ProductsUModelUML Use Case Diagrams

Use case diagrams are the starting point for UML-based software development projects. As you draw your first use case, you will immediately experience the user-friendly flexibility of Altova UModel® 2008.

There are two basic elements used in UML use case diagrams: the ellipse (or oval shape) and the actor. The ellipse contains a description of any person’s or thing’s specific interaction with the system under design. Additionally, it is sometimes used to represent subsequent system relationships. The actor characterizes the interacting person or thing.

You can create your use case ellipse from the toolbar or the right-click context menu. Either way, you will see entry helpers, fast editing buttons, and element characteristics to assist you. UModel® 2008 even automatically selects the name field so you can just start typing your own description. The ellipse will autosize to fit your identifier, or you can click and drag at any time to manually resize it.

Cascading styles permit you to change the fill color for use case ellipses either individually, in groups, or throughout the project. You can draw your own generalization, association, include, and extend relationship lines and position them manually by selecting from the use case toolbar, or you can grab the entry helpers that surround the ellipses. UModel® 2008 features fast editing buttons and specialized entry helpers for each supported UML diagram type. Roll your cursor over any helper or button to view a tool tip!

When you go back later to revise your UModel® 2008 use case diagram, the entry helpers and fast editing buttons reappear as you select the ellipse (or any other diagram element) again.

Along with the ellipse, the other major element of a use case diagram is the actor that interacts with the system. The traditional UML stick figure actor, descended from whiteboard brainstorming sessions, is simple to draw by hand, but alone, the basic stick figure is deficient in a modern UML application.

• The traditional stick figure does not scale well.
• The traditional stick figure does not accurately represent non-human actors. For instance, if your project is an auto navigation system, one of your actors might be a GPS satellite.
• The traditional stick figure does not visually differentiate the roles of various human actors such as a customer, a shipping clerk, or a payroll manager.
• The traditional stick figure could make an impression on non-programmers that your problem analysis is primitive, when it is actually very thorough.

In addition to introducing a new stick figure that can scale horizontally or vertically without forcing your actor to do calisthenics or a dancer’s split, UModel® 2008 also lets you assign your own images as symbols for your actors. You can use any of the images in the extensive library provided with UModel® 2008 or build your own set of .bmp illustrations to represent the various human roles and devices that are actors in your projects.

UModel® 2008 customized actors enhance your use case diagrams on screen and in printed documentation.

UModel® 2008 allows you to add hyperlinks to any element in any UML diagram, including use cases. Simply select an element, then choose the Hyperlinks option from the right-click context menu to open the Edit Hyperlinks dialog.

You can create hyperlinks to external files, to Web addresses, or to other diagrams in your project. For instance, you might want to add a hyperlink to your use case actor to cross-reference a user story or other requirements document.

Clicking the hyperlink in UModel conveniently opens the external file, diagram, or Web address.

The User defined name field in the Edit Hyperlinks dialog lets you enter a short, clear description of the hyperlink. Your description becomes pop-up text for the hyperlink icon.

Draw accurate and attractive use case diagrams with UModel® 2008 to communicate more effectively with other developers and project stakeholders. Download a free 30-day trial of Altova UModel® 2008 today!