This appendix presents a brief introduction to UML notation as used in the book. For more detailed discussion of UML, its history, notation, documentation, and uses, the reader is referred to the UML Web page for Rational Software Corporation:

http://www.rational.com/uml/

Representing Classes in UML

UML notation provides a rich variety of options for graphically representing the details of a class. The basic icon for a class is a rectangular box with one, two, or three compartments as shown in Figure A.1. The compartments contain strings and special symbols. The Name compartment is required. The two List compartments typically contain attributes and operations and may be suppressed as desired. Within each compartment, UML offers many options for amount of detail to be shown.

Among the options for detail to be shown in the three compartments are the following:

• String – an identifier representing a class name, field name, or method name.

• ≪stereotype-string≫ – A string in guillemets is a stereotype. Stereotypes may be thought of as categories that further qualify a class, field, or method. For example, we may use the stereotype «interface» to identify a class that is a Java interface. We may apply the stereotype «final» to a constant field and the stereotypes «command» or «query» to methods.

• +, -, # - Visibility is indicated using a “+” symbol for public, a. “-” symbol for private, a “#” symbol for protected, or no symbol for package (Java default). […]