Design for change and extensibility in Software Engineering - Mini Project: Build & Apply

Design for Change and Extensibility

📖 Scenario: You are working on a simple software system that manages notifications for users. The system currently supports only email notifications, but you want to prepare it so that it can easily add other notification types like SMS or push notifications in the future.

🎯 Goal: Build a basic design structure that supports easy addition of new notification types without changing existing code. You will create a simple setup, add a configuration variable, implement the core logic to send notifications, and complete the design to allow future extensibility.

📋 What You'll Learn

Create a dictionary called notifications with one entry: 'email': 'Send email notification'

Add a variable called default_notification set to 'email'

Write a function called send_notification that takes a method parameter and returns the message from notifications for that method

Add a new notification type 'sms' with the message 'Send SMS notification' to the notifications dictionary

💡 Why This Matters

🌍 Real World

Designing software that can easily adapt to new requirements, like adding new notification channels without rewriting existing code.

💼 Career

Software engineers often need to write code that is easy to maintain and extend. This project teaches a basic approach to achieve that.

1

DATA SETUP: Create the initial notifications dictionary

Create a dictionary called notifications with one entry: 'email': 'Send email notification'

Software Engineering

# Create the notifications dictionary with email notification
# Your code here

Hint

Use curly braces {} to create a dictionary with the key 'email' and its message.

2

CONFIGURATION: Add the default notification method

Add a variable called default_notification and set it to the string 'email'

Software Engineering

notifications = {'email': 'Send email notification'}
# Add the default_notification variable
# Your code here

Hint

Just assign the string 'email' to the variable default_notification.

3

CORE LOGIC: Write the send_notification function

Write a function called send_notification that takes a parameter method and returns the message from the notifications dictionary for that method

Software Engineering

notifications = {'email': 'Send email notification'}
default_notification = 'email'

# Define send_notification function
# Your code here

Hint

Use the dictionary get method to safely get the message for the given method.

4

COMPLETION: Add SMS notification to the dictionary

Add a new entry to the notifications dictionary with key 'sms' and value 'Send SMS notification'

Software Engineering

notifications = {'email': 'Send email notification'}
default_notification = 'email'

def send_notification(method):
    return notifications.get(method, 'Notification method not supported')

# Add SMS notification to notifications dictionary
# Your code here

Hint

Add the new key-value pair inside the notifications dictionary.