UML Weekend Crash Course™ - To Parent Directory

Session 1—What Is the UML 9
they are all used in the construction of a user interface. But, as Figure 1-3 shows, the individual
classes could be as diverse as Frame, Button, and DropDownList.
Frame
Button
DropDownList
Figure 1-3 A stereotype on a class
There are a number of stereotypes already defined in the UML, but you are free to
define and use your own. The existing stereotypes are specified in Appendix A of the UML
specification.
Because no notation can cover every possible type of information, the UML also supports
the use of comments. Figure 1-4 illustrates a sample comment icon. You may place as much
text as needed within the symbol. The symbol can be placed anywhere on any diagram.
Place your comment
inside this figure
Figure 1-4 Comment notation
Another extension, called a constraint, is used throughout the UML diagrams to limit the
use of a model element. You can always spot constraints by the use of { } braces around the
text that describes the limitation you want to impose. For example, you might want to limit
the values that can be used for the attribute “age” to between 21 and 120. The constraint
might look like this: {age > 20 and < 121}. I’ll cover the use of constraints with each diagram
in the subsequent sessions.
There are two more mechanisms that reach beyond the scope of an introductory book,
tagged values and profiles. A complete description is available in the UML specification.
Ten Diagrams
Ten diagrams are defined in the UML metamodel. Each is fully described using Class diagrams
and textual narrative. A key to the successful application of the UML is in understanding
that you can use the notation standard with any number of different development methods,
process controls, and quality controls.
In Session 2, I explain the difference between a process and the UML, how they complement
one another, and four very different yet popular processes to apply the UML. Session 3
provides an overview of the diagrams. The rest of this course is devoted to explaining the
purpose and definition of each UML diagram and their relationships to one another. This
understanding should prepare you to apply the models successfully in your own unique
environment.