Java臭くない かわいい小鳥にする話 - メルカリ JP のコード例を交え -

Nov. 22, 2017
Mercari × Souzoh Android Talk @mercari

Kotlin すでにバリバリ使ってるところも慎重になってるところもあるかなと思うんですが、学習コスト安く小さなコードで戦果の上がるかわいい言語なので頭の鈍くなってきたおじさんたちにこそ使ってみてほしい！っていうプレゼンしてみました。

Transcript

1. Javaष͘ͳ͍ ͔Θ͍͍খௗʹ͢Δ࿩ - ϝϧΧϦ JP ͷίʔυྫΛަ͑ - by @sintario Nov. 22, 2017 Mercari × Souzoh Android Talk @mercari
2. ͜͜·ͰΨν੎ͷ࿩Ͱ ർΕ·ͨ͠ΑͶʁ
3. ͳͷͰٳܜલͷ
 ͍ܰ࿩ʹ͠·͢Ͷ
4. ࣗݾ঺հ • @sintario (Chronum Sintario) • ϝϧΧϦࣾྺ22೔Ίͷ৽ਓΤϯδχΞ • ീԦࢠࢢࡏॅʢژԦઢͱେߐށઢͰձ͑ΔΑʣ • ࠷ۙͷझຯ͸Ոఉͷෆཁ඼ΛϝϧΧϦͰചΓ͞͹͍ ͯച্ۚͰࣗ෼༻ͷ͓΋ͪΌΛങ͍ړΔ͜ͱʢ௚ۙ ͸੟ˑ͓ʹ͍͞Μͷ࣋ͬͯͳ͍רΛະ࢖༻৽඼300ԁ റΓͰूΊ͍ͯ·ͨ͠ʣ
5. Career Background • JustSystems •Java, XML •ATOK Mac, Tweet ATOK, Objective-C, C++ • Lunascape •Web browser iOS app • DeNA •iOS apps, Android apps •Groovy, νϥγϧ, KenCoM, ͞ΜΆδελ •Healthcare, KenCoM, Ruby on Rails, Swift, Kotlin
6. ӈͷਓᐌ͘ http://mercan.mercari.com/entry/2017/09/28/130000
8. ̏̕೔ؒͷ༗څফԽΛܦͯϝϧΧϦ΁ ͦͷؒͣͬͱՈࣄख఻͍ ϝϧΧϦ࢖͍ࠐΜͰ·ͨ͠
9. Ͱɺٱ͠ͿΓʹ ίʔυॻ͍ͯΔΜ͕ͩ
10. Զͦ͏͍͑͹ ϨϏϡʔ͓͡͞ΜͩͬͨΘ
11. Kotlin Λ࢖ͬͯ ಡΊΔίʔυΛॻ͘࿩
12. ͳΜͰࠓ͞Βͦͷ࿩Αʁ
13. Android ͓͡͞Μͨͪʹ ݱ໾Ͱੜ͖࢒ͬͯཉ͍͠
14. W◦ntedly ͱ͔ݟΔͱ ͜͏͍͏ͷ͍ͬͺ͍ࡌͬͯΔ͚Ͳ ʮฐࣾ͸ฏۉ೥ྸ20୅Ͱ͢ʯ ʮຖि༵ۚ೔͸ŰƅŖžŖͯ͠·͢ʯ ͱ͔ͳΜͱ͔
15. पΓʹ̏̌ޙ൒ա͗ͨ ΤϯδχΞԿਓ͍ΔΑʁ ελʔτΞοϓͷࣾ௕ͱ͔CTOͱ͔ʹͳΔͷ͔ͳʁ ͳΕΔͷ͔ͳʁ ໘઀Ͱ10೥ޙԿ͠·͔ͬͯ͢ݴΘΕͯ౴͑ΒΕΔʁ Ϛωʔδϝϯτ΄Μͱʹ΍Γ͍ͨʁ
16. ͓ͬ͞Μ͕ ΤϯδχΞͱͯ͠ੜ͖࢒Δʹ͸ Α͘ރΕ͍ͯΔ͜ͱ͕େࣄ
17. Α͘ރΕ͍ͯΔͱ͸ • ແ೉ͳٕज़Ͱແ೉ʹ෺͕࡞ΕΔ • ଟগݹ͍஌ࣝΛ࢖͍·Θͯ͠एऀʹυϠΕΔ • ଟগ͸ษڧ΋·ͩͰ͖Δɺඈͼ͔ͭͳ͍͚Ͳ Ͱ͖Δ • ʢ࿝֐Β͘͠ͳ͍ײ͡Ͱ͋Δʣ
18. μϝͳރΕํ • ΋͏ͳΜʹ΋ษڧͰ͖ͳ͍Ͱ͢ •֮͑ͨݴޠͻͱͭͰҰੜ৯͍ͬͯ͘ʢJavaͷ ਓͱ͔ʣ •֮͑ͨΠσΟΦϜҎ֎͸޻෉΋Ͱ͖ͳ͘ͳΔ •ૣ͍ͱ΄Μͱʹ20୅ͱ͔Ͱ΋ؕͬͯ͠·͏
19. μϝͳރΕํ
20. ͦΜͳ Ѫ͢΂͖͓ͬ͞Μͨͪʹ Kotlin Λ঑Ί͍ͨ
21. Kotlin ͬͯ Կ͕͋Γ͕͍ͨͷʁ
22. ͓ͬ͞Μʹͱͬͯخ͍͜͠ͱ ͳΜͳͷʁ Kotlin ͬͯ Կ͕͋Γ͕͍ͨͷʁ
23. ʢ৽ͨʹʣ ֮͑Δ͜ͱ͕গͳ͍
24. ʢ৽ͨʹʣ ֮͑Δ͜ͱ͕গͳ͍ ݴޠ͕͍͍ҙຯͰශ૬
    ͚ͩͲͪΌΜͱݱ୅ޠ
    +BWB
    ͱ͔
    3VCZ
    ͱ͔
    4XJGU
    ॻ͍ͯͨਓͳΒ
    ࢀೖোน௿͍
25. ͿͬͪΌ͚ ͜Ε͚ͩ஌ͬͯΕ͹ ͍͍͓̺ͩͨ
26. ͿͬͪΌ͚ ͜Ε͚ͩ஌ͬͯΕ͹ ͍͍͓̺ͩͨ ?., .let, .apply, when, ?: return, companion object, fun
27. ͿͬͪΌ͚ ͜Ε͚ͩ஌ͬͯΕ͹ ͍͍͓̺ͩͨ ?., .let, .apply, when, ?: return, companion object, fun ͋ͱ͸ . ଧͬͯ Android Studio ઌੜʹڭ͑ͯ΋Β͍ͳ
28. ίϯύΫτͳݴ༿Ͱ Readable ͳ ίʔυ͕ॻ͚Δ
29. ݺΜͩʁಡΜͩʁ https://www.mercari.com/jp/search/? keyword=%E3%83%AA%E3%83%BC%E3%83%80%E3%83%96%E3%83%AB %E3%82%B3%E3%83%BC%E3%83%89 ষɹཧղ͠΍͍͢ίʔυ
    ষɹ໊લʹ৘ใΛ٧ΊࠐΉ
    ষɹޡղ͞Εͳ໊͍લ
    ষɹඒ͠͞
    ষɹίϝϯτ͢΂͖͜ͱΛ஌Δ
    ষɹίϝϯτ͸ਖ਼֬Ͱ؆ܿʹ
    ষɹ੍ޚϑϩʔΛಡΈ΍͘͢͢Δ
    ষɹڊେͳࣜΛ෼ׂ͢Δ
    ষɹม਺ͱಡΈ΍͢͞
    ষɹແؔ܎ͷԼҐ໰୊Λநग़͢Δ
    ষɹҰ౓ʹͭͷ͜ͱΛ
    ষɹίʔυʹࢥ͍ΛࠐΊΔ
    ষɹ୹͍ίʔυΛॻ͘
    ষɹςετͱಡΈ΍͢͞
    ষɹʮ෼ʗ࣌ؒΧ΢ϯλʯΛઃܭɾ࣮૷͢Δ
30. obvious by definition Readable ͳΒ ίʔυ͕ಡΈ΍͍͢
31. Readable ͳΒ ͍·͞Β ίʔσΟϯάͷఴ࡟͞Εͳ͍
32. Readable ͳΒ ϏδωεϩδοΫʹ ूதͰ͖Δ
33. Readable ͳΒ ϏδωεϩδοΫʹ ूதͰ͖Δ ॻ͋͘ͳͨ΋ɺಡΉ஥ؒ΋
34. Readable ͳίʔυ͕ ॻ͚Δίʔμʔ͸ ࢌ͑ΒΕΔ
36. ͭ·Γ
37. Readable ͸ ͓͍͍͠
38. ͓͍͍͠ࢥ͍Λͤͯ͘͞ΕΔ Kotlin ͕͔Θ͍͘ͳΔ
39. খௗ ,PUMJO
40. ͕͔ͩ͠͠
41. ͓ͬ͞Μ͸ ֶशݶք໨લͳͷͰ ಓ۩͚ͩ༩͑ΒΕΔͱ ܦݧͷԆ௕ઢ্Ͱ͔͠ ࢖͑ͳ͔ͬͨΓ͢Δͷͩʂ
42. ྫ͑͹ ͜Μͳ Java ͕ ͋ͬͨͱ͢Δ͡Όͳ͍Ͱ͔͢ʔ
43. public class ModalContentWebActivity extends SchemeWebActivity { public static Intent createIntent(Context context, String url){ return createIntent(context, url, null, null); } public static Intent createIntent(Context context, String url, String funcName, String params){ Intent intent = new Intent(context, ModalContentWebActivity.class); intent.putExtra(S.url, url); intent.putExtra(S.funcName, funcName); intent.putExtra(S.params, params); return intent; }
44. Kotlinize it
45. ͦͨ͠Β͞ʔ ૉͷ͓ͬ͞Μ͸ ͖ͬͱ͜Μͳͷॻ͘ΜͩΑͶʔ
46. public class ModalContentWebActivity extends SchemeWebActivity { public static Intent createIntent(Context context, String url){ return createIntent(context, url, null, null); } public static Intent createIntent(Context context, String url, String funcName, String params){ Intent intent = new Intent(context, ModalContentWebActivity.class); intent.putExtra(S.url, url); intent.putExtra(S.funcName, funcName); intent.putExtra(S.params, params); return intent; }
47. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?): Intent { return createIntent(context, url, null, null) } fun createIntent(context: Context, url: String?, funcName: String?, params: String?): Intent { val intent = Intent(context, ModalContentWebActivity::class.java) intent.putExtra(S.url, url) intent.putExtra(S.funcName, funcName) intent.putExtra(S.params, params) return intent }
48. ͔Θ͍͘ͳ͍খௗ ୸Ր
    +BWB
    ͷʹ͓͍͕͵͚ͳ͍
49. ·ͣ σϑΥϧτҾ਺ͬͯͷ͕ ͋ͬͯͳ
50. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?): Intent { return createIntent(context, url, null, null) } fun createIntent(context: Context, url: String?, funcName: String?, params: String?): Intent { val intent = Intent(context, ModalContentWebActivity::class.java) intent.putExtra(S.url, url) intent.putExtra(S.funcName, funcName) intent.putExtra(S.params, params) return intent }
51. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { val intent = Intent(context, ModalContentWebActivity::class.java) intent.putExtra(S.url, url) intent.putExtra(S.funcName, funcName) intent.putExtra(S.params, params) return intent }
52. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { val intent = Intent(context, ModalContentWebActivity::class.java) intent.putExtra(S.url, url) intent.putExtra(S.funcName, funcName) intent.putExtra(S.params, params) return intent } overload ؔ਺ফ͑ͨʂ໌ࣔఆٛҰݸ࡟ݮ
53. apply ͠·͠ΐ͏ͥ
54. apply ͠·͠ΐ͏ͥ /** * Calls the specified function [block] with `this` value as its receiver * and returns `this` value. */ @kotlin.internal.InlineOnly public inline fun <T> T.apply(block: T.() -> Unit): T { block(); return this }
55. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { val intent = Intent(context, ModalContentWebActivity::class.java) intent.putExtra(S.url, url) intent.putExtra(S.funcName, funcName) intent.putExtra(S.params, params) return intent }
56. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { return Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) } }
57. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { return Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) } } ͜ͷதͰ͸ this ͕ Intent ΠϯελϯεͳͷͰ Ϩγʔόʔهड़Λল͚Δ
58. ॻ͖׳ΕΔͨΊͷίπͱͯ͠͸ ࠷ॳʹ return Hoge() ͬͯॻ͍ͪΌ͔ͬͯΒޙஔम ০͢Δߟ͑Ͱ΍Δͱ͍͍͔΋ ͋ͱ͸ val/var ͷΑ͏ͳҰ࣌ม਺ʹड͚औΔߟ͑Λ ࣺͯΔ͜ͱ
59. ୯Ұࣜؔ਺͸͞Βʹ
60. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null): Intent { return Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) } }
61. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null) = Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) }
62. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null) = Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) } ࣜͷ໭Γ஋Λฦ͢Αɺͱ͍͏௚ײతͳදݱʹɻ return ͱ͔΋͸΍ॻ͍ͨΒಐః
63. ࠷ॳͱൺֱ͠·͠ΐ͏
64. public class ModalContentWebActivity extends SchemeWebActivity { public static Intent createIntent(Context context, String url){ return createIntent(context, url, null, null); } public static Intent createIntent(Context context, String url, String funcName, String params){ Intent intent = new Intent(context, ModalContentWebActivity.class); intent.putExtra(S.url, url); intent.putExtra(S.funcName, funcName); intent.putExtra(S.params, params); return intent; }
65. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null) = Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) }
66. class ModalContentWebActivity: SchemeWebActivity() { companion object { fun createIntent(context: Context, url: String?, funcName: String? = null, params: String? = null) = Intent(context, ModalContentWebActivity::class.java).apply { putExtra(S.url, url) putExtra(S.funcName, funcName) putExtra(S.params, params) } ΋ͷ͛͑͢ߦ਺ݮΔͶ͑ จࣈ਺ݮΔͶ͑
67. վΊͯಡΜͰΈΔͱϚδ͍͍ຊ https://www.mercari.com/jp/search/? keyword=%E3%83%AA%E3%83%BC%E3%83%80%E3%83%96%E3%83%AB %E3%82%B3%E3%83%BC%E3%83%89 ষɹཧղ͠΍͍͢ίʔυ
    ষɹ໊લʹ৘ใΛ٧ΊࠐΉ
    ষɹޡղ͞Εͳ໊͍લ
    ষɹඒ͠͞
    ষɹίϝϯτ͢΂͖͜ͱΛ஌Δ
    ষɹίϝϯτ͸ਖ਼֬Ͱ؆ܿʹ
    ষɹ੍ޚϑϩʔΛಡΈ΍͘͢͢Δ
    ষɹڊେͳࣜΛ෼ׂ͢Δ
    ষɹม਺ͱಡΈ΍͢͞
    ষɹແؔ܎ͷԼҐ໰୊Λநग़͢Δ
    ষɹҰ౓ʹͭͷ͜ͱΛ
    ষɹίʔυʹࢥ͍ΛࠐΊΔ
    ষɹ୹͍ίʔυΛॻ͘
    ষɹςετͱಡΈ΍͢͞
    ষɹʮ෼ʗ࣌ؒΧ΢ϯλʯΛઃܭɾ࣮૷͢Δ
68. ͱ͍͏͜ͱͰ • খௗ͔Θ͍͍Αখௗ • ංେͨ͠ෛ࠴Λฦࡁ͢Δ͍ͭͰʹɺ͔Θ͍͍ίʔυʹɻ • ͔Θ͍͍খௗ͸ಡΈ΍͍͢Αɻ • Kotlin Β͘͠খ͔͚ͨ͘͞Β͓͡͞Μ·͍ͩΔΑͬͯݴ͑ ͦ͏ • ฐࣾͰ΋ Kotlin ԽΛ͢͢Ί͍ͯ·͢ͳ͏ʢPRϨϏϡʔͰ َͷΑ͏ʹఴ࡟͍ͯ͠·͢ʣ