Imagine a typical use case you would execute on Amazon such as going to the Amazon site, be it UK, USA, FR, whatever, and then on the homepage entering a title for a book you want to look up, say ‘Java’, and then submitting the query. You get a results page and you look through the list and click on one of the books that looks likely to be the one you want and go to the books’ details page. That a typical use case that I perform quite often and I am sure many of you do to so, how do we represent this as a robustness diagram? Well, first, I would write a more fully fledged use case and then work out the boundary, control and entity objects as best I could from there. Next. I wouldwork through the usecase steps and start building the robustness diagram.

Now, I am not going to write a verbose use case as you and I have performed this umpteen times and should  know it like the back of our hands. Also, I just bought a few bottles of Wells Banana Bread Beer and  it’s nearly lunchtime, but i fancy my elevensies so, in short, not gonna write the use case. However, here  is the resulting robustness diagram that I have constrcuted. Remember, it is a first pass, may need  refinement, but it shows the main element.

Robustness analysis diagrams like all notations have rules associated with them. Violating these rules creates conflicts and the diagram will not ‘read’ well. The robustness analysis rules are the following: -

• Actor objects cannot interact with other actors.
• Actor objects cannot interact with control objects.
• Boundary objects cannot interact with other boundary objects.
• Entity objects cannot interact with other entity objects.
• Entity objects cannot interact with control objects.
• Control objects cannot interact with other actor objects.

A glass of Old Speckled Hen to accompany me, I am writing my first post on my newly created blog, Agile Systems Architect (Old Specked Hen is recommended whilst reading  ). So, this blog has been created with the intention on providing some insight into what an Agile Systems Architect does and how he/she goes about doing it. The other reason to create this blog is to post information for myself and friends so that we have it for reference. Yes, I know, we could use a wiki but we thought that this would be more fun. Ok, nuff said about the first post, back to the Old Speckled Hen.