Re: [service-orientated-architecture] John on Gartner, AJAX & Assorted TLAs

Thu, 17 Aug 2006 08:10:40 -0700

Hi Stefan,
 
Certainly you can use UML to create services - as has been mentioned many times in this forum you can really use any technology, including procedure oriented technologies such as COBOL or PL/I.
 
I agree EMF is simpler and it is easier with EMF to create a modeling language for services, and we are currently currently working along those lines at the Eclipse STP Project.  Microsoft has recently also released a Web service software factory, which also looks on first glance to be more service oriented.
 
But the point is more about what's better suited to service orientation, and because UML is object oriented it forces the same kind of mental translation as you'd have to do in going from procedure orientation to object orientation or service orientation.  Why not work with tools more suited to the SO concept?
 
Objects are really overkill for software design.  I believe it's time to basically turn back the clock and reject objects as the conceptual basis of modeling software.  OO creates more problems than it solves.  (Implementing services using objects, procedures, queues, etc. is ok but let's not design them that way.)  It is much better to model, design, and develop using services natively.  Most software applications are designed around implmenting functions rather than things.
 
Modeling services such as "get customer data" as the "get method on the customer object" is overly complex, and assumes that it's useful to categorize the world of software in terms of "things" before you can use them.  Ultimately we end up trying to resolve unnatural and impossible mappings such as OO-Relational and OO-XML, which creates even more difficulties. 
 
Software tools need to improve the level of abstraction, not introduce additional complexities.  The purpose of software is to allow humans to tell computers what to do, and it therefore needs to be as simple and natural as possible.  Objects are counter-intuitive since computers are all about executing functions (i.e. it all boils down to CPU instructions), as are businesses for that matter.  MDA and UML do not really help  since they expect us to first learn how to reinterpret the world of functions into objects with methods.  As you said you can definitely create services this way but I would personally prefer to see better tools for developing services natively than try to retrofit SO into OO based systems.
 
We could have another interesting discussion here about whether or not pictures help.  I am not sure they really do.  At least not alone.  It isn't possible to express completely in graphics what instructions you want the computer to execute.
 
Eric

 
----- Original Message ----
From: Stefan Tilkov <[EMAIL PROTECTED]>
To: [email protected]
Sent: Thursday, August 17, 2006 4:34:02 AM
Subject: Re: [service-orientated-architecture] John on Gartner, AJAX & Assorted TLAs

Eric, I remember us having this discussion a couple of years ago ...

First of all, MDA is not necessarily based on UML, it can also be
used with MOF. For example, Eclipse's EMF, which contains an
implementation of EMOF, can be used to build domain specific modeling
languages that are not object oriented. These can then become part of
an automated tool chain that would clearly qualify as "MDA
compliant" (although there is no such thing).

Secondly, it's perfectly possible to use UML to model services. You
model classes, including attributes and associations, and specify
them as types for the single parameter in service classes' method
signatures. What's not service-oriented about this?

Thirdly, what's the (simpler) modeling alternative you suggest?

MDA, or in fact any form of model-driven software development, has
many pros and cons. There's also a lot to be said against UML (e.g.
its complexity and number of features which are largely unused in
practice); its OO features are, IMO, definitely not a problem for
applying it to SOA, though.

Stefan
--
Stefan Tilkov, http://www.innoq. com/blog/ st/

On Aug 16, 2006, at 4:24 PM, Eric Newcomer wrote:

>
> I just want to point out that MDA is not a good fit for SOA since
> it's based on UML, which is object-oriented, not service oriented.
>
> UML has some value for whiteboarding and design, but in general OO
> analysis and design is overly complex for SO.
>
> Regards,
>
> Eric
>
> ----- Original Message ----
> From: Gervas Douglas <gervas.douglas@ gmail.com>
> To: service-orientated- architecture@ yahoogroups. com
> Sent: Monday, August 14, 2006 2:56:32 PM
> Subject: [service-orientated -architecture] John on Gartner, AJAX &
> Assorted TLAs
>
> <<Model-driven and event-driven architectures are two technologies
> expected to have a big impact on developers over the next decade. And
> while many IT professionals are in the dark about much of Gartner's
> "Hype Cycle for Emerging Technologies, " these architectures, along
> with AJAX apps, have very bright futures.
>
> The Gartner report released last week includes an analysis of 36
> technologies and trends that are expected to mature within the next 10
> years in a five-step process Gartner calls the "hype cycle."
>
> Emerging trends begin at the "technology trigger" stage with a product
> launch, move on to the "peak of inflated expectations" stage thanks to
> media-generated buzz, then advance to the "trough of disillusionment"
> period when the technology fails to meet developers' expectations,
> proceeds to the "slope of enlightenment" phase when IT professionals
> continue to experiment and apply the technology despite the decline in
> media coverage, and finally peak at the "plateau of productivity"
> stage, as the industry absorbs and accepts its advantages. And the
> increasing popularity of SOA is responsible for these emerging
> technologies.
>
> "SOA&#9472;that' s the current big wave that everyone needs to be
> aware of
> and tapped into," said Jackie Fenn, Gartner fellow and creator of the
> hype cycle.
>
> While Fenn explains that some enterprises have already begun
> implementing service-oriented architectures, many have yet to explore
> migration of their event-driven and model-driven apps to SOA. But that
> will likely change. "We think this is becoming a hyped and focused-on
> approach."
>
> Event-driven architecture (EDA) is a common style for distributed apps
> that are typically designed into modular, encapsulated, shareable
> components with event services. The services can be created through an
> app, an adapter or agent acting non-invasively. According to the
> report, those in the financial trading, energy trading,
> telecommunications and fraud detection industries have begun using EDA
> technology, along with the Department of Homeland Security. But
> Gartner says EDA is at least five years from mainstream maturity.
>
> As for Model-driven architecture (MDA), a technology from the Object
> Management Group, the process will turn the heads of developers simply
> for its increased flexibility through SOA. The technology
> distinguishes biz-level functionality from the technical complexity of
> its implementation, enabling the apps to be modeled by standards like
> Unified Modeling Language. This allows the models to operate free from
> potential platform limitations and instantiate them into specific
> runtime implementations using a target platform of choice. Fenn says
> both MDAs and EDAs will find their niche with developers largely
> thanks to SOA and their bottom-line boosting perks.
>
> And Fenn says a third "high impact" technology, AJAX, will soon enough
> prove influential to the dev lifecycle and should reach maturity
> within the next two years.
>
> "AJAX gives you that more responsive user experience in the browser
> environment, " Fenn says.
>
> The Web 2.0 technology is a combination of processes that developers
> use to increase functionality for their end users, metamorphosing a
> limited and frustrating Web app into a more readable service. While
> the improvements may not be extreme, the report says AJAX apps have
> the ability to raise bottom lines by enhancing the user-friendliness
> and reliability of such Web apps.
>
> The "Hype Cycle for Emerging Technologies 2006" is one of 78 `hype
> cycle' reports Gartner released this year. The report evaluated nearly
> 2,000 information technologies and trends among more than 75
> industries. Gartner analysts reviewed and debated each technology
> within a "cross-industry view," rating performance, services and how
> each technology will impact an org's bottom line.
>
> According to Fenn, those emerging technologies deemed "high impact"
> will pay the biggest dividends for businesses over the next decade.
> But while each trend's maturity rate remains constant, she cautions
> that each technology's benefits will vary throughout industries.
>
> "Be selectively aggressive&# 9472;identify which technologies could
> benefit
> your business, and evaluate them earlier in the hype cycle," she says.
> "For technologies that will have a lower impact on your business, let
> others learn the difficult lessons, and adopt the technologies when
> they are more mature.">>
>
> You can find this at:
>
> http://www.adtmag. com/article. aspx?id=19054
>
> Gervas
>
>
>
>
>


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