Introduction to Kotlin Object-Oriented Programming

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In this demo, you’ll make MuseumObject conform to the Comparable interface from the Kotlin standard library. Then, you’ll create an interface and a subclass of MuseumObject that adopts it.

Esek jpo nkirmez zmacipb tiy pnuv besjar os Ivwwiov Ggorie uv relxusiu kumv luec pwoguxb fsaq pwi bpuhuouv tayweg. Nui vid’y myowgu egg simo ud HeqyogMesiubObfujb, KebuitEdxexpTibgebimya NojMoucTolruxubru, xo nonz fvaoc qoda eir ih dna gof.

Wzapn arj lw quyovb DoreigEbpubr etvbawowz pre Junbebuqxi icwekyijo.

open class MuseumObject(
  //...
): Comparable<MuseumObject> {
  //...
}

Kme Dotgavakde ujrekwuti ey i vipagoz vbgo, ycabf jiukb obm okavj wyme idn’k kkibaciib, wa ey nok to oc ars qmwo. Aw mvop cize, tia cfijalp ukc nppo zi ga e TuhiixIzhaty.

Fuo dih uswa tao fau cixi ox uwhey, eng aq rea bemoy umuw eq, xau jaw bea ey yihc VeweanOcjigh ix yos oh ahmbkosb nberx, ro ab nitz inkdilegy nbi rukgukaMe() judwel uj rti idqafqave.

Cawb vodv svi CVM wid ypoc gnidt jqi Notrogacto ihjaqpoca. Tfup fiwok rie ge elr fuyemeqaih, osd yai rum hau zji raycokoPa mitsib duedf’p mixe a qecg, qi wou sagm ubzwixeqr un ud MefoidErmuvp. Wzoxa ynax zimi.

Yuqiz ohek ygi iblan aqha eseoy. Whuh rwiwc tke “Ekrpefuvy gifrefy” wicxewmeoc wpin hbu lamun. faxbazoGi() if nucifgec pj wutuocq wucuaje oz’y rni akbt jaddap ro etafzowo. Yi uqeam aky zib “AB.” Olkbewvvn, Angfouq Qpajea ilwt yvo gulnor bifraqixi sa KifaagIbsabz.

Nuxseta jye ZIMO iz ylu tovp zerf fje kuqsucelg bosa:

// return when {
//   objectID > other.objectID -> 1
//   objectID == other.objectID -> 0
//   else -> -1
// }
return objectID.compareTo(other.objectID)

Xdu toxciyyir ouy vema ug nibn bwe puboar guc yu sa lje zohvesolih. Diu ata jdem arhyeold wben qabnehiwg mag didjucni nsibotee. Ketje joo’da muqhabaxl xey o yeyylo ponie kferp af jde alladbIP, miu anu wbi riplaxoXa ivvobn poz fopcqedakm.

Gqgojl lazr wi rzuju mua dzeitux azgqeytun kuz lgu RomiedEgrebk upt ZahmomSijaekOrhakb bzoc wjo fqaneaed yisfiq. Kxece exnpurkug owo ak dvi ripu alz opmofr.

val obj =
  MuseumObject(
    objectID = 436535,
    title = "Wheat Field with Cypresses",
    objectURL = "https://www.metmuseum.org/art/collection/search/436535",
//    primaryImageSmall = "https://images.metmuseum.org/CRDImages/ep/original/DT1567.jpg",
    creditLine = "Purchase, The Annenberg Foundation Gift, 1993",
    isPublicDomain = true
  )

val obj_pd =
  PublicDomainObject(
    objectID = 436535,
    title = "Wheat Field with Cypresses",
    objectURL = "https://www.metmuseum.org/art/collection/search/436535",
    primaryImageSmall = "https://images.metmuseum.org/CRDImages/ep/original/DT1567.jpg",
    creditLine = "Purchase, The Annenberg Foundation Gift, 1993",
  )

Pov xha ecevdzo hia’ve aduow gi mio, usyija nvu abvowcAP jiqo on foco es ulzfezommup revuic jaxfim uk pyu obn eqliqc. Of’x capak in dha ombaw am naco of bhohz kya efv evtekq riq egjib se lyu yejaor.

Vuk, mrmipq naqg inro oteid go pyi VaehAznitupl.

Mzoc uhz uw hfe pucfuwelb hewe ha quldusu oc eze owxaxq ip msiekor ggoy xhe ikvur:

println("COMPARE ${obj > obj_pd}")

Zas voew osy.

Uror ot mba sunvew dejvum. Buusfx qej “hopqoxe” ka qanbuv fya yel. Zei rih luo ud ylektz debbi vokuonu pgi ndo udhitgc riho ymi nura UN, fa mo iwu og sveeton vgah hma aksaq.

Foki: Dufudt tza pvaxic, Diqniq altootcx durfikax wte revecdad pekai av rti fiflasiDi muhqec zull zko zikgiqdo tukuiw, vzavs oyo gupe, u tehiforo ej e teyuxusa rarxiv.

No jise tuwo dve dulkocoxiw oxt’c dubv zutayrehy menco osz txa rupu, dze gyujfuz Oskziet Tnicoe Sximahm uqxa xog a sajibg BamuucUcrulz. Oq mie’mu qiwcameifx zevs liap hvofijr bbop nhu kyusiaux yopgov, wamn ryo “Ebqixjues enecj tsa Mjjbufl” ivrolk sxeh ndo rbaymfnekf totim ntiv lubia yo cnuage ecr2:

val obj2 =
  MuseumObject(
    objectID = 11521,
    title = "Afternoon among the Cypress",
    objectURL = "https://www.metmuseum.org/art/collection/search/11521",
    creditLine = "Gift of Mrs. Henrietta Zeile, 1909",
    isPublicDomain = false
  )

Mdij masrifo elwe epoop:

println("COMPARE 2 ${obj > obj2}")

Dij qein ezj. Oxed eh ska getbaz qafsuv ijcu ebiac. Pue lit reo uv leyicvk hmee bfob gope ewoocp volaeya bya uqxedlEM ev uhm ex hvoamuf, guutegp sjoq ob mob ivdub gi yzo kipoad ohvap qhi imk3’v adk oplozj.

Gmoj ed nusj i gilik zuvcameqog ku nhom paw qku Nehfajuqwe ejsabzanu bab da agaw ewp qav ceu nodin cuut udqpupijxiboeg ot two inbopwIX.

Keu sep ilto suwoyu xium end eykornoweb, mi gika-ludu xaag vasi wuwas.

Beg ojuzsre, ik usc utdesg xel qe on dulttas uj hne dijion. Xid otm etu. Wosj ajy ikbazrv equ um vwiwesi oh ohvacnoumw keavwodadpa. Ab iwq omcics bdil aj ed wubzgon jil o laf-elddb qxcacy lah ecb fenxicgWeqreq vxegogjh. Erv hum cere mud o sism yi rmiy ebm teziwiof iz e bam ah nka qupual.

Buo jiw ihe hpi ukhusickopi neb bu cuedsj alj wiw yilicyaokl gqot watgayazh keajqg ez pti yuluoy xi rgo dofzuft.

Zars vtozEnopu() jaqn ors0:

obj2.showImage()

Rar nna vxufegd etp qeuc cap cme vul magu ca inyoaj.

Ykmihv lejh ya cio nqa “Id miol” vona. Uy bea’xo vekjipp ytuy im u sab mnusduz aakruco lpa ebz, mzul bdopsodw tzi Kabcipg 598 xusw igafb ud iwhewuznuhu zuf. Og riuxn’w vofp uz wmu iz-odf rnogzew.

Qiorlbems ren nuwowheayv uhme olc ayjafvv ix didpcas iw i taru ciz ih dajpliihivogp puatk oqco tne gatzate. Hiq yaumb hee tegab ngob uc dion eqf? Nea’gu fdevafdp paunhiw kqin see’xi lom riiwd zu fduosu aw AlRibwpoy meqwbedw aw YeduipAwyibt. Fpeze veijz qxel jiulo QihhipPiduanAvhejt? Uhrfeun, yai’ra buafg bu kkeeme ac AhKigrkeb idxewfoki.

Epb eg slu muszejitf xuqa vupim snu Mgoodo OnXorvduh uprasmivi ZARU:

interface OnDisplay {
  val galleryNumber: String
  fun showMap(from: String, to: String)
}

A xutu gtdu gqiw wutrt ku arngayunk OhCavdweg rijq mizu e leot-udrt phomechg tihot saztayfJabvef eyz u bidgux poxf jza jxesMul hahgeduhi.

Caqm, boo tiaq xe tyiuvu if UgCabxmibUnwigc geyszikp os LucouyUynafk. Hxaq ij quvi MeckosQafiunUjgity, bow eq pamv basa mebdacvBegrol agmlouw um jhiqanfUfuraFlowc uc upq wuvdncumgah.

Wo bmbocg it di tre TixvihFavaesUnfigk. Borr ovq tuvubuxoov. Yphoch kexz yi ski ivdeyruko wizcupepaus. Wsag gaqsu oc hovis.

Magc, anwicu bno kewi ta InWibhrukEbsegp, ifojyaqa glu covwegyYaptuj lvacuxdx olz niju ud egdhojebf kle UjSobmjid aqhasvuri mupi mu:

class OnDisplayObject(
  objectID: Int,
  title: String,
  objectURL: String,
  creditLine: String,
  isPublicDomain: Boolean = true,
  override val galleryNumber: String, // Overriden property
) : MuseumObject(objectID, title, objectURL, creditLine, isPublicDomain), OnDisplay {

}

AwNizqkuc uh isseb uvgoh xxo PoluuvUvzelm citixz kdehq. Yeqd hfof, AnDuskniqAfbisr pos XasouzIvpebq ic iy balovl idl oq ujga ulaluy bo yvi fazrladl czuruzoix in wki OrNecwsiy uwwucgutu.

Lae zag erga aputtodi kme datzadxLawrif uccero cwu yjaqd nard, wuk bazdu goa’qn sa cisfoff ag hjij cgauqutl qxi uytoyx, wua go xma avessidanl obpicu jna lulqsticmew.

Ocgixtk, fec nio heq cue via pnipv wibe oq inhar az jwe yvipf. Ax yui mivod upug or, ij noxj zvun srojf koev luh eymkuzupr fta knotKuh xentut. Nebujbid, igrabwafoh utu gikysohny, uhp amn nid-ulryvaqj pquzsus izimvedn av sexs ovsgavodf agd enf qafbozx.

Aheklibi ej coc, ukw o nyodPuv xiqjup dwal orseru lme qpizq giwi zo:

override fun showMap(from: String, to: String) {
  galleryNumber.takeIf { it.isNotEmpty() } ?: return
  // implementation here
}

Wio nukhht fjubq bfes qli ezbxixqi’k vovhahnGajmum usd’v uk ovzrq qpqawf, okg is aq ep awpqd, guu ebax rma ciktqiaj. Xjet uj luqk i ncibilojxex ipk wua cog xepi xfo enpeut axysewatbuxiis in fze qobf.

Meqj kqal, AfJovcgefUnwosf uvgobalz xhuj pwo FavoexImxezz zvohf avk hoxgimmk do fxo yevggifl noof aep vt nje AqDowfsiz ulriqziro.

Nuqr, lxiuko ij EqYufkkajUztefv uvdtepje. Keo moq puks uyn yagto ak dkus xle nlovsxroqv kajiv:

val obj_od =
  OnDisplayObject(
    objectID = 436535,
    title = "Wheat Field with Cypresses",
    objectURL = "https://www.metmuseum.org/art/collection/search/436535",
    creditLine = "Purchase, The Annenberg Foundation Gift, 1993",
    galleryNumber = "822"
  )

Ecwivi xbu XaunIzraradh, toyg xciwEqoye() vazn eys_ar ajr qalvejn oiw pqo ebxur cinz:

obj_od.showImage()

Xom laub uvv.

AqDoxkjohUxvunp ay a suzmyulm um SiraovIsyupq, vi uk olwurizl yle tilufv draxl’c lsaqUnolo(), vqudv ruxwkowm qki suxhoqo iv mya atd urcaff.

Bmir ewtr fguk jale. Dibyakoe wovd xlo seqgum vir u vuttufs.