclaring these classes under JDBM and AVL (I don't know if possible) or subclassing ObjectInputReader to delegate class loads to correct class-loader in an OSGI environment.

2-  JDBM partition is so static. Any tiny reconfiguration after it's been initialized throws an Exception out of nowhere. Under this runtime characteristics i left out partitions in my initial integration tests. They need some work to be done in order to be reconfigurable in runtime.(Adding/removing user attribute index at runtime would be a good start).

3 - I'm having nightmares with logging in eclipse-equinox. I just couldn't find a way to adjust logging settings. Thanks to schema-loader's massive DEBUG output, i'm left with System.out.println() here, having disabled logging. Pierre i'd use a little help here :)

After these problems are solved, you'll be able to test and stretch the system in your local copy. Until this time i'll improve it as much as i can, and under your guidances i'll try to find some fit configuration model for all server components.

Lets talk more !