プログラミング言語 Kotlinの紹介

コンこん会で発表した資料です。

Transcript

1. ϓϩάϥϛϯάݴޠ Kotlinͷ঺հ 
   ૣҴాେֶཧ޻ֶज़Ӄ
   ίϯϐϡʔλ࠙࿩ձ
   
 ௕ᖒ
   ଠ࿠
   !OHTX@UBSP ͜ͱΓΜ
2. ࣗݾ঺հ w ௕ᖒ
   ଠ࿠
   !OHTX@UBSP
   w ਂᖒݚڀࣨ
   ೥ଔۀ ֶ෦
   w ࣗশ,PUMJOΤόϯδΣϦετ
   w ޷͖ͳ΋ͷ
   ɺ
3. ΞδΣϯμ 
   +BWBͰ๊͑Δ໰୊
   
   ,PUMJOొ৔
4. 1. JavaͰ๊͑Δ໰୊
5. w ߴੑೳɾߴ৴པੑͷ+BWBԾ૝Ϛγϯ
   w ਐԽΛଓ͚Δϓϩάϥϛϯάݴޠ
   w ͔͠΋ޙํޓ׵ੑΛҡ࣋
   w ྺ࢙௕͍ɺਓޱଟ͍
   w ϥΠϒϥϦɾϑϨʔϜϫʔΫଟ͍ Javaૉఢ
6. w ৑௕ɺϘΠϥʔϓϨʔτ
   w OVMMϙΠϯλͷٯࢀর໰୊
   w ܕ҆શੑͷ໰୊ ͔͠͠ɺͦͷ൓໘
7. ৑௕ MyFavoriteService<Fruit> s =! new MyFavoriteService<>(banana);
8. ϘΠϥʔϓϨʔτ public final class Fruit {! ! private final String name;! ! private final int price;! ! private final Country country;! ! public Fruit(final String name, final int price, final Country country) {! this.name = name;! this.price = price;! this.country = country;! }! ! public String getName() {! return name;! }! ! public int getPrice() {! return price;! }! ! public Country getCountry() {! return country;! }! ! public Fruit withName(final String name) {! return new Fruit(name, price, country);! }! ! public Fruit withPrice(final int price) {! return new Fruit(name, price, country);! }! ! public Fruit withCountry(final Country country) {! return new Fruit(name, price, country);! }! ! // toStringͱ͔! // equalsͱ͔! // hashCodeͱ͔! ! public static Builder builder() {! return new Builder();! }! ! public static class Builder {! ! private String name;! ! private int price;! ! private Country country;! ! public Fruit build() {! return new Fruit(name, price, country);! }! ! public Builder name(final String name) {! this.name = name;! return this;! }! ! public Builder price(final int price) {! this.price = price;! return this;! }! ! public Builder country(final Country country) {! this.country = country;! return this;! }! }! } 'SVJUͷఆٛ w QSJWBUF
   pOBMϑΟʔϧυ
   w ίϯετϥΫλ
   w HFUUFS
   w UP4USJOH
   FRVBMT
   IBTI$PEF
   w #VJMEFSΫϥε
9. nullϙΠϯλͷٯࢀর String s = null;! s.toUpperCase(); /VMM1PJOUFS&YDFQUJPO
10. NPE͕ݏͳΒ nullνΣοΫ͢Ε͹͍͍͡Όͳ͍ String s = Ṗͷϝιου();! String upperCase = (s != null)! ? s.toUppserCase()! : null;
11. ͦΕຊ౰ʁ String s = reverse("Hello");! String upperCase = (s != null)! ? s.toUppserCase()! : null;
12. ͦΕຊ౰ʁ String s = reverse("Hello");! String upperCase = (s != null)! ? s.toUppserCase()! : null; OVMM͸ฦ͞ͳͦ͏ɻ
    ͱ͍͏͔࣮ࡍฦ͞ͳ͍
13. nullͳͷ͔ null͡Όͳ͍ͷ͔ Θ͔Βͳ͍
14. ͱΓ͋͑ͣJavaతͳ޻෉ @Nonnull! String reverse(String s) {…}! ! ! Optional<Character>! initial(String s) {…}
15. ୭ʹ΋null͸ࢭΊΒΕͳ͍ʂ @Nonnull! Optional<Foo> findFoo() {! return null;! }
16. ܕ҆શੑͷ໰୊ Integer[] ints = { 0 };! Number[] nums = ints;! nums[0] = 0.5;
17. ܕ҆શੑͷ໰୊ Integer[] ints = { 0 };! Number[] nums = ints;! nums[0] = 0.5; ໌Β͔ʹϚζ͍ૢ࡞ͳͷʹ
    ίϯύΠϥ͸ؾ෇͔ͳ͍
18. ܕ҆શ͚ͩͲ List<Integer> ints = immutableListOf(1);! ! List<? extends Number> nums = ints; ڞมͷ໌ࣔతͳࢦఆ
    ৑௕
19. w ΋ͬͱ୹͘ɺಡΈ΍͍͢ίʔυΛॻ͖ ͍ͨ
    w ҆શͳίʔυΛॻ͖͍ͨɻةݥͳίʔ υ͸ίϯύΠϧλΠϜʹ஄͍ͯཉ͍͠ ࢥ͏͜ͱ
20. 2. Kotlinొ৔
21. w ೥Նʹ+FU#SBJOTʹΑΓൃද
    w Φʔϓϯιʔε
    "QBDIF
    -JDFOTF
    
    w +7.ݴޠɺBMU+4ɺ"OESPJE΋αϙʔτ
    w +BWBࢿ࢈Λ׆͔ͤΔ
    w ੩తܕ෇͚ΦϒδΣΫτࢦ޲ݴޠ Kotlinͱ͸
22. w ৑௕ɺϘΠϥʔϓϨʔτ
    w OVMMϙΠϯλͷٯࢀর໰୊
    w ܕ҆શੑͷ໰୊ Kotlinͷ౴͑
23. ܕਪ࿦ // Java! MyFavoriteService<Fruit> s =! new MyFavoriteService<>(banana);! ! ! // Kotlin! val s = MyFavoritesService(banana)
24. ϘΠϥʔϓϨʔτ public final class Fruit {! ! private final String name;! ! private final int price;! ! private final Country country;! ! public Fruit(final String name, final int price, final Country country) {! this.name = name;! this.price = price;! this.country = country;! }! ! public String getName() {! return name;! }! ! public int getPrice() {! return price;! }! ! public Country getCountry() {! return country;! }! ! public Fruit withName(final String name) {! return new Fruit(name, price, country);! }! ! public Fruit withPrice(final int price) {! return new Fruit(name, price, country);! }! ! public Fruit withCountry(final Country country) {! return new Fruit(name, price, country);! }! ! // toStringͱ͔! // equalsͱ͔! // hashCodeͱ͔! ! public static Builder builder() {! return new Builder();! }! ! public static class Builder {! ! private String name;! ! private int price;! ! private Country country;! ! public Fruit build() {! return new Fruit(name, price, country);! }! ! public Builder name(final String name) {! this.name = name;! return this;! }! ! public Builder price(final int price) {! this.price = price;! return this;! }! ! public Builder country(final Country country) {! this.country = country;! return this;! }! }! } data public class Fruit(! val name: String,! val price: Int,! val country: Country! )
25. nullϙΠϯλͷٯࢀর // Java! String s = null;! s.toUpperCase();! ! // Kotlin! val s1: String = null! val s2: String? = null! s2.toUppserCase()
26. nullϙΠϯλͷٯࢀর // Java! String s = null;! s.toUpperCase();! ! // Kotlin! val s1: String = null! val s2: String? = null! s2.toUppserCase() /1&
27. nullϙΠϯλͷٯࢀর // Java! String s = null;! s.toUpperCase();! ! // Kotlin! val s1: String = null! val s2: String? = null! s2.toUppserCase() ίϯύΠϧΤϥʔ
    ௨ৗͷܕͷม਺ʹɺ
    OVMM͸୅ೖͰ͖ͳ͍
28. nullϙΠϯλͷٯࢀর // Java! String s = null;! s.toUpperCase();! ! // Kotlin! val s1: String = null! val s2: String? = null! s2.toUppserCase() ܕ
    ͸OVMMͰ΋0,
29. nullϙΠϯλͷٯࢀর // Java! String s = null;! s.toUpperCase();! ! // Kotlin! val s1: String = null! val s2: String? = null! s2.toUppserCase() ίϯύΠϧΤϥʔ
    ܕ
    ʹର͢Δٯࢀর͸
    ؾܰʹͰ͖ͳ͍ʂ
30. KotlinͰ͸ null͔൱͔Λ໌֬ ʹ۠ผ͢Δ ࢀߟ
    IUUQTTQFBLFSEFDLDPNOUBSPLPUMJOOVNCFSTIJCVJHVKWN
31. ܕ҆શ val ints: Array<Int> = arrayOf(0)! ! val nums: Array<Number> = ints ίϯύΠϧΤϥʔ
    +BWBελΠϧͷ഑ྻ͸ͳ͍ɻ
    δΣωϦΫεͰදݱɻ
32. ܕࣗମʹมҐࢦఆͰ͖Δ val ints: List<Int> = listOf(0)! ! val nums: List<Number> = ints JOUFSGBDF
    -JTUPVU
    &
    ͷΑ͏ʹܕͷఆٛ࣌ʹ
    มҐΛࢦఆͰ͖Δ
33. w ͔ͳΓ୹͘ɺಡΈ΍͍͢ίʔυ͕ॻ͚ ͦ͏ɻ
    w ܕͷҧ͍΍OVMMʹΑΔ࣮ߦ࣌ΤϥʔΛ๷ ͍Ͱ҆શͳίʔυ͕ॻ͚ͦ͏ɻ ࢥ͏͜ͱ
34. ͦͷଞͷಛ௕ w ֦ுؔ਺
    ੩తʹطଘܕʹϝιουΛੜ΍ͤ ΔΑ͏ͳ΍ͭ
    w ߴ֊ؔ਺ɺؔ਺ΦϒδΣΫτɺϥϜμࣜ
    w +BWBͱͷ૬ޓӡ༻ੑ ໨ඪ
    w +BWBͱಉ౳ͷίϯύΠϧ଎౓ ໨ඪ
    w "OESPJE։ൃΛެࣜαϙʔτ
35. w ҆ఆ൛
    ະϦϦʔε
    ݱࡏ
    WFS
    w *%&ͷิॿ͕+BWBͱൺֱͯ͠·ͩऑ͍
    w ਓޱɺೝ஌౓͕े෼Ͱͳ͍ ୹ॴ
36. ·ͱΊ JavaͰ΋ΜʹΐΓ͢ Δͱ͜ΖɺKotlinͰ͸ ΠΠײ͡ʹͳͬͯΔΑ
37. w IUUQUSZLPUMJOMBOHPSH
    w खܰʹࢼͤΔ࣮ߦ؀ڥ
    w ͪΐͬͱ͚ͩಋೖ
    w ςετίʔυ͚ͩɺ6UJMతͳ΍͚ͭͩ
    w +BWBͱͷڞଘ͕༰қͳͷͰ ·ͣ࢝ΊΑ͏
38. ͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ Let’s enjoy Kotlin!