recent posts related to object oriented design and programming

The best UML “Use Case” definition I know

Every time I read an article or book about UML “Use Cases” I cringe a little bit. Every author says something like “Jacobson left the definition of a Use Case too open,” and then they try to work through some elaborate scheme of what a Use Case means to them. IMHO, the best use case definition was created in the early 1980s, long before Jacobson mentioned the term.

UML sequence diagram - how to show a web service call

I recently started to model an application that makes extensive use of web service calls, and my customer asked me to include a UML sequence diagram to show the flow of calls in the system. This prompted me to wonder, "What is the correct way to show distributed systems (like a web service) in a UML sequence diagram?"

If this link is correct, in a UML diagram you show remote systems as actors.

UML use case diagram - visually show processes

Question: Is there a UML diagram to visually show the processes in a system?

Yes, you can use use case diagrams to represent the use cases (processes) in a software system. Use case diagrams show the actors in a system, and the ways in which these actors use the system.

This is why I use the terms "use cases" and "processes" interchangeably. IMHO, "use case" is a fancy way of saying "process", or perhaps more accurately, user-initiated processes, or event-driven processes.


Use Case UI tip - Keep UI assumptions out of Use Cases

I ran into the perfect situation this week that defines why you should not put UI assumptions in Use Case (or task) documentation. A customer decided that they really wanted to change a UI from the proposed tabular approach (with potential popup windows) to a tree view. If the use case mentions things like "double-click", "press OK", and UI phrases of that nature, the use cases would need to be re-written. Without those UI assumptions they should be fine.

OOA/OOP Koan: No end user

OO Koan: You are assigned to work on a project, but you cannot communicate with the end user -- how do you develop the software?

(Answer: Lots of luck. ;)