Inconvenient Accessibility Makes Self-Documenting Code

Intentional use of access modifiers (public, private, etc.) is like a clear memo to your team. This came up during Steve Bohlen's Virtual Alt.Net talk on domain-driven design.

Steve explained the distinction between Entity objects, which have a unique identity independent of their properties (Even when I change my name, I'm still me.), and Value objects, which are defined by their properties (If you change the house number in an address, you have a new address.). When dealing with Entities, code should not be able to change the unique id—that would be like someone claiming your social security number and thereby becoming you. Therefore, Entity classes should have private setters for their unique identifiers.

A meeting attendee asked why, since this gets inconvenient when you're creating an object based on a record fetched from the persistence repository. It's a big pain; why bother? The analogy I would offer is this. When you're defining a class to represent an Entity in your business domain, you know it's an Entity. You intend for it to behave and be treated like an Entity. You don't want any of your teammates setting its unique id in their code. So you send them an email: "Don't set Person.UniqueId, okay?" Uh hunh. How well is that going to work over time?

Instead, if you simply don't provide a public accessor to the UniqueId property, your teammates will get the message loud and clear. Granted, someone could edit the code and change the accessibility, but the fact that he or she needs to is a flashing neon sign saying "Stop. Think. Are you barking up the wrong tree?" You've made your code communicative. Its structure conveys your intent. No need for comments; this is an example of self-documenting code.

Follow-up to the Retrospectives Workshop

My co-facilitator Suzy wrote up her reflections from the AgileAustin retrospectives workshop, where she shares more of the great insights that came from the participants.

Retrospectives: Collaborative Improvement

Suzy Bates and I facilitated an AgileAustin workshop this morning called "Cheaper Than an Off-Site: How to hold effective retrospectives that improve team collaboration and performance." It was absolutely a blast, from planning through delivery. A benefit I didn't anticipate (but should have) is that I learned a lot, myself. I'll share some of those epiphanies here.

If you were to ask me what one thing a team could do to improve its delivery of great software on a predictable schedule, I would say: hold effective retrospectives. A retrospective is a regularly recurring discussion where the team reflects on how they work together, and what they will change in order to get better. The end of a sprint, right after the demo, is a good time for this.

We presented the following as the key ideas:

1. Safety
2. Diversity of viewpoints
3. Collective ownership
4. Structured discussion

Being a facilitator for the workshop was a bunch of fun. Collaborating with Suzy was excellent—meshing our two approaches really enhanced the content, as I brought the philosophy and she brought the practical hands-on exercises, and we kept each other moving and making progress on our preparations. If you're tempted to lead a workshop but daunted, find a teammate.

The audience participation was even richer than I'd hoped. People enthusiastically contributed, leapt into the exercises with gusto, and shared some striking insights. I learned neat stuff. Here are some highlights:

• Rotate who holds the role of retrospective leader (or sponsor). That brings fresh ideas and spreads the sense of shared ownership.


• When a team member expresses dissatisfaction (for example, through a team satisfaction histogram), sometimes it is appropriate to acknowledge it without delving into why and root cause and solutions. If team safety means I can say how I feel and that's okay, then I should be able to say how I feel without getting interrogated about why I feel that way.


• A bunch of "went well" items without any "needs fixing" items might indicate a lack of team safety. In today's exercise, our sprint teams barely knew each other, so they wanted to be polite, and so they were very positive in their reflections. When you're comfortable with your team and trust them, it becomes easier to talk about areas for improvement. I'd view a series of "everything was great" sessions as indicative of a lurking problem.


• Affirmative Inquiry is a philosophy/strategy worth looking into. It replaces, for example, the negative "why is this broken" by changing it into a positive "what was successful in the past that we could apply here."


• Book recommendation for Jim Highsmith's work (probably Agile Project Management?).

If you attended the workshop: Thanks! It rocked. If you weren't able to, keep an eye out for future AgileAustin workshops. They're announced on the AgileAustin email list, so sign up for that. If you don't live in Austin, well... nanny nanny boo boo.