1
Review of UML
The purpose of this chapter is to set the scene by reviewing the key UML concepts, the main diagram types, and the role of those diagrams within the software development process. If you're quite new to
UML this will serve as a practical introduction that will help you make sense of the rest of the book, before you move on to further reading. If you're experienced with UML the chapter will serve as handy revision and you might just find some nuggets of information that have so far eluded you.
Either way we'll all be moving on from roughly the same starting point: with the same appreciation of
UML notation, with an understanding of relevant software development processes, and with a common bias towards .NET and the Visio for Enterprise Architects tool.
The final point is quite important, and the raison d'être for this book. In recent years the body of UML literature has focused mainly on Java development and the use of modeling tools such as Rational Rose.
In this book we're applying a .NET development perspective at the same time as demonstrating the so far under-documented Visio modeling tool that comes bundled with the Visual Studio .NET
Enterprise Architect.
With all this in mind we can now press on with the introduction to – or revision of, depending on your background – the Unified Modeling Language.

What is the Unified Modeling Language?
When discussing UML, we need to establish one important point right up front.
The Unified Modeling Language is a notation ; that is a set of diagrams and diagram elements that may be arranged to describe the design of a software system. UML is not a p rocess, nor is it a method comprising a notation and a process.

Chapter 1

In theory you can apply aspects of the notation according to the steps prescribed by any process that you care to choose – traditional waterfall, extreme