Petals ESB Container

You want a Map of Map?
->
Set<Map<String, Map<String, String>> retrieveTopology()

The first Map contains as key the nature of topology element (Domain, SubDomain or Container).
Furthermore it can be extensible to others natures...

It's better, but hy the method will not return a bean Topology?. As the beans of topology are available through a Maven artifact, it should be easy to use on the JMX client side.

Moreover to be compliant with previous client, the existing operation should be deprecated and a new one should be introduced.

Deprecated until when?
From my point of view, i do not put any method deprecated if they are not plained to be removed at a time, i simply remove them.
Moreover which old admin client need to be compatible with new versions of Petals?
Is there any plan about that? from my point of view, there is not need of that for the moment

The point is to create a Admin API with the proper 'beans' as you called then, i call it 'classes' (bean is for J2EE environments no?)

For the moment, we just use a a simple Map/List forms for data structure with JMX clients, to avoid to handle client classloading issues. Once a proper admin API defined, we can work with that.

Deprecated until the new major version of Petals ESB (v4.0), otherwise we need to manage different version of the WebConsole that is an admin client for Petals 3.0.x, 3.1.x, ...

petals-jmx is the amin API which you talk, isn't it ?

For my point of view:
All Web Console do not work with all 3.x versions.
-old Web Console do not work necessary with new Petals versions. (Minor versions)
-New Web Console should work with all 3.x Petals, and MUST use latest feature of the latest Petals ESB.

Upgrading a Web Console is very easy and can be a a mandatory to upgrade a Petals ESB (minor version)
So we are just focusing on that new Web Console works on all Petals Minor versions (3.0, 3.1, 3.2...). Thus we do not focus on old Web Console with new Petals ESB compatibility -> less tests.
These rules permits to handle easier the evolutions, as deprecated method are never handle properly in the current way of developing (trust me i'm the main commiter on Petals ESB), as we do not plan any life duration for Petals products.

The API i speak should be a petals-admin-api library that hold all the object necessary to manipulate for an admin client.
The admin client would be at first time JMX, but can be after Web Service....
This library would need to be embedded in any admin client classloader.

This library do not exist at current time. There is only a petals-jmx-api which is not technology agnostic.