Creating a Use Case System

A use case system defines a system analysis' subject matter with regards to the services offered by the system to the outside.

Context

A use case system combines several use cases. It represents the border between the use cases and the environment and describes the scope of the modeled area.

In the use case diagram, a system is represented by a rectangle. The actors, who/which interact with the system, are located outside this rectangle, while the use cases, which represent the possible interactions with the system, are contained within the rectangle.

You can use various systems in use case diagrams at the same time; they can also be nested. This enables e.g. clear structure of subsystems.

According to the UML specification, every classifier can realize a use case. This is why various icons for a use case system are available; these provide various classifiers spanning all systems.

The configuration sets whether a classifier can only contain other systems and/or use cases as a use case system.

You cannot drag a use case system over a set of use cases at a later stage. For this reason, you should start with the use case system and assign use cases to it.

How to proceed

Position the mouse pointer where you want in the diagram.
Click the right mouse button and click on one of the following icons in the context menu's mini toolbar:

Component (Use Case System)

Class (Use Case System)

Interface (Use Case System)

Node (Use Case System)

Device (Use Case System)

Execution Environment (Use Case System)

Artifact (Use Case System)

The use case system is created and is given a default name. You can immediately change this.
To create nested use case systems, place the mouse pointer on the use case system that you want to nest; click the right mouse button and then, in the mini toolbar of the context menu, click on the desired icon of a use case system.