Use Case Diagram for WhatsApp

Description:

A use case diagram visually represents the interactions between users (actors) and the system (WhatsApp). It identifies the major use cases (functionalities) of the system and shows how the primary and secondary actors are involved in each.

Actors:

• User – The person who uses WhatsApp to communicate.
• Group Admin – A user with special permissions in group chats.
• WhatsApp Server – The backend system that manages message flow, authentication, and storage.
• Push Notification System – Handles notification delivery.
• Media Storage Service – Stores images, videos, and documents.

Use Cases (Functionalities):

1. Register/Login

• Actor: User
• Description: The user registers via mobile number and logs in through verification (OTP-based).

2. Send/Receive Message

• Actor: User, WhatsApp Server
• Description: The core feature of sending and receiving text messages.

3. Voice/Video Call

• Actor: User
• Description: Users can initiate or receive voice and video calls.

4. Create/Manage Group

• Actor: Group Admin
• Description: Admin creates groups, adds/removes members, and manages group settings.

5. Send Media Files

• Actor: User, Media Storage
• Description: Allows sending images, videos, and documents through chat.

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6. Update Status

• Actor: User
• Description: Users can update text, image, or video-based status visible for 24 hours.

7. View Contacts

• Actor: User
• Description: User can access and sync device contacts who use WhatsApp.

8. Receive Notifications

• Actor: Push Notification System
• Description: Delivers real-time message/call alerts when the app is inactive.

9. End-to-End Encryption

• Actor: WhatsApp Server
• Description: Ensures security during message transmission between users.

Visual Representation (Structure):

In the diagram (which you can draw on board or slide):

• Place User and Group Admin outside the system boundary (on the left).
• Place System (WhatsApp) inside the rectangle.
• Each use case is shown as an oval inside the system boundary.
• Connect the actors to the use cases with lines to indicate interaction.

Explanation Tips for Class:

• Use this diagram to emphasize separation between front-end (user interactions) and back-end (server and systems).
• Highlight how each use case represents a discrete, user-centered functionality.
• Reinforce the importance of roles like Admin vs. regular User.
• Use arrows to show interactions and dependencies.