Re: [CFCDev] Best Methodology/Framework for building RIA

[Matt Liotta]

I think I can speak directly to the architecture question based on my 
experience in building architectures over the years and my more recent 
experience with a very complex Rich Internet Application. I have seen 
many try and shoehorn a three-tier architecture into something useful 
for a Rich Internet Application by simply adding a facade to their 
business-tier. However, this tends to fall down because as it turns out 
many of the assumptions made in the presentation-tier of a web 
application are very different to those of a Flash application. Of 
course, you would expect that, but it seems that the assumptions some 
how spread to the business-tier thus infecting there two distinctly 
different presentation-tiers. I have seen people put a lot of work into 
their facade to make up for this, but that is a futile effort IMHO. An 
ivory tower view would be that a tight coupling between the 
presentation-tier and the business-tier is the problem. Well that may 
be, but I have realized that while decoupling may be a worthy goal it 
often isn't practical in a three-tier approach. That isn't to say there 
isn't an answer; it is just to say that I didn't find one with a 
three-tier approach.

I have found a four-tier architecture to be most appropriate. The four 
tiers are database, service, business, and presentation. The 
database-tier and presentation-tier is no different than you would have 
in a three-tier architecture. The service-tier wraps up the 
database-tier as a service as well as any other things an application 
might need such as authentication and authorization, workflow, search, 
etc. None of these services enforce business rules for an application. 
In fact, they are designed such that they no nothing of the application 
that uses them. Further, these services are available from a variety of 
APIs depending on the needs of the application. In most of my 
applications the services are available as a local object or as a web 
service. The business-tier is a little more tricky. It needs to wrap 
the service-tier and enforce business rules for the application. 
However, since the kind of applications we are talking about are both 
HTML and Flash-based there needs to be two implementations of the 
business-tier, one in CFML/Java and one in Flash. The CF-based 
presentation-tier would use a business-tier implemented in CFML and/or 
Java, while the Flash-based presentation-tier would use a business-tier 
implemented in Flash.

Now some may think initially that having two different business-tier 
implementations is a bad thing. However, I have found that once you 
separate out the "business" services into their own distinct tier, what 
is left tends to be specific to the application and a web application 
is really different than a Rich Internet Application. Thus, the 
four-tier approach actually gives maximum reuse, while maintaining 
proper separation. As you can imagine, in the context of a web 
application the service-tier is accessed using a local object API, 
while in the context of a Rich Internet Application the service-tier is 
accessed using a web service API.

Matt Liotta
President & CEO
Montara Software, Inc.
http://www.MontaraSoftware.com
(888) 408-0900 x901
On Dec 6, 2003, at 7:35 AM, robi sen wrote:

Sean,

Can you mention any Frameworks or Methodologies that focus on more of
service oriented architecture or approach to building applications that
are focused on using web services?
Thanks,

R

"Like Flash / Flash Remoting, Flex also requires a remote-CFC interface
to interact with ColdFusion so I suspect that similar concerns apply
for integrating Mach II with Flex, i.e., the problem is that Mach II
does not expose a Web Service-style API."


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