Interface use cases in Go - Mini Project: Build & Apply

Interface Use Cases in Go

📖 Scenario: You are building a simple system to handle different types of notifications in a company. Notifications can be sent via Email or SMS. Each notification type has its own way of sending messages, but your system should treat them the same way using an interface.

🎯 Goal: Create a Go program that uses an interface to send notifications through Email and SMS. You will define the interface, implement it with two types, and then use the interface to send messages.

📋 What You'll Learn

Create an interface called Notifier with a method Send(message string)

Create two structs called EmailNotifier and SMSNotifier

Implement the Send method for both EmailNotifier and SMSNotifier

Create a slice of Notifier containing both EmailNotifier and SMSNotifier

Use a for loop to call Send on each notifier with the message "Hello, team!"

Print the output of each Send call

💡 Why This Matters

🌍 Real World

Interfaces let you write flexible code that can work with different types of objects in a uniform way, like sending notifications through various channels.

💼 Career

Understanding interfaces is key for Go developers to build modular, testable, and maintainable software systems.

1

Define the Notifier interface and structs

Create an interface called Notifier with a method Send(message string). Then create two structs called EmailNotifier and SMSNotifier with no fields.

Go

// Define the Notifier interface and two structs EmailNotifier and SMSNotifier
// Your code here

Hint

Interfaces in Go are defined using the type keyword followed by the interface name and the methods inside curly braces.

2

Implement the Send method for both structs

Write the Send(message string) method for EmailNotifier that prints "Sending Email: " followed by the message. Also write the Send(message string) method for SMSNotifier that prints "Sending SMS: " followed by the message.

Go

package main

type Notifier interface {
	Send(message string)
}

type EmailNotifier struct {}
type SMSNotifier struct {}

// Implement Send for EmailNotifier
// Implement Send for SMSNotifier
// Your code here

Hint

Methods are defined with a receiver in parentheses before the method name. Use println to print the message.

3

Create a slice of Notifier and add instances

Create a variable called notifiers which is a slice of Notifier. Add one EmailNotifier and one SMSNotifier to this slice.

Go

package main

type Notifier interface {
	Send(message string)
}

type EmailNotifier struct {}
type SMSNotifier struct {}

func (e EmailNotifier) Send(message string) {
	println("Sending Email: " + message)
}

func (s SMSNotifier) Send(message string) {
	println("Sending SMS: " + message)
}

// Create a slice of Notifier called notifiers
// Add EmailNotifier and SMSNotifier instances
// Your code here

Hint

Use a slice literal to create the slice with both struct instances inside curly braces.

4

Use a loop to send the message and print output

Add a main function if not present. Use a for loop with variable _, notifier to iterate over notifiers. Call notifier.Send("Hello, team!") inside the loop to send the message. This will print the output.

Go

package main

type Notifier interface {
	Send(message string)
}

type EmailNotifier struct {}
type SMSNotifier struct {}

func (e EmailNotifier) Send(message string) {
	println("Sending Email: " + message)
}

func (s SMSNotifier) Send(message string) {
	println("Sending SMS: " + message)
}

func main() {
	notifiers := []Notifier{EmailNotifier{}, SMSNotifier{}}

	// Use a for loop to call Send on each notifier with message "Hello, team!"
	// Your code here
}

Hint

The for loop iterates over the slice and calls the Send method on each notifier, printing the message.