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Milav Dabgar
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Milav Dabgar
Experienced lecturer in the electrical and electronic manufacturing industry. Skilled in Embedded Systems, Image Processing, Data Science, MATLAB, Python, STM32. Strong education professional with a Master’s degree in Communication Systems Engineering from L.D. College of Engineering - Ahmedabad.
Lecture 21: UML Use Case Diagrams

Lecture 21: UML Use Case Diagrams

Unit 3: Requirement Analysis and Design (4353202)

Lecture Agenda

  • Recap of UML Introduction
  • What is a Use Case Diagram?
  • Components of a Use Case Diagram
  • Relationships in Use Case Diagrams
  • Example: Library Management System Use Case Diagram
  • Advantages of Use Case Diagrams
  • Key Takeaways

Recap of UML Introduction

UML (Unified Modeling Language) is a standardized visual language for modeling software systems. It includes structural and behavioral diagrams to visualize, specify, construct, and document system artifacts.

What is a Use Case Diagram?

A Use Case Diagram is a behavioral UML diagram that describes the functionality of a system from the user's perspective. It shows how different users (actors) interact with the system to achieve specific goals (use cases).

It defines the boundaries of the system and its primary functions.

Components of a Use Case Diagram

  • Actor: Represents a user or any entity that interacts with the system. (Stick figure)
  • Use Case: Represents a specific function or goal that an actor can achieve with the system. (Oval)
  • System Boundary: A rectangle that defines the scope of the system, separating what is inside the system from what is outside.
  • Association: A line connecting an actor to a use case, indicating that the actor participates in that use case.

Relationships in Use Case Diagrams

  • Include: A relationship where one use case (the base) incorporates the functionality of another use case (the inclusion). The included use case is mandatory for the base use case.
  • Extend: A relationship where one use case (the extension) adds optional functionality to another use case (the base). The extension use case is executed only under certain conditions.
  • Generalization: A relationship between a more general use case and a more specific use case, where the specific use case inherits the behavior of the general use case. (Similar to inheritance in classes).

Example: Library Management System Use Case Diagram

graph TD Actor1[Librarian] --> (Issue Book) Actor1 --> (Return Book) Actor1 --> (Add Book) Actor2[Student] --> (Issue Book) Actor2 --> (Return Book) Actor2 --> (Search Book) subgraph Library Management System (Issue Book) (Return Book) (Add Book) (Search Book) end

Advantages of Use Case Diagrams

  • User-Centric: Focuses on what the user needs the system to do.
  • Communication: Easy for both technical and non-technical stakeholders to understand.
  • High-Level View: Provides a clear overview of system functionality.
  • Basis for Testing: Can be used to derive test cases for system validation.
  • Scope Definition: Helps in defining the boundaries and scope of the system.

Key Takeaways

  • **Use Case Diagrams** describe system functionality from the **user's perspective**.
  • They consist of **actors, use cases, and system boundaries**.
  • Key relationships are **include, extend, and generalization**.
  • They are excellent for **communication** and **defining system scope**.

Next Lecture

Topic: UML Class Diagrams

Q & A

Questions & Discussion