UML Diagram: Use Case
(Free Web Tutorials)
by Michael Thomas
UML Home Page
On the UML Home page, you can download
the whole UML site (all content, tutorials & examples) !!!
(Note: All of the EclipseUML projects
used in these tutorials are in .zip files located at:
uml\eclipse\viewonly . Just extract them into your workspace.)
- Review the UML Overview tutorial.
- Get a broad over view of a UML "Use Case" diagram.
Definition & Example
- Use Case Diagram - diagram of the use cases (software
functions/services) and the role of the actors (users - both humans or
systems). This diagram is from the user's perspective.
Example - (created with EclipseUML
- May of 2008) - Use Case Diagram for a high level view of a Hotel
- Example - (created with Rational Software Modeler v6.0 - Sept of 2005) -
Use Case of an online order system.
Goals of the Use Case diagram
- Show the roles of the actors (humans, services, etc...) as they interact
with the system (Use Cases) and the desired behavior.
- Show the intended behavior of the system without trying to implemented
- Create a diagram that domain experts, end users and developers can
- Create Use Case diagrams for key system desired behaviors (functional
requirements) from a user's perspective.
- Create a "Use Case" diagram to show how actors get the system to perform
a task for them.
- A "Use Case" diagram is a collection of actors and their roles in
communicating with the use case.
UML Use Case Diagram Terms (used by EclipseUML for UML2)
- Actor - human, system or service which interacts with a use case
- Role - the role the actor has with the use case.
- Generalization - describes a parent / child relationship where the child
is more specialized in it's task.
- Include - (make a call) - a use case invokes another use case.
- Extend - (conditional call) - a use case that may or may not invoke
another use case.
- Association - use a solid line to indicate that an actor is associated
or involved with a use case. It does NOT represent flow of information.
- Aggregation - three types: None, Shared, Composition
- Multiplicity - describes the number of elements in a set.
- 0..1 - zero to one
- 1 - one to one
- * - many to many
- 1..* - one to many
- Stereotype - is a way to extend an element from an existing one that is
specific to your situation.
- Router (under construction)
- Diagram Link - a link to another diagram.