Feeds

Sequence diagramming that's fit for purpose

Illustrate your point

High performance access to file storage

Book extract, part 4 In this, the final part of our series of experts from Use Case Driven Object Modeling with UML: Theory and Practice Matt Stephens and Doug Rosenberg show you how to draw lean, purposeful sequence diagrams that are driven from the use cases and preliminary design.

As before, this chapter opens with the following "you are here" diagram of the ICONIX Process, showing in red the area about to be covered.

Iconix Process sequence diagram

Mapping sequence and behavior

All the steps in the process so far have been preparing the use cases for the detailed design activity. By this time, your use case text should be complete, correct, detailed, and explicit. In short, your use cases should be in a state where you can create a detailed design from them.

If you figure that preliminary design is all about object discovery, then detailed design is, by contrast, about behavior allocation - that is, allocating the software functions you've identified into the set of classes you discovered during preliminary design.

When you draw sequence diagrams, you're taking another sweep through the preliminary design, adding in detail. You use sequence diagrams to drive the detailed design. We advocate drawing your sequence diagrams in a minimal style.

Here is our final 10-point checklist for successful sequence diagramming. As with all our lists, pay attention because there will be questions:

Top 10 sequence diagramming guidelines

10. Clean up the static model before proceeding to the next step

9. "Prefactor" your design on sequence diagrams before coding

8. Review your class diagrams frequently while you're assigning operations to classes, to make sure all the operations are on the appropriate classes

7. Assign operations to classes while drawing messages. Most visual modeling tools support this capability

6. Don't spend too much time worrying about focus of control

5. Make sure your use case text maps to the messages being passed on the sequence diagram. Try to line up the text and message arrows.

4. Use the sequence diagram to show how the behavior of the use case is accomplished by the objects

3. Start your sequence diagram from the boundary classes, entity classes, actors, and use case text that result from robustness analysis

2. Do a sequence diagram for every use case, with both basic and alternate courses on the same diagram

1. Understand why you're drawing a sequence diagram, to get the most out of it

High performance access to file storage

More from The Register

next story
Windows 8.1, which you probably haven't upgraded to yet, ALREADY OBSOLETE
Pre-Update versions of new Windows version will no longer support patches
Android engineer: We DIDN'T copy Apple OR follow Samsung's orders
Veep testifies for Samsung during Apple patent trial
OpenSSL Heartbleed: Bloody nose for open-source bleeding hearts
Bloke behind the cockup says not enough people are helping crucial crypto project
Microsoft lobs pre-release Windows Phone 8.1 at devs who dare
App makers can load it before anyone else, but if they do they're stuck with it
Half of Twitter's 'active users' are SILENT STALKERS
Nearly 50% have NEVER tweeted a word
Windows XP still has 27 per cent market share on its deathbed
Windows 7 making some gains on XP Death Day
Internet-of-stuff startup dumps NoSQL for ... SQL?
NoSQL taste great at first but lacks proper nutrients, says startup cloud whiz
US taxman blows Win XP deadline, must now spend millions on custom support
Gov't IT likened to 'a Model T with a lot of things on top of it'
prev story

Whitepapers

Mainstay ROI - Does application security pay?
In this whitepaper learn how you and your enterprise might benefit from better software security.
Five 3D headsets to be won!
We were so impressed by the Durovis Dive headset we’ve asked the company to give some away to Reg readers.
3 Big data security analytics techniques
Applying these Big Data security analytics techniques can help you make your business safer by detecting attacks early, before significant damage is done.
The benefits of software based PBX
Why you should break free from your proprietary PBX and how to leverage your existing server hardware.
Mobile application security study
Download this report to see the alarming realities regarding the sheer number of applications vulnerable to attack, as well as the most common and easily addressable vulnerability errors.