SOA Benefits: Too Much Reuse of Reuse?

Ever since the dawning of structured software development, arguments have been put forth that, if we only architected [fill in the blank] entity relationships, objects, components, processes, or services, software development organizations would magically grow more productive because they could now systematically reuse their work. The fact that reuse has been such a holy grail for so many years reveals how elusive it has always been.

And so Joe McKendrick summarized the recent spate of arguments over SOA and reuse quite succinctly this morning: “What if you built a service-oriented architecture and nothing got reused? Is it still of value to the business, or is it a flop?” The latest spate of discussions were sparked by a recent AMR Research report that stated that too much of the justification for SOA projects was being driven by reuse. McKendrick cited ZapThink’s David Linthicum, who curtly responded that he’s already “been down this road, several times in fact,” adding that “The core issue is that reuse, as a notion, is not core to the value of SOA…never has, never will.” Instead, he pointed to agility as the real driver for SOA.

To give you an idea of how long this topic has been bandied about, we point to an article that we wrote for the old Software Magazine back in January 1997, where we quoted a Gartner analyst who predicted that by 2000, at least 60% of all new software applications would be built from components, reusable, self-contained pieces of software which perform generic functions.

And in the course of our research, we had the chance to speak with an enterprise architect on two occasions – in 1997 and again last year – who was still with the same organization (a near miracle in this era of rapid turnover). A decade ago, her organization embraced component-based development to the point of changing job roles in the software development organization:
Architects, who have the big picture, with knowledge of technology architecture, the requirements of the business, and where the functionality gaps are. They work with business analysts in handling requirements analysis.
Provisioners, who perform analysis and coding of software components. They handle horizontal issues such as how to design complex queries and optimize database reads.
Assemblers, who are the equivalent of developers. As the label implies, they are the ones who physically put the pieces together.

So how did that reorg of 1997 sink in? The EA admitted that it took several reorgs for the new division of labor to sink in, and after that, was adjusted for reality. “When you had multiple projects, scheduling conflicts often arose. It turned out that you needed dedicated project teams that worked with each other rather than pools. You couldn’t just throw people into different projects that called for assemblers.”

And even with a revamping of roles, the goals of reuse also adjusted for reality. You didn’t get exact reuse, because components – now services – tended to evolve over time. At best, that component or service that you developed became a starting point, but not a goal.

So as we see it, there are several hurdles here.

The first is culture. Like any technical, engineering oriented profession, developers pride themselves in creativity and cleverness, and consider it un-macho to reuse somebody else’s work – because of the implication that they cannot improve on it.

Secondly is technology and the laws of competition.
1. During the days of CASE, conventional wisdom was that we could reuse key processes around the enterprise if we adequately modeled the data.
2. We eventually realized that entity relationships did not adequately address business logic, so we eventually went to objects, followed by coarser grained components, with the idea that if we built that galactic enterprise repository in the sky, that software functionality could be harvested like low hanging fruit.
3. Then we realized the futility of grand enterprise modeling schemes, because the pace of change in modern economies meant that any enterprise model would become obsolete the moment it was created. And so we pursued SOA, with the idea that we could compose and dynamically orchestrate our way to agility.
4. Unfortunately, as that concept was a bit difficult to digest (add moving parts to any enterprise system, and you could make the audit and compliance folks nervous), we lazily fell back to that old warhorse: reuse.
5. The problem with reuse took a new twist. Maybe you could make services accessible, even declarative, to eliminate the messiness of integration. But you couldn’t easily eliminate the issue of context. Aside from extremely low value, low level commodity services like authentication, higher level business requirements are much more specific and hard to replicate.

What’s amazing is how the reuse argument continues to endure as we now try justifying SOA. You’d think that after 20 years, we’d finally start updating our arguments.

One thought on “SOA Benefits: Too Much Reuse of Reuse?”

  1. There’s perhaps something bleeding obvious I still want to point out. Not re-using other people’s code is more than just being culturally perceived as un-macho. As Brooks pointed out in his _The Mythical Man-Month_ (yes, book more than a little old, still relevant) is that making components reusable is more than abstracting out the functions a bit. You need good release engineering and even worse, good documentation. Most programmers can’t write documentation to save their lives.

    Then there’s the problem of using third-party libraries that turn out to come with interfaces designed by crackmonkeys, lots of funky bugs that get tickled any time you use the library outside of the non-documented use cases of the original application, lots of small and not-so-small compiler-specific, against-the-standard, and other silly issues, and so on and so forth, all beyond mere lack of engineering and documentation.

    You could argue this all falls under “culture”, but if so then there are identifyable technical aspects to it. I say it’s only half culture, the other being laws of physics. Or at least “laws of management”, which certainly makes it mostly a people problem, but not necessairily a cultural one.

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