2.1 Basic Software Fortress Diagram

The basic picture of a software fortress is somewhat similar to the UML class diagram. The software fortress version uses a double-lined box to indicate the fortress itself. Drawbridges are indicated either by single-lined boxes or, in some diagrams, by labeled arrows entering the fortress. Rather than use a cartoon figure to indicate the type of the fortress (such as the Viking to represent the business application fortress), I give the name of the fortress followed by a double colon followed by the fortress type (e.g., presentation).

Several features are conspicuously missing from the fortress diagram. For example, there is no diagrammatic counterpart to the guard, the envoy, or the strongbox, all of which are assumed to be present. Unlike a UML class diagram, the fortress diagram does not include the interface to the fortress. The interface to the fortress is equivalent to the drawbridge, which, at the fortress level, is complex enough to require a specialized documentation technique, which I will discuss shortly.

Figure 2.1 shows a diagrammatic representation of a business application fortress, contrasting it to its cartoon counterpart.

Figure 2.1. A Sample Software Fortress Diagram