* Posts by David Daly

5 publicly visible posts • joined 21 Aug 2007

Tools vendors stuck on UML and agility

David Daly

UML Can Be Useful

I have to agree with Nat Pryce here - UML does not prove that your software will work. You can’t find a bug in your UML and you can’t create UML that can be compiled and that an end user can test. Sometimes I think that is what attracts people to it! I said as much in my post on Effective UML (http://outofthetriangle.wordpress.com/2007/10/06/effective-uml/) as well as listing what you can do to make sure the UML you produce is useful.

David Daly

Ditch tools and write your UML by hand

Whilst I accept that UML tools could be better I have to agree with James Richardson when he says “UML should be kept on the whiteboard”. Fleshing out a high level design (which is surely what UML good for) is often best done in a group session with all your diagramming being done by hand on a whiteboard. One of the reasons this doesn’t happen, in my experience, is that people don’t learn to “write” UML. Instead they see a need for a tool before they can produce anything. Kind of like being able to type but not write anything by hand. When I learned UML (see my post http://outofthetriangle.wordpress.com/2007/07/25/learning-uml/) I spent some time practicing drawing diagrams by hand.

Why UML won't save your project

David Daly

Diagrams must simplify to be useful

Not only do I agree that drawing exhaustive diagrams of an existing poor design is not useful, I would add that too much detail at any stage reduces the value of a diagram. I recently posted 3 rules for effective UML at http://outofthetriangle.wordpress.com/2007/10/06/effective-uml/ and one of them is “Keep it simple”.

Having said that, a diagram that gives a simplified view of an existing system and highlights specific design flaws can be a good starting point for a re-design in some circumstances (even if only as part of a business justification for a total re-design!).

Persona analysis

David Daly

Sounds like a useful technique

One team I worked on decided to include relevant use cases within technical designs in order to keep developers (me included) aware of how their part of the application would actually be used (more on this in my blog post http://outofthetriangle.wordpress.com/2007/07/25/learning-uml/. Persona analysis sounds to me like another good way of giving context to the development of an application.

In the beginning, there was the flowchart...

David Daly

Agree that state diagrams are useful

I recently blogged (at http://outofthetriangle.wordpress.com/2007/07/25/learning-uml/) about finding state diagrams to be one of the most useful parts of UML and I’m pleased to see that I’m not the only one that feels this way. I also agree that, beyond a certain level of detail, diagrams cease to be useful as you might as well write code!