Overview of use case modeling
Use cases were introduced by Jacobson in 1992. They model how the system is going to be used in a given context, giving you an overall picture of the system, from a user's point of view.
A Use Case Diagram details the possible ways in which a system can be used, that is, the Use Cases, and the interaction of objects in the system to implement those Use Cases. This type of modeling is now widely accepted as being the best means of establishing user requirements and of feeding those requirements into object-oriented analysis. In this way, the Use Case Model provides an efficient communication mechanism between users and developers.
You can create a Use Case Diagram from a Class, Data Type, Interface, Package, Signal or the Model.
On a Use Case Diagram you can create Actors and Use Cases, and the relationships between them:
• Inheritance between Actors or Use Cases.
• Interactions between Actors and Use Cases.
• Extend Flows between Use Cases.
• Include Flows between Use Cases.
Through the Relationships pane, you can see how Actors and Use Cases are related through the preceding links.