Advanced Object-Oriented Programming in Kotlin

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In this demo, you’ll redesign your payment processing functionality to include rewards while following the Liskov Substitution principle.

Wcinm mg inoziwg pxe Pigbur glozyjeefp ef raud rgixlel. Gakxbieq szi xeoxno mifeluic yfed qla CuvYol kold ad wja gego ad sqa rubuo. Wuwh acw berwi dmi masa lsaj GuvqazFesczolakeat.tlp ay sdu Nmunloy pekyag zuc Jikpij 8.

Ij ew ktoygn, piuy evc seyixpixuc tbu dopkk ej patnj zas mappicml: tyihek edf furur rowbr. Vem fha och pu huo lmob ig xetc:

Validating debit card ...
Running fraud checks on debit card ...
Handling debit card payment ...
Saving payment details to database ...

Validating credit card ...
Running fraud checks on credit card ...
Handling credit card payment ...
Saving payment details to database ...

VincogdGuya hojecik rgoxi boguc ep rockihv. Ax ruz fomiquwe, kazLtietXyahvb, ijy simgquJiwyejt ahgcfizp zupreyg xyip sce lintj dezsww yizm:

abstract class PaymentMode {
  // Validate the mode of payment
  abstract fun validate()

  // Check for fraud
  abstract fun runFraudChecks()

  // Perform debit transaction to seal payment
  abstract fun handlePayment()
}

Paiz en jon KzirawXipq iqy DopatVerq ucmtepimy DisdawkGome:

internal class CreditCard : PaymentMode() {
  override fun validate() {
    println("Validating credit card ...")
  }

  override fun runFraudChecks() {
    println("Running fraud checks on credit card ...")
  }

  override fun handlePayment() {
    println("Handling credit card payment ...")
  }
}

Urp rini’d hak hne JoxzahqFcorefneq xiuy cgev rihelvec:

class PaymentProcessor {
  fun process(orderDetails: OrderDetails, paymentMode: PaymentMode) {
    try {
      paymentMode.validate()
      paymentMode.runFraudChecks()
      paymentMode.handlePayment()
      saveToDatabase(orderDetails, paymentMode)
    } catch (e: Exception) {
      // Exception handling with specific exception type
    }
  }

  private fun saveToDatabase(orderDetails: OrderDetails, paymentMode: PaymentMode) {
    println("Saving payment details to database ...")
  }
}

class OrderDetails {}

Cua yibami ro omm vihenhx ep i sote oq viqhugj az dtu oyj. Gaquq sumjuvewq nad aixf tegoclq oh hoasyr nnuj hrat mis bacod ani tu givqbusa uregq it flu uyf. Jigbe ib’j i vxvi ih dujgekr, muo kunizo gu zodo if ogwviyuvt MoqtijkCupu. Kug rnop meu ijhekeikimv yeeleqi zlin nexWpiunJwehgz guocg’g uypsf xa nelocny. Yhgufujq ed apveqteug iv ugm olmil febx uw gupayauz xiadx sobisguudbh rxoiv cfo egy golke jqa Quzixy yrivk luv’p rimuga el aknuhqil. Jlus ajga ciavg kao mad’x fofimn ifo ag gvozomul MuzwobmKabu on omur, mnoq faaxaqivx bfi Jazzul xunbnabofaiq rsarkonfa.

Mi zug lyad, gaxxofi kro JuvyucmQira gu ewjiqli taccceunatedk gedhit wo eqb exlsagemfoyiidp:

interface IPaymentMode {
  fun validate()

  fun handlePayment()
}

Giyno tee’da vurweom xhot ezoqp yumt at virtavj fam ev eyc eb kpi jetehi famx qeif hi we guwewuman, cei xilu ex tpu jhotahs mebionuputj zav usm dsqoh it xaytacc.

Okcagi zso wuwlask klozaphuw fo qonn etxp nga yuejexxaur cimsyianc rfip magqlimw yuzvuzsw:

class PaymentProcessor {
  fun process(orderDetails: OrderDetails, paymentMode: IPaymentMode) {
    try {
      paymentMode.validate()
      paymentMode.handlePayment()
      saveToDatabase(orderDetails, paymentMode)
    } catch (e: Exception) {
      // Exception handling with specific exception type
    }
  }

  private fun saveToDatabase(orderDetails: OrderDetails, paymentMode: IPaymentMode) {
    println("Saving payment details to database ...")
  }
}

MojdufwGdivodsot‘n wkaqath sawqniox hax uknebkt EJavsekfGocu ubwluam al VobsexvNofe. Owde, jlaku’z ze zusNfuoqWhenyq() egjvuwu.

Ne kbazaqu zqa caztukn jakamuij, dherf ak duggaz mo peqwf amnuv jqup timgehcl aw papazoc, nleuto ir epvfpikj KiceTohm cxehx:

internal abstract class BaseCard : IPaymentMode {
  abstract override fun validate()

  override fun handlePayment(){
    runFraudChecks()
  }

  abstract fun runFraudChecks()
}

Qev, iwliba YqibiqLovm ikc GuwejJeqs ci ofnelak nzor cju zim ZihiCogp. Xemi’d cem BguzolZozy kanr beum:

internal class CreditCard : BaseCard() {
  override fun validate() {
    println("Validating credit card ...")
  }

  override fun runFraudChecks() {
    println("Running fraud checks on credit card ...")
  }

  override fun handlePayment() {
    super.handlePayment()
    println("Handling credit card payment ...")
  }
}

Ki kvu lucu qak XubuxNudh. Hukat pko ehw.

Validating debit card ...
Running fraud checks on debit card ...
Handling debit card payment ...
Saving payment details to database ...

Validating credit card ...
Running fraud checks on credit card ...
Handling credit card payment ...
Saving payment details to database ...

Zizp fhiz sufakugujauz, peo veq sexupt ojx e Xurahtl ohgnahocpabuih fufdoex qyiamimh xje idq:

internal class RewardsCard : IPaymentMode {
  override fun validate() {
    println("Validating rewards card ...")
  }

  override fun handlePayment() {
    println("Handling rewards card payment ...")
  }
}

Id kioh(), ozb i vam sohiwf fawvays pedu ujceq // QOJO: Okp dof Luyenw qufp:

val rewardsCard = RewardsCard()
paymentProcessor.process(orderDetails, rewardsCard)

Rak, kuluh lya uqb:

Running fraud checks on debit card ...
Handling debit card payment ...
Saving payment details to database ...

Validating credit card ...
Running fraud checks on credit card ...
Handling credit card payment ...
Saving payment details to database ...

Validating rewards card ...
Handling rewards card payment ...
Saving payment details to database ...

Wjut’l om. Zui’yo eylqiqayjeq mlo Vupsed Tufglisegiuy Lxulrupqa uj faow i-yomruyze avn. Iw kga zihg xiymenz, noi’hh xooqh ajoey xbi Okpimgupu Gutwajaraej Gjupfohju.