Use Case Diagrams

I l @ ve RuBoard

A use case diagram is a graphical view of some or all of the actors, use cases, and their interactions identified for a system. Each system typically has a Main Use Case diagram, which is a picture of the system boundary (actors) and the major functionality provided by the system (use cases). Other use case diagrams may be created as needed. Some examples follow:

• A diagram showing all the use cases for a selected actor

• A diagram showing all the use cases being implemented in an iteration

• A diagram showing a use case and all its relationships

CREATING THE MAIN USE CASE DIAGRAM IN RATIONAL ROSE

1. Double-click on the Main diagram in the Use Case View in the browser to open the diagram.

2. Click to select an actor in the browser and drag the actor onto the diagram.

3. Repeat step 2 for each additional actor needed in the diagram.

4. Click to select a use case in the browser and drag the use case onto the diagram.

5. Repeat step 4 for each additional use case needed in the diagram.

Note

Actors and use cases may also be created directly on a use case diagram by using the toolbar.

CREATING COMMUNICATE ASSOCIATIONS IN RATIONAL ROSE

1. Click to select the Association icon or the Unidirectional Association icon from the diagram toolbar. Note: If the Association icon is not present on the toolbar, it may be added by right-clicking on the toolbar, selecting the Customize menu choice from the shortcut menu, and adding the icon to the toolbar.

2. Click on an actor initiating a communication and drag the association line to the desired use case.

To add the communicate stereotype (optional):

1. Double-click on the association line to make the Specification visible.

2. Click the arrow in the Stereotype field to make the drop-down menu visible, and select communicate.

3. Click the OK button to close the Specification.

4. Repeat the preceding steps for each additional communicate relationship.

CREATING INCLUDE RELATIONSHIPS IN RATIONAL ROSE

1. Click to select the Dependency icon from the toolbar.

2. Click on the base use case and drag the Dependency icon to the used use case.

3. Double-click on the dependency arrow to make the Specification visible.

4. Click the arrow in the Stereotype field to make the drop-down menu visible, and select include.

5. Click the OK button to close the Specification.

CREATING EXTEND RELATIONSHIPS IN RATIONAL ROSE

1. Click to select the Dependency icon from the toolbar.

2. Click on the use case containing the extended functionality and drag the Dependency icon to the base use case.

3. Double-click on the dependency arrow to make the Specification visible.

4. Click the arrow in the Stereotype field to make the drop-down menu visible and select extend.

5. Click the OK button to close the Specification.

The Main use case diagram for the ESU Course Registration System is shown in Figure 3-10.

CREATING ADDITIONAL USE CASE DIAGRAMS IN RATIONAL ROSE

1. Right-click on the Use Case View in the browser to make the shortcut menu visible.

2. Select the New:Use Case Diagram menu option.

3. While the use case diagram is selected, enter the name of the actor.

4. Open the diagram and add actors, use cases, and interactions to the diagram as needed.

Figure 3-10. Main Use Case Diagram

An additional use case diagram is shown in Figure 3-11.

Figure 3-11. An Additional Use Case Diagram

I l @ ve RuBoard