Exercise 20-part1

Exercise 20: Modeling with UML

Use Case, Class, Sequence, Collaboration, State chart, Activity, COmponent and Deployment diagrams are used in UML. Describe each of the eight(8) main diagrams used in UML.

A. Use Case Diagram

I learn the Use Case diagram from the tuturial web site, Developer(2009).

A1. Objectiive of Use Case Diagram in UML

A use case diagram is quite simple in nature and depicts two types of elements: one representing the business roles and the other representing the business processes.

A2. The elements of a Use Case Diagram.

• Actors - it portrays any entity (or entities) that performs certain roles in a given system. The different roles the actor represents are the actual business roles of users in a given system. An actor in a use case diagram interacts with a use case. See below figure.

• Use Case - A use case in a use case diagram is a visual representation of a distinct business functionality in a system. The key term here is "distinct business functionality."See figure.

• System boundary - A system boundary defines the scope of what a system will be. functionality."See below figure.

• Relationships in Use Cases - Use cases share different kinds of relationships. A relationship between two use cases is basically a dependency between the two use cases, for example, when a use case is depicted as using the functionality of another use case in a diagram, this relationship between the use cases is named as an include relationship(See figure 4) ; A relationship between two use cases, the child use case adds to the existing functionality and characteristics of the parent use case, it is named as an extend relationship; A relationship involves a parent-child relationship between use cases. The child use case in the generalization relationship has the underlying business process meaning, but is an enhancement of the parent use case, it is named as generalization relationship.

Include relationship.


Extend Relationship


Generalization relationship.

Refereance:

Developer (2009). "Creating Use Case Diagrams". Received 5th May, 2009 from URL - http://www.developer.com/design/article.php/10925_2109801_1