Swift Factory Design Pattern with Dependency Inversion Principle

FactoryDesignPatternExample.swift

// Define protocols for Service and Repository

protocol Service {
    func fetchData() -> String
}

protocol Repository {
    func saveData(data: String)
}

// Concrete implementations of Service and Repository

class ConcreteService: Service {
    func fetchData() -> String {
        return "Data from Service"
    }
}

class ConcreteRepository: Repository {
    func saveData(data: String) {
        print("Saving data: \(data)")
    }
}

// ViewModel with dependencies

class ViewModel {
    private let service: Service
    private let repository: Repository

    init(service: Service, repository: Repository) {
        self.service = service
        self.repository = repository
    }

    func processData() {
        let data = service.fetchData()
        repository.saveData(data: data)
    }
}

// Factory for creating ViewModel instances

class ViewModelFactory {
    static func createViewModel() -> ViewModel {
        let service = ConcreteService()
        let repository = ConcreteRepository()
        return ViewModel(service: service, repository: repository)
    }
}

// Usage

let viewModel = ViewModelFactory.createViewModel()
viewModel.processData()