Either で想定内のエラーと想定外のエラーを別ものにしたい！

Rx Ja Night Vol.2 (https://connpass.com/event/57150/)

Transcript

1. &JUIFSד

   䟝㹀ⰻךؒٓ٦ה

   䟝㹀㢩ךؒٓ٦׾

   ⴽ׮ךח׃׋ְ
   3Y+B/JHIU7PM
   

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2. 㹧♴畆㣐龤
   $IBU8PSL吳䒭⠓爡
   ،فٔ؛٦ءّٝꟚ涪鿇ث٦ئ٦ت٦
   !SZVHPP@
   

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3. ⹛堣
   䟝㹀ⰻך㣟侁䟝㹀㢩ך㣟侁׾ⴓֽ׋ְ
   䟝㹀ⰻ
   8FC"1*ؙٔؒأزָة؎ي،ؐز׃׋
   䟝㹀㢩
   ءأذيך㉏겗זו
   

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4. 3Y+BWBךؒٓ٦عٝسؚٔٝ
   0CTFSWBCMFPO&SSPS
   'MPXBCMFPO&SSPS
   4JOHMFPO&SSPS
   $PNQMFUBCMFPO&SSPS
   .BZCFPO&SSPS
   ؒٓ٦ך「ֽ《׶⯓כא
   

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5. ⢽
   ؙٔحؙ̔ؿ؋؎ٕ《䖤̔،حفٗ٦س
   RxBinding.clicks(button)
   .map { /* Get file */ }
   .flatMap { /* Upload */ }
   ~~~~~
   .subscribe({
   /* Success */
   }, {
   /* IOException or Request failure */
   })
   

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6. RxBinding.clicks(button)
   .map { /* Get file */ }
   .flatMap { /* Upload */ }
   ~~~~~
   .subscribe({
   /* Success */
   }, {
   /* IOException or Request failure */
   })
   ֿֿדPO&SSPSָ鸐濼ׁ׸׷ה
   ⢽
   ؙٔحؙ̔ؿ؋؎ٕ《䖤̔،حفٗ٦س
   

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7. RxBinding.clicks(button)
   .map { /* Get file */ }
   .flatMap { /* Upload */ }
   ~~~~~
   .subscribe({
   /* Success */
   }, {
   /* IOException or Request failure */
   })
   4VCTDSJCFSPO&SSPSחⳢ椚ָ獳׶
   ⢽
   ؙٔحؙ̔ؿ؋؎ٕ《䖤̔،حفٗ٦س
   

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8. RxBinding.clicks(button)
   .map { /* Get file */ }
   .flatMap { /* Upload */ }
   ~~~~~
   .subscribe({
   /* Success */
   }, {
   /* IOException or Request failure */
   })
   ؙٔحؙ؎كٝزכ׮ֲ굲׿דֿזְ
   ⢽
   ؙٔحؙ̔ؿ؋؎ٕ《䖤̔،حفٗ٦س
   

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9. ؒٓ٦عٝسؚٔٝؔلٖ٦ةכ葿ղ֮׷
   PO&SSPS3FUVSO
   PO&SSPS3FTVNF/FYU
   SFUSZ
   SFUSZ8IFO
   ˑؒٓ٦˒׏גז׿׌׏׋׏ֽ
   3Y+BWBךؒٓ٦عٝسؚٔٝ
   

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10. ؿ؋؎ָٕ鼅䫛ׁ׸גְזְךַ
    ؿ؋؎ָٕ《䖤דֹזַ׏׋ךַ
    ،حفٗ٦س㼎韋㢩ךؿ؋؎ٕ䕎䒭׌׏׋ךַ
    8FC؟٦غ٦ָتؐٝ׃גְ׷ךַ
    ؔؿٓ؎ٝזךַ
    ˑؒٓ٦˒ה♧〡ח鎉׏ג׮˘˘
    ،فٔה׃גˑ姻׃ְ˒䮙⹛כؒٓ٦
    

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11. RxBinding.clicks(button)
    .map { /* Get file */ }
    .flatMap { /* Upload */ }
    ~~~~~
    .subscribe({
    if (it.isSuccessful) {
    /* Success */
    } else {
    /* Request failure */
    }
    }, {
    /* IOException */
    })
    PO/FYUח3FTVMU㘗׫׋ְז׮ך׾굲לׅ
    

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12. PO/FYUח
    &JUIFS׾굲לׅ
    

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13. public abstract class Either {
    public static Either left(A a) {
    new Left<>(a);
    }
    public static Either right(B b) {
    new Right<>(b);
    }
    public abstract boolean isLeft();
    public abstract boolean isRight();
    public abstract X fold(Fold l,
    Fold r);
    }
    &JUIFSKBWB
    

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14. public class Left extends Either {
    private final A a;
    public Left(A a) { this.a = a; }
    @Override
    public boolean isLeft() { return true; }
    @Override
    public boolean isRight() { return false; }
    @Override
    public X fold(Fold l, Fold r) {
    return l.fold(a);
    }
    }
    -FGUKBWB 3JHIUKBWB
    
    

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15. public interface FoldJ {
    Y fold(X value);
    }
    'PMEKBWB
    

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16. &JUIFS
    אך㘗ךֲ׍ծְ׆׸ַ㘗ך⦼׾䭯א
    ؟ـؙٓأה׃ג-FGU3JHIU㘗ָ֮׷
    䧭⸆כ姻׃ְ SJHIU
    חַֽג3JHIUד鵤ׅ
    㣟侁כ-FGUד鵤ׅ
    3Y+BWBדכ-FGU׾5ISPXBCMFחׅ׷ה葺ׁ׉ֲ
    

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17. fun a(): Observable>
    = Observable.create {
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.right(“Hello”))
    it.onNext(Either.right(“World”))
    it.onNext(Either.right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    

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18. fun a(): Observable>
    = Observable.create {
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.right(“Hello”))
    it.onNext(Either.right(“World”))
    it.onNext(Either.right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    䧭⸆儗כ4USJOH 㣟侁儗כ5ISPXBCMF׾䭯א&JUIFS
    

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19. fun a(): Observable>
    = Observable.create {
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.right(“Hello”))
    it.onNext(Either.right(“World”))
    it.onNext(Either.right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    ⡦㔐ד׮㣟侁׾鵤ֿׅהָדֹ׷
    

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20. fun a(): Observable>
    = Observable.create {
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.left(RuntimeException()))
    it.onNext(Either.right(“Hello”))
    it.onNext(Either.right(“World”))
    it.onNext(Either.right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    ׮׍׹׿䧭⸆׮⡦㔐ד׮鵤ֿׅהָדֹ׷
    

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21. ⢽
    0CTFSWBCMFDSFBUF
    a().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    

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22. ⢽
    0CTFSWBCMFDSFBUF
    a().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    4VCTDSJCFSPO/FYUך⚥ח׮ֲ媮「ֽ〡׾⡲׷
    &JUIFS" #ד䭷㹀׃׋ˑ㘗˒ד穠卓׾「ֽ《׸׷
    

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23. 
    ,PUMJOד׮׏הأو٦زחדֹזְַז
    

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24. sealed class Either {
    abstract val isLeft: Boolean
    abstract val isRight: Boolean
    }
    &JUIFSLU
    

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25. &JUIFSLU
    data class Left(val value: A)
    : Either() {
    override val isLeft: Boolean = true
    override val isRight: Boolean = false
    }
    data class Right(val value: B)
    : Either() {
    override val isLeft: Boolean = false
    override val isRight: Boolean = true
    }
    

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26. &JUIFSLU
    inline fun Either.fold(
    left: (A) -> X,
    right: (B) -> X
    ): X = when (this) {
    is Left -> left(value)
    is Right -> right(value)
    }
    

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27. &JUIFSLU
    inline fun Either.fold(
    left: (A) -> X,
    right: (B) -> X
    ): X = when (this) {
    is Left -> left(value)
    is Right -> right(value)
    }
    ꟼ侧׾「ֽ《׏ג
    

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28. &JUIFSLU
    inline fun Either.fold(
    left: (A) -> X,
    right: (B) -> X
    ): X = when (this) {
    is Left -> left(value)
    is Right -> right(value)
    }
    XIFO䒭ד㘗ח䘔ׄג㹋遤ׅ׷ꟼ侧׾ⴖ׶剏ִ
    

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29. fun b(): Observable>
    = Observable.create {
    it.onNext(Left(RuntimeException()))
    it.onNext(Left(RuntimeException()))
    it.onNext(Left(RuntimeException()))
    it.onNext(Right(“Hello”))
    it.onNext(Right(“World”))
    it.onNext(Right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    

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30. fun b(): Observable>
    = Observable.create {
    it.onNext(Left(RuntimeException()))
    it.onNext(Left(RuntimeException()))
    it.onNext(Left(RuntimeException()))
    it.onNext(Right(“Hello”))
    it.onNext(Right(“World”))
    it.onNext(Right(“Foo Bar Buzz”))
    }
    ⢽
    0CTFSWBCMFDSFBUF
    刿חأحؗٔ剅ֻֿהָדֹ׷
    

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31. ⢽
    0CTFSWBCMFDSFBUF
    b().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    +BWBד㹀纏׃׋הֹה「ֽ《׶倯כずׄ
    

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32. ׁ׵ח
    typealias RxEither = Either
    typealias RxRight = Right
    typealias RxLeft = Left
    fun Observable.either():
    Observable> =
    map { RxRight(it) as RxEither }
    .onErrorReturn { RxLeft(it) }
    

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33. ׁ׵ח
    typealias RxEither = Either
    typealias RxRight = Right
    typealias RxLeft = Left
    fun Observable.either():
    Observable> =
    map { RxRight(it) as RxEither }
    .onErrorReturn { RxLeft(it) }
    -FGU㘗ָ5ISPXBCMFך㘗׾UZQFBMJBTד欽䠐
    

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34. ׁ׵ח
    typealias RxEither = Either
    typealias RxRight = Right
    typealias RxLeft = Left
    fun Observable.either():
    Observable> =
    map { RxRight(it) as RxEither }
    .onErrorReturn { RxLeft(it) }
    䭁䓸ꟼ侧ד0CTFSWBCMFFJUIFS׾欽䠐
    

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35. ׁ׵ח
    fun c(): Observable
    = Observable.create {
    it.onNext(“Hello, world”)
    it.onError(RuntimeException())
    }
    c().either().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    

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36. ׁ׵ח
    fun c(): Observable
    = Observable.create {
    it.onNext(“Hello, world”)
    it.onError(RuntimeException())
    }
    c().either().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    兛鸐ך0CTFSWBCMFָ֮׏ג׮
    

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37. ׁ׵ח
    fun c(): Observable
    = Observable.create {
    it.onNext(“Hello, world”)
    it.onError(RuntimeException())
    }
    c().either().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    䭁䓸ꟼ侧דFJUIFSؔلٖ٦ةך״ֲח䮶׷莸ֲ
    

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38. ׁ׵ח
    fun c(): Observable
    = Observable.create {
    it.onNext(“Hello, world”)
    it.onError(RuntimeException())
    }
    c().either().subscribe({ either ->
    either.fold({
    /* left, “it” is Throwable */
    }, {
    /* right, “it” is String */
    })
    }, {
    /* Error */
    })
    0CTFSWBCMFNFSHFזוד䕵甧א
    

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39. תה׭
    䟝㹀ⰻך㣟侁䟝㹀㢩ך㣟侁׾ⴓֽ׋ְ
    &JUIFS㘗׾⡲׏גⴓֽ׷ֿהָדֹ׷
    ؔلٖ٦ة٦דכזֻ㘗דⴓֽ׷
    ,PUMJO׾⢪ֲה刿חأو٦زח㹀纏דֹ׷
    䭁䓸ꟼ侧׾⢪׏ג傀㶷ך0CTFSWBCMF׮

    &JUIFS5ISPXBCMF 5ח㢌䳔〳腉
    &JUIFS荈⡤כ4DBMBח׮׏הؼٝزָ֮׷
    -FGU 3JHIUךNBQװTXBQזוזו
    

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40. ֶ׃תְ
    IUUQTHJUIVCDPNSZVHPP&JUIFS4BNQMF
    

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