[jboss-as7-dev] how to access the management model?

[Jason T. Greene]

On 3/28/11 3:38 AM, André Dietisheim wrote:
> Hi Jason
>
>>> hmm, to be honest I dont really understand why a RESTy semantic (ex.
>>> post to or delete to the uri of the cache resource) would not allow this
>>> operation. But I might miss something here since I do not have the same
>>> background.
>>
>> It's purely an issue of complexity. A more RPC approach has the
>> benefit that any subsystem can expose any runtime call it wishes to by
>> just adding a method and a mapping. In a REST approach you have to
>> come up with clever ways to map what ever you are doing to a CRUD
>> resource tree, this puts a lot of burden on subsystem developers.
>
> I obviously lack the knowledge about your requirements and the way the
> subsystems communicate with the service interface.
> I agree with you about the complexity in providing a consistent URI
> space (~mapping). But I'd argue that you have the same design decisions
> in classic RPC style, too. In the end REST style just offers you to
> model operations on URI's and HTTP methods instead of RPC method
> parameters.

You are comparing an unrestricted contract to one that is restricted to 
CRUD calls. Since programming languages are naturally procedurally 
oriented, the latter is always more work unless what you are exposing is 
naturally a simple CRUD operation.

If you still disagree, try converting the Java SE or EE APIs to CRUD.

>> Also note that we support complex transactional operations (e.g. apply
>> this change to 15 servers and if more than 4 of them fail roll it
>> back) which do not map cleaning to a simple READ/UPDATE/DELETE URL
>> model. You end up having to create virtual session specific objects
>> for every client.
>
> I'd argue that the mapping challenge is a matter of design and not the
> inability in REST to offer transactions. I usually impleted this in a
> transaction resource that was PUT the operations to (which then are
> usually a set of URI of the resource to manipulate, the method to use
> and ev. params).

Adding multiple network round trips and a bunch of state to the server 
just to comply with the design paradigm du jour just seems wrong to me.
-- 
Jason T. Greene
JBoss, a division of Red Hat