Fist of all let me emphasize that, that is the actual world illustration of what we will 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 rework 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 lessons. (Dongle haters: it is time to depart the previous behind!) 😂

Adapter design sample implementation

Creating an adapter in Swift is definitely a brilliant straightforward process to do. You simply have to make a brand new object, “field” the previous 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 item we’re adapting to a particular goal (e.g. 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 need to use adaptee with (our USB-C socket).

Learn how 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, nevertheless it’s interface does not match together with your necessities. For instance you may create a wrapper round a complete SDK or backend API endpoints with a view to create a standard denominator. 👽

In my instance, I will 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 {

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

    non-public 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 a must to use a number of current ultimate lessons or structs however they lack some performance and also you need to construct a brand new goal interface on prime of them. Typically it is a sensible choice to implement an wrapper to deal with this messy state of affairs. 🤷‍♂️

That is all concerning the adapter design sample. Often it is very easy to implement it in Swift – or in some other programming language – nevertheless it’s tremendous helpful and typically unavoidable.

Youngsters, keep in mind: do not go too laborious on dongles! 😉 #himym