There are 13 different diagrams defined in the UML 2.0 standard (Up from 9 in UML 1.0.) They can be divided into six structure diagrams and seven behavior diagrams. Very few people ever attempt to use all of them. The goal should be to use diagrams where they make sense and to avoid being confused by them when they don't.
In the Visual Basic .NET 2005 Express tutorial, I develop several versions of the Signature Block program, but there's no UML analysis of the program there because that tutorial is, "a course in programming rather than analysis and design." Here, the emphasis is on analysis and design, so let's see what some of them might look like starting with the structure oriented diagrams.
- Class Diagrams
Class diagrams, which capture the programming classes that make up the UML model, are probably the ones that programmers will see more than others because these diagrams can relate directly to what the programmer does. These diagrams show the name of the class and the methods and properties (called behaviors and attributes in UML diagrams).
Using Visio, I manually created what seemed to me to be an appropriate class diagram for the SigBlock program from part 6 of the Visual Basic .NET 2005 Express:
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I also reverse-engineered the program into UML using the Visual UML modeling tool. Here's what that turned out to look like:
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I felt pretty good when my diagram turned out to be mostly the same as the reverse-engineered diagram from Visual UML! Visual UML is a better tool for VB.NET programmers than tools like Objecteering because it directly supports Visual Basic and .NET.
The other structure oriented diagrams (UML 2.0) are:
- Component Diagrams
Describes the organization of physical software components. The symbols used on these diagrams don't relate very well to the symbols you see in Visual Studio or VB Express.
- Object Diagrams
Object diagrams describe the static structure of a system.
- Composite Structure
Shows the internal structure of a class.
- Deployment Diagrams
The physical resources in a system.
- Package Diagrams
A subset of class diagrams, they organize elements of a system into related groups.
The rest of UML describes what a system does rather than what it is. On the next page, we look at that.
