Drawing use case diagrams

Use case diagram lets you model system functions (i.e. goals) as well as the actors that interact with those functions. You can draw use case diagrams in VP-UML as well as to document the event flows of use cases using the flow-of-events editor. In this page, you will see how to draw use case diagram. Flow of events will be mentioned in coming pages.

Creating a use case diagram

To create a use case diagram, take any of the steps below:

• Click on UML on toolbar and select Use Case Diagram from the drop down menu.
  
• Right click on Use Case Diagram in Diagram Navigator and select New Use Case Diagram from the popup menu.
• Select File > New Diagram > UML Diagrams > Use Case Diagram from the main menu.

Create a use case diagram

 

Enter name for the newly created use case diagram in the text field of pop-up box on the top left corner.

Enter name for the newly created use case diagram

Drawing a system

To create a system, select System on the diagram toolbar and then click it on the diagram pane. Finally, name the newly created system when it is created.

Create a system

Drawing an actor

To draw an actor, select Actor on the diagram toolbar and then click it on the diagram pane. Finally, name the newly created actor when it is created.

Create an actor

Drawing a use case

Besides creating a use case through diagram toolbar, you can also create it through resource icon.

Move the mouse over a shape and press a resource icon that can create use case. Drag it and then release the mouse button until it reaches to your preferred place. The source shape and the newly created use case are connected. Finally, name the newly created use case.

Create a use case through resource icon

Line wrapping use case name

If a use case is too wide, for a better outlook, you may resize it by dragging the filled selectors. As a result, the name of use case will be line-wrapped automatically.

Resize a use case

Drawing <<Extend>> relationship

To create an extend relationship, move the mouse over a use case and press its resource icon Extend -> Use Case. Drag it to your preferred place and then release the mouse button. The use case with extension points and a newly created use case are connected. After you name the newly created use case, a pop-up dialog box will ask whether you want the extension point to follow the name of use case. Click Yes if you want it to do so; click NO if you want to enter another name for extension point.

Create an extend relationship

Drawing <<Include>> relationship

To create an include relationship, mouse over a use case and press its resource icon Include -> Use Case. Drag it to your preferred place and then release the mouse button. A new use case together with an include relationship is created. Finally, name the newly created use case.

Include relationship is created

Structuring use cases with package

You can organize use cases with package when there are many of them on the diagram.

Select Package on the diagram toolbar (under Common category).

Create a package

Drag the mouse to create a package surrounding those use cases.

Surround use cases with package

Finally, name the package.

Name the package

Drawing business use case

1. Right click on a use case and select Model Element Properties > Business Model from the pop-up menu.
   

   Click Business Model

2. After selected, an extra slash will be shown on the left edge of the use case.
   

   Business model