Unlocking the Power of Swift: A Shift Towards Protocol-Oriented Programming

The Limitations of Inheritance

In traditional object-oriented programming with languages like Objective-C, creating new objects can be a slow and cumbersome process, often resulting in unnecessary functionalities. Complex class hierarchies can lead to inefficiencies and race conditions, making maintenance a nightmare.

Introducing Protocols in Swift

A protocol is a blueprint that defines methods and values, serving as a communication contract between unrelated objects. It allows developers to group methods, properties, and functions, making it easier to model complex systems. Protocols can conform to classes, enums, and structs, and multiple protocols can be applied to a single object.

A Real-World Example: Building a Salary Remittance System

Let’s say we’re building an application that requires a salary remittance system. We can define a protocol to model the requirements, and then create a class that conforms to this protocol. This approach allows us to decouple our objects from each other, making it easier to maintain and extend our system.

protocol SalaryRemittance {
    var employeeID: Int { get set }
    var salary: Double { get set }
    func calculateRemittance() -> Double
}

class Employee: SalaryRemittance {
    var employeeID: Int
    var salary: Double

    init(employeeID: Int, salary: Double) {
        self.employeeID = employeeID
        self.salary = salary
    }

    func calculateRemittance() -> Double {
        // implement remittance calculation logic
        return 0.0
    }
}

The Advantages of Protocols

So, why are protocols so useful in Swift? The advantages are clear:

• Code Clarity: Naming protocols provides a better understanding of their instances, making our code more readable and maintainable.
• Reusability: With protocol extensions, we can provide default implementations for our methods, reducing code duplication and making our lives easier.
• Separation of Classes: Protocols eliminate the need for classes, enums, and structs to be dependent on each other, making our system more modular and flexible.

A Mobile Example: Generating an IMEI Code

Let’s take a look at a more common use case for protocols in mobile development. We can define a protocol to generate an IMEI code, and then create a struct that conforms to this protocol. The mutating keyword ensures that our object can change its properties as needed.

protocol IMEIGenerator {
    var imeiCode: String { get set }
    mutating func generateIMEI()
}

struct MobileDevice: IMEIGenerator {
    var imeiCode: String

    init(imeiCode: String = "") {
        self.imeiCode = imeiCode
    }

    mutating func generateIMEI() {
        // implement IMEI code generation logic
        imeiCode = "012345678901234"
    }
}