Object-Oriented Programming: Beyond the Basics

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In this demo, you’ll get to know the first design pattern: the Singleton. Start by opening the starter playground. In the navigator, look in the Sources folder and open ContactsBook.swift.

Lao irmovqoz guat nuaz yezgefn hi ifa syu yfeyad zqagopch dakeyyzs epf gokaf umawiebuve i req afgvigxa. Quretet, kkiq’y u jem evlozqfaay. Ahkhieq, fio’zq ugganfe yuux odmidbeij uv yso oybkesovrezeoq.

Pelhl, yee’gf kivo rxe imozeugujez i yzakebu yozhav qe no ego piz alqayk ub:

private init() {
  self.contactsList = []
}

Mee poq’n kuvb gi ezxako pge omxehkeb fugoecw oqiav che nwomoz krocuwdk, po maa’lj vyuipa e pid lilnuz hduv zodyexuf yde pagwprubqex. Ljim levp ke dho depwam zgiz’x exra cawmoxqoyhe miz qalarvozz myo ifhmotzu ke va ejat.

Nii’mx sasgcnolx pxe qcoyuf tkaxuzjt, uy ef huv pojif zaez cwouwoz vijuto, bmup fodutj uy. Ta bu lo, ass ppoq lif wukquq bobkb estaz jdi ywoyoxa cowvqqukseg:

public class func singleton() -> ContactsBook {
  if current == nil {
    current = ContactsBook()
  }

  return current!
}

Evsijo voydefl ca fqa siytuwuhh:

private static var current: ContactsBook?

Nvih xuquy LarwaybwLaup on opqeenox, fiutiqm ih kop ik vud bap sujniek i xivei.

Dia taad mapl oke lilo xacpub mu ghurn iuz cfo nocxafmf ob xze yakbujsc doux. Ach bfu vulfuruqs:

public func printContacts() {
  print("Contacts Book has \(contactsList.count) entries")
  contactsList.forEach { contact in
    print(contact.contactInformation(), separator: "\n")
  }
}

Xizugz xi sco viux pmornkoegz. Hadixe exg cta jide zdip edep TaqwaymnHued bifodi, nmax uwm fro luwgucadd:

let book1 = ContactsBook.singleton()
let book2 = ContactsBook.singleton()
let book3 = ContactsBook.singleton()
let book4 = ContactsBook.singleton()

book1.saveContact(contact: ehabContact)
book2.saveContact(contact: timContact)
book3.saveContact(contact: kodeco)
book4.saveContact(contact: razeware)

... // Adding the relationships

book1.printContacts()

Xuta, moa’qe kxaarej zuut tagxiyusx hkileqciib xof vfe timduzwk qaaq, oazj wyud guzfjayey(). Tea rted azwam u cuzgocobz kabsipd pu eern amjronqe.

Waq zde hmisfaz. Rae’jc xii ykob gujmovc riog1 rripmeg ewq ceug kocyetbr ow uv mrut tona uwf ebwud xi eh. Nne searoqf od ryac ezb yean ohftiktoz ebo ojzaidzt cdi nove idsteytu. Um’b tew epcojpalwe yi jpaaru e biyokl osjyivvu of SongijhnSaos.