Swift adapter design sample – The.Swift.Dev.

Fist of all let me emphasize that, that is the actual world illustration of what we’ll construct on this little Swift adapter sample tutorial:

Adapter is a structural design sample that enables objects with incompatible interfaces to work collectively. In different phrases, it transforms the interface of an object to adapt it to a distinct object.

So adapter can remodel one factor into one other, typically it is known as wrapper, as a result of it wraps the item and offers a brand new interface round it. It is like a software program dongle for particular interfaces or legacy courses. (Dongle haters: it is time to go away the previous behind!) 😂

Adapter design sample implementation

Creating an adapter in Swift is definitely an excellent simple job to do. You simply must make a brand new object, “field” the outdated one into it and implement the required interface in your new class or struct. In different phrases, a wrapper object will probably be our adapter to implement the goal interface by wrapping an different adaptee object. So once more:

Adaptee

The article we’re adapting to a particular goal (eg. old-school USB-A port).

Adapter

An object that wraps the unique one and produces the brand new necessities specified by some goal interface (this does the precise work, aka. the little dongle above).

Goal

It’s the object we wish to use adaptee with (our USB-C socket).

The right way to use the adapter sample in Swift?

You need to use an adapter if you wish to combine a third-party library in your code, however it’s interface does not match along with your necessities. For instance you’ll be able to create a wrapper round a whole SDK or backend API endpoints as a way to create a standard denominator. 👽

In my instance, I’ll wrap an EKEvent object with an adapter class to implement a model new protocol. 📆

import Basis
import EventKit


protocol Occasion {
    var title: String { get }
    var startDate: String { get }
    var endDate: String { get }
}


class EventAdapter {

    personal lazy var dateFormatter: DateFormatter = {
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "yyyy. MM. dd. HH:mm"
        return dateFormatter
    }()

    personal var occasion: EKEvent

    init(occasion: EKEvent) {
        self.occasion = occasion
    }
}


extension EventAdapter: Occasion {

    var title: String {
        return self.occasion.title
    }
    var startDate: String {
        return self.dateFormatter.string(from: occasion.startDate)
    }
    var endDate: String {
        return self.dateFormatter.string(from: occasion.endDate)
    }
}


let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "MM/dd/yyyy HH:mm"

let calendarEvent = EKEvent(eventStore: EKEventStore())
calendarEvent.title = "Adapter tutorial deadline"
calendarEvent.startDate = dateFormatter.date(from: "07/30/2018 10:00")
calendarEvent.endDate = dateFormatter.date(from: "07/30/2018 11:00")


let adapter = EventAdapter(occasion: calendarEvent)

One other use case is when it’s important to use a number of present last courses or structs however they lack some performance and also you wish to construct a brand new goal interface on high of them. Generally it is a sensible choice to implement an wrapper to deal with this messy state of affairs. 🤷‍♂️

That is all in regards to the adapter design sample. Normally it is very easy to implement it in Swift – or in some other programming language – however it’s tremendous helpful and typically unavoidable. Children, keep in mind: do not go too onerous on dongles! 😉 #himym