SOAP, Servlets, Lifecycle - Architecture Question

[Julian Gosnell <ju...@yahoo.com>]

I have two process types - a Master and a number of
Slaves.

A Slave's lifecycle looks like this.

It is born, registers with it's Master (via SOAP),
sit's around ready to respond to it's Master's bidding
for a while, (bidding will arrive as a SOAP RMI), then
deregisters from Master (via SOAP) and shuts down.

A Slave has a Servlet component, which is responsible
for generating HTML reports on the Slave's status.

A Slave needs a lifecycle - so it knows when to
register, listen and deregister.

A Slave needs a SOAP client component, to make calls
to it's Master.

A Slave needs a SOAP service component, to receive
calls from it's Master.


My question is:

How should the objects that implement these components
intersect/communicate with each other?

My initial thought was to take advantage of the
lifecycle offered by the Servlet. The Servlet
lifecycle would be the Slave's lifecycle. The Servlet
would contain SOAP client code etc... I figured that I
should also publish a subset of the Servlet's API as
the SOAP service expected by the Master. Then I ran
into trouble. It looks to me as if the JavaProvider
assumes total control over it's 'deployee's lifecycle.
So I would need a custom ServletProvider, which looks
up the Servlet and delegates calls to it. Then again,
I'm not sure that JSDK allows me to get hold of a
Servlet object at all, and the whole thing begins to
sound hacky as the neat distinction between HTML
presentation, Service provision and Slave lifecycle
and logic is lost.

So then I considered keeping all these components
separate, but making a single common data model
available to all of them, but this began to look way
too complicated, especially as the Slave lifecycle,
now separate from the Servlet's governs an object
which is not a Servlet or SOAP service - where would
it live ? not within the WebContainer....


I can't believe that this is not a common
architectural problem faced by many Web Application
developers.

In conclusion:

Who IS the application ? The Servlet, the SOAP Service
or neither? and if neither, What is the application,
and Where is it?

I guess that about wraps it up - If I have completely
misunderstood please feel free to flame away - I'm
climbing into my flameproof trousers as we speak.

Thanks for your time,



Jules




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