Tag Archives: structured design

Musings of an OOPSLA elder

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I don’t think of myself as an “elder”. But that is what Linda Rising, who led the 20th OOPSLA retrospective, labeled those who were at the first OOPSLA. I am one of five who received a perfect attendance ribbon (Allen Wirfs-Brock, Brian Foote, Ralph Johnson and Ed Gehringer are the others) for having attended all OOPSLAs. At the very first OOPSLA I felt like an outsider. I wondered how I could get involved with this conference. Excitement was in the air. Objects were the next big idea. Just exactly what could I do that would have an impact? My paper on Color Smalltalk was rejected (the reviewers’ commented that it talked too much about hardware details) so I presented it as a poster. It was good that they rejected it. Our work was premature. Three years later, when Tektronix Color Smalltalk was finally a product, I wrote a paper about the design principles and class libraries in Color Smalltalk that was accepted. This success made me believe in my writing abilityand led to my paper with Brian Wilkerson on Responsibility-Driven Design in 1990, and launched my enduring interest in design.

Thursday I had another elder moment. I was on a panel with Ed Yourdon, Larry Constantine, Grady Booch, Kent Beck, and Brian Henderson-Sellers that looked back at echoes of the past and structured design and into the future. Larry Constantine provoked us to bring theory, technique and transparent tools into all we do. Kent brought the house down by quoting from Structured Design. He noted that while Ed and Larry got a lot right, they missed out on the fact that systems need to change. Refactoring wasn’t part of Ed and Larry’s vocabulary. Ed, who has been an expert witness on software cases for the past few years, noted that there often isn’t even a shred of a plan or design or any documentation for software systems. Grady mentioned that increasing abstractions have been a big factor and challenged us to move to even further levels of abstraction. More down to earth, I spoke about how objects enabled me to think clearly, and that the power of abstraction, encapsulation, and thinking in terms of small neighborhoods of collaborating, responsible objects as a big step forward. What’s next? To me, it seems that even more effective methods and practices, powerful development and testing environments, expressive languages, patterns, and thinking tools are in our future. Innovation in our industry is a constant. Yet every once in a while it is good to reflect on what we got right and remember influences from the past. But I’m forward looking too. After every OOPSLA I come home charged with new ideas and the urge to do more, collaborate, and continue learning. What a blast!

Why Objects?

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As I’ve been working on a position statement for an OOPSLA panel reflecting on the roots of modern software development practices while looking to the future, I’ve been thinking hard about why I got hooked on object technology. Compared with structured programming and design, objects seemed significantly better at handling complexity. Object programming languages were an earth shattering improvement over the procedural and assembly languages I used when I first encountered structured design techniques. Instead of simply following conventions, object programming language constructs forced me to bundle together meaningful operation and data. Object-oriented methodologies generally incorporate the principles of structured design but OOD seems much more than an incremental improvement over SD. Instead of focusing on a thread of control and managing its complexity via procedural decomposition and structured control constructs, object design enables me to break a composition into thousands of semi-autonomous entities with structured roles and responsibilities. Objects offer me a completely different way to think about computation. This way of thinking empowers me to deal with a level complexity that I could never have dealt with only using structured design techniques. Object technology encourages me to form abstractions—objects—and to design how small neighborhoods of them interact.

Responsibility-driven design offers thinking tools that enable developers to conceive of an implementation in terms of interacting roles and their responsibilities. It provides a vocabulary for describing designs that helps developers communicate complex ideas and make tradeoffs more effectively. Agile practices, by emphasizing working code that satisfies customers, seek to reduce accidental complexity by admonishing you to design simply and grow complexity only when needed. Eric Evans, in Doman-Driven Design: Tackling Complexity in the Heart of Software, offers tactics for identifying, preserving, and sharing a common domain model. Refactoring tools have taken tediousness out of making changes and modern application development environments have made it possible for development teams to “hum” by testing and building incrementally. These all represent progress.

But at the end of the day, they cannot reduce the complexity inherent using diverse tools, platforms, and technologies that make up a typical sprawling IT system. While OOD/OOP did give us an order of magnitude improvement over previous techniques and tools, we still don’t have the order-of-magnitude better approach we need to sort today’s complex environments and minimize the gaps and seams that are inherent when diverse technology comes together in a complex system. In the meantime, thank goodness for the framework builders who give us various ways of linking objects with relational databases and for little languages and tools that take the tedium out of repetitive (error prone) tasks of gluing things together. We live in a complex world where objects will continue to make a lasting, significant contribution. What will be the next breakthrough in software development that will subsume the principles of OOD (and transitively SD) and provide the next order of magnitude improvement? I’m not sure. While I don’t think there are any silver bullets out there, I look forward to discovering and encountering even more effective practices, technologies, and techniques that allow us to address inherent complexity head on.