Pat Monardo wrote:
> I don't think Avalon is a competitor to Turbine. Here's why. Avalon's
> mission is stated as encompassing all of software engineering whereas
> Tomcat/Turbine is focused on Servlets/Web-Apps. One of Avalon's main
> technologies is Phoenix, which it describes as a Services Kernel. It can
> be compared/contrasted with Tomcat. Tomcat is also a Services Kernel,
> but it is a Web Services Kernel. Phoenix's kernel is not limited to Web
> Services.
Avalon grew out of the vision for a server framework from JServ.
Tomcat 4 grew out of the need to have a new Jserv.
Basically they are two implementations of the same vision, but go round
telling people, they could get upset ;-)
Avalon is a framework.
Tomcat is an implementation.
> Consider the fundamental architecture consisting of two
> pieces: a Service Layer(Kernel)/Block(User). Just like Unix has two
> modes: Kernel / User. In Tomcat, the Kernel is a Web Service Layer and
> the User is a Web App (ServletContext). In Phoenix, the Kernel is a
> general Service Layer and the User is generically called a Block, of
> which there can be many types. For example, HTTPServlet Block,
> SOAPServlet Block, SMTPMailet Block, Bean Block.
This is not Avalon's architecture, it's specifically Phoenix's.
In Avalon we just have the Container-Component interaction via lifecycle.
> Avalon's services/user architecture, similar to HP's e-speak, is
> envisioned as a hierarchy of [service kernel / user block] layers. What
> it seeks to provide is a set of patterns (Framework) and reusable
> components (Excalibur) that can be shared across service/user layers and
> across blocks (user types?). So how does Turbine fit into this? I think
> simply by taking the Web-App "Block" and introducing a Service layer
> designed to make Web-App programming convenient inside what Phoenix
> would call an HTTPServlet Block and Tomcat would call a Web-App. So
> really it is to do what it is already doing with TurbineServices
> (Fulcrum) but using the patterns/toolkits of Avalon's Framework and
> Excalibur.
Yes, this is correct.
Turbine remains the same, only gaining from the hard work the Avalon
committers have done on refining the interfaces.
> Since it will run in Tomcat, it cannot really be an Avalon
> block since those are based on Phoenix. So right now all of the
> frameworks out there now are what I would call basic Kernel frameworks.
> HTTP-Servlets/SOAP-Services/EJB all are Kernels with its corresponding
> User "Block". None take things to the next level and decompose the User
> block into further refinements of Services. Turbine/Fulcrum does this
> and that is very important. So really it is not much different than what
> Turbine has been doing. A radical change would occur if Turbine wants to
> promote a good Servlet block in Phoenix (they're using Jo I believe
> which appears stagnant??) and work directly in Avalon, which it doesn't
> appear you have any intention of doing.
We're playing with a Catalina Block, we'll see where this brings us.
> But I think I agree with you
> that T3 should be firmed up because I got into this because of Scarab
> and as a potential Scarab user, I am frightened by all of the Turbine
> changes.
Avalon can only help in this regard, since the Framework is very stable
and can help in stabilizing the interfaces, rather than the opposite.
--
Nicola Ken Barozzi [EMAIL PROTECTED]
- verba volant, scripta manent -
(discussions get forgotten, just code remains)
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