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Use Case Diagram

Oct 30, 20242 min read

Use Case Diagram

A Use Case Diagram is a visual representation of the interactions between actors and a system. It is used to show the functionalities of a system from a user’s perspective, highlighting what the system does rather than how it does it.

Use Case Diagram Examples

Key Components

UML is the default tool for graphical representation. Specification Overview

Example Diagram invert_B

  1. Actors:

    • Represent entities (people, other systems) that interact with the system.
    • Symbol: Stick figure.

  2. Use Cases:

    • Describe the actions or functions that the system provides.
    • Symbol: Oval/ellipse with the name of the use case inside.

  3. System Boundary:

    • Represents the scope of the system.
    • Symbol: A rectangle enclosing all the use cases.

  4. Relationships:

    • Associations:
      • Represent interactions between actors and use cases.
      • Symbol: A solid line connecting actors to use cases.
    • Include:
      • Indicates that a use case includes the behavior of another use case.
      • Symbol: Dotted arrow pointing toward the included use case.
    • Extend:
      • Indicates that a use case may be extended by another use case under certain conditions.
      • Symbol: Dotted arrow pointing toward the extending use case.
    • Generalization:
      • Represents an inheritance relationship between actors or use cases.
      • Symbol: Solid line with a hollow arrowhead pointing toward the general actor or use case.

Heuristic Rules for Better Use Case Diagram Usability

(Hadi Putra & Hasibuan, 2018)

  1. Arrange Use Cases by Expected Normal Sequence of Flow of Events

    • The sequence of use cases should follow a logical flow from top-left to bottom-left within the system boundary.

  2. Manage Use Case Diagram Complexity by Calibrating the Level of Abstraction

    • Closely related use cases should be grouped to enhance overall readability and comprehension.
    • For complex diagrams, the use case diagram should have no more than 10 use cases, all with proper levels of abstraction.

  3. Use Actor Generalization to Indicate Level of Access

    • Actor generalization helps identify access levels or roles, often a reflection of non-functional requirements.

  4. Maintain Identical Dimensions for Use Case Ellipses and Appropriate White Spaces

    • Ensure consistent dimensions for use case ellipses and maintain adequate white space between them for visual clarity.

Graph View

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