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In our last episode, The Reader (inspired by his UML book), The UML Guy, and a small army of guest stars drew an Activity Diagram to get Traveler back... to the 80s! That led to some good comments from Mitch and Corey, along with a lot of blather from The UML Guy.

Now they examine the results of their work. But what's happening with The Reader's book?

(Click the pictures for larger images.)

Episode 14a

 Episode 14b

OK, so why the weird title for this episode?

Well, I needed to introduce Superactivities and Subactivities before the next episode. The diagrams I'm planning would be just too complex without them. Plus it's plainly an important technique for The Reader to learn before tackling any really complex Activity Diagrams. So I needed an episode between the last episode and the next one.

And sure enough, the films that inspired this arc are a trilogy. That means I could use a third film, right? Wrong! See, I know what I have planned for the next episode, and it's clearly 100% based on the second film. (If the hints in this episode didn't tell you that, you must not know the films. And sorry, Mad Dog fans, but I probably won't use the third film. I haven't seen anything new I can teach with that film.)

So I needed something between film 1 and film 2. The obvious answer would be an intermission; but I've already established that Intermissions in the Lounge are for meta issues like the schedule or the Web site. So I tried to think of something else that fit; and as I did, this song kept running through my head. And thus, an episode title was born!

Other than that, I hope this episode needs little commentary. Breaking your Activity Diagrams into Superactivities is a simple yet powerful way to organize your plans and processes. Some people even start with Superactivities, and then drill down to add detail; but while I see merit in that approach, it doesn't come naturally to me. What works best for me always seems to be the process captured in Episode 13 and this episode put together:

  1. Lay out the Happy Path of a few simple steps.
  2. Play the What Could Go Wrong Game, identifying possible faults and exceptions at each step in the Happy Path and in the exception paths, ending up with a complex but complete plan or process.
  3. Group the Activities and Branches from step 2 into Superactivities. Sometimes these Superactivities will look very close to the Happy Path from step 1; but usually I end up with some major Branches and Activities that we never thought of in our first step.

It's a sloppy process, but I always seem to learn something along the way.

And as @anklebuster is sure to note, there's something missing from Episode 12: we've lost the Spacetime Continuum! But that's, like, everywhere! Oh, noooo! I feel a song coming on!

I've got nowhere to run
Nowhere to hide
No way to stop
This hurt deep inside
That you gave to me
Nowhere to run
Nowhere to run
Nowhere to run

Well, we haven't really lost it. (How do you lose a place? Especially, how do you lose the place where all places are found?) But I decided it was cluttering up these diagrams. It still adds value to the discussion, but not more value than we lose from the clutter. The only place it's relevant in the major diagram is at the Branch after Planning. I think we can assume that when we reach that Branch, everyone will understand the question without us explicitly showing the Object. (In a production system, I would add a detail diagram for each Superactivity from page 2; and in those detail diagrams, Spacetime Continuum would appear where it made sense.)

Posted on Saturday, November 15, 2008 5:00 PM Ulterior Motive Lounge | Back to top

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