読みやすいコードの書き方 第 6 回 / Code readability: Session 6 (ver. 2, Ja)

第 6 回: 依存関係 I

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セッションリスト

第 1 回: 導入と原則
- https://speakerdeck.com/munetoshi/code-readability-session-1-ver-2-ja

第 2 回: 命名
- https://speakerdeck.com/munetoshi/code-readability-session-2-ver-2-ja

第 3 回: コメント
- https://speakerdeck.com/munetoshi/code-readability-session-3-ver-2-ja

第 4 回: 状態
- https://speakerdeck.com/munetoshi/code-readability-session-4-ver-2-ja

第 5 回: 関数
- https://speakerdeck.com/munetoshi/code-readability-session-5-ver-2-ja

第 6 回: 依存関係 I
- https://speakerdeck.com/munetoshi/code-readability-session-6-ver-2-ja

第 7 回: 依存関係 II
- https://speakerdeck.com/munetoshi/code-readability-session-7-ver-2-ja

第 8 回: レビュー
- https://speakerdeck.com/munetoshi/code-readability-session-8-ver-2-ja

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関連書籍 「読みやすいコードのガイドライン - 持続可能なソフトウェア開発のために」
- https://gihyo.jp/book/2022/978-4-297-13036-7

英語版のリスト: https://gist.github.com/munetoshi/65a1b563fb2c271f328c121a4ac63571#file-code-readability-links-md

以前のバージョン (英語): https://speakerdeck.com/munetoshi/code-readability

© 2019-2023 Munetoshi Ishikawa, supported by LINE corporation

Transcript

1. ಡΈ΍͍͢ίʔυͷॻ͖ํˠୈ 6 ճ ґଘؔ܎ ‐
2. લճͷ͓͞Β͍: ؔ਺ ཁ໿Λॻ͍ͯؔ਺͕ཧղ͠΍͍͔֬͢ೝ͢Δ ؔ਺ͷ੹೚: - ඞཁͳΒ෼ׂ͢Δ - ϝΠϯͷ݁ՌΛฦ͢ͱ͖͸มߋ͠ͳ͍ ؔ਺ͷྲྀΕ: - ఆٛࢦ޲ϓϩάϥϛϯά, ΞʔϦʔϦλʔϯ, ର৅ʹΑΔ෼ׂ
3. ߨٛͷߏ੒ - ಋೖͱݪଇ - ࣗવݴޠ: ໋໊, ίϝϯτ - ܕͷߏ଄: ঢ়ଶ, ؔ਺ - ܕؒͷߏ଄: ґଘؔ܎I, ґଘؔ܎II - ϨϏϡʔ ґଘؔ܎ > ಋೖ
4. ʮґଘؔ܎ʯͱ͸ 1/2 ྫ: Ϋϥε X ͕ Y ʹґଘ͍ͯ͠Δঢ়گ - X ͕ Y ͷΠϯελϯεΛϓϩύςΟͱͯ࣋ͭ͠ - X ͷϝιου͕ Y ΛҾ਺ɾ໭Γ஋ ͱͯ͠࢖͏ - X ͕ Y ͷϝιουΛݺͼग़͢ - X ͕ Y Λܧঝ͢Δ ͓͓Αͦ X தʹʮYʯ͕ग़ݱ 㱺 X ͸ Y ʹґଘ͍ͯ͠Δ ґଘؔ܎ > ಋೖ
5. ʮґଘؔ܎ʯͱ͸ 2/2 ґଘؔ܎͸Ϋϥεಉ࢜ͷΈͰൃੜ͢Δʁ No Πϯελϯεɾؔ਺ɾϞδϡʔϧؒͰ΋ى͖Δ Ұ໨Ͱ͸Θ͔Γʹ͍͘ґଘؔ܎΋͋Δ ґଘؔ܎ > ಋೖ
6. ґଘؔ܎ IɾII ͷ಺༰ ґଘؔ܎ I: - ݁߹౓ ґଘؔ܎ II: - ํ޲ - ॏෳ - ໌ࣔੑ ґଘؔ܎ > ಋೖ
7. ґଘؔ܎ IɾII ͷ಺༰ ґଘؔ܎ I: - ݁߹౓ ґଘؔ܎ II: - ํ޲ - ॏෳ - ໌ࣔੑ ґଘؔ܎ > ݁߹౓
8. ݁߹౓ ґଘؔ܎ͷڧ͞Λࣔ͢ई౓ ऑ͍݁߹͕޷·͍͠ ΦϦδφϧͷఆٛ7Ͱ͸ؔ਺ؒͷґଘͷڧ͞Λࣔ͢ ͜ͷϓϨθϯςʔγϣϯͰ͸Ϋϥεؒͷؔ܎ʹ֦ு͢Δ 7 Glenford J. Myers. 1975. Reliable software though composite design. Litton Educational Publishing, Inc. ґଘؔ܎ > ݁߹౓
9. ݁߹౓ 2/2 (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Content coupling) (Common coupling) (External coupling) ґଘؔ܎ > ݁߹౓
10. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Common coupling) (Content coupling) (External coupling) ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
11. ಺༰݁߹ ίʔυ಺෦ͷৼΔ෣͍ʹґଘ͢Δؔ܎ - ίʔυͷ಺෦ʹ௚઀δϟϯϓ͢Δ - Ӆṭ͞Εͨঢ়ଶΛ௚઀มߋ͢Δ - ಈ࡞Λ௚઀ॻ͖׵͑Δ ۙ୅తͳϓϩάϥϛϯάݴޠͰ͸༰қʹͰ͖ͳ͍ ͨͩ͠ɺʮࣅͨΑ͏ͳʯৼΔ෣͍͸࡞Εͯ͠·͏ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
12. ಺༰݁߹ͱಉ౳ͷ݁߹ - ෆਖ਼ͳ࢖͍ํͷڐ༰ - ಺෦ͷՄมͳঢ়ଶͷڞ༗ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
13. ಺༰݁߹ͱಉ౳ͷ݁߹ - ෆਖ਼ͳ࢖͍ํͷڐ༰ - ಺෦ͷՄมͳঢ়ଶͷڞ༗ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
14. ෆਖ਼ͳ࢖͍ํͷڐ༰: Α͘ͳ͍ྫ class Caller { fun callCalculator() { calculator.calculate() ... ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
15. ෆਖ਼ͳ࢖͍ํͷڐ༰: Α͘ͳ͍ྫ class Caller { fun callCalculator() { calculator.parameter = 42 calculator.calculate() val result = calculator.result ... ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
16. ෆਖ਼ͳ࢖͍ํͷڐ༰: Α͘ͳ͍ྫ class Caller { fun callCalculator() { calculator.parameter = 42 calculator.prepare() calculator.calculate() calculator.tearDown() val result = calculator.result ... ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
17. ෆਖ਼ͳ࢖͍ํͷڐ༰: Կ͕ʮΑ͘ͳ͍ʯ͔ calculator ͷ࢖͍ํΛؒҧ͍΍͍͢ - prepare()ɾtearDown() Λਖ਼͘͠ݺͿඞཁ͕͋Δ - ஋Λड͚౉͠ʹ parameter/result Λ࢖͏ඞཁ͕͋Δ ࢓༷ͷมߋʹରͯ͠ؤ݈Ͱͳ͍ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
18. ෆਖ਼ͳ࢖͍ํͷڐ༰: मਖ਼ํ๏ - ݺͼग़͠ॱͷ੍໿ΛӅ͢ - ஋ͷड͚౉͠ʹҾ਺ɾ໭Γ஋Λ࢖͏ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
19. ෆਖ਼ͳ࢖͍ํͷڐ༰: मਖ਼ྫ class Caller { fun callCalculator() { val result = calculator.calculate(42) ... class Calculator { fun calculate(type: Int): Int { prepare() ... tearDown() return ... ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
20. ෆਖ਼ͳ࢖͍ํͷڐ༰: ֬ೝ͢΂͖఺ σβΠϯίϯηϓτ΍ݪଇΛա৒ʹద༻͠ͳ͍ - ྫ: ίϚϯυɾΫΤϦ෼཭ͷݪଇ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
21. ಺༰݁߹ͱಉ౳ͷ݁߹ - ෆਖ਼ͳ࢖͍ํͷڐ༰ - ಺෦ͷՄมͳঢ়ଶͷڞ༗ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
22. ಺෦ͷՄมͳঢ়ଶͷڞ༗: ʮΑ͘ͳ͍ʯྫ class UserListPresenter(val userList: List<UserData>) { fun refreshViews() { /* ... */ } class Caller { val userList: MutableList<UserData> = mutableListOf() val presenter = UserListPresenter(userList) ... fun addUser(newUser: UserData) { userList += newUser presenter.refreshViews() ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
23. ಺෦ͷՄมͳঢ়ଶͷڞ༗: Կ͕ʮΑ͘ͳ͍ʯ͔ UserListPresenter ͕֎෦ͷՄมͳঢ়ଶʹґଘ͍ͯ͠Δ - ଞͷ userList ͷॴ༗ऀʹΑͬͯҙਤͤͣঢ়ଶ͕ߋ৽͞ΕΔ - userList ͷมߋํ๏ͷ੍໿ʢ௥Ճɾ࡟আ౳ʣʹ੍໿͕ͳ͍ ෆਖ਼ͳঢ়ଶΛ࡞Γ΍͘͢ɺόάͷௐࠪ΋ࠔ೉ - UserListPresenter ͷࢀরͳ͠ʹߋ৽Մೳ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
24. ಺෦ͷՄมͳঢ়ଶͷڞ༗: मਖ਼ํ๏ - ෆมͳ஋ɾ஋ͷෳ੡ɾίϐʔΦϯϥΠτΛར༻͢Δ - ঢ়ଶΛߋ৽͢ΔͨΊͷΠϯλʔϑΣΠεΛ࡞Δ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
25. ಺෦ͷՄมͳঢ়ଶͷڞ༗: मਖ਼ྫ class UserListPresenter { val userList: MutableList<UserData> = mutableListOf() fun addUsers(newUsers: List<UserData>) { userList += newUsers // Update views with `userList` } (addUsers ͕ΞτϛοΫͳΒ) newUsers ͕ՄมͰ͋ͬͯ΋໰୊ͳ͍ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
26. ಺෦ͷՄมͳঢ়ଶͷڞ༗: ֬ೝ͢΂͖఺ ঢ়ଶͷॴ༗ऀΛ໌֬ʹ͢Δ ࣮ݱํ๏: - ॴ༗ऀͷΠϯλʔϑΣΠεΛ௨ͯ͠ঢ়ଶΛߋ৽͢Δ - Մมͳঢ়ଶΛ؅ཧ͢ΔΫϥεΛ࡞੒͢Δ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
27. ಺༰݁߹: ·ͱΊ ಺෦ͷಈ࡞ʹґଘͨ͠ίʔυΛ࡞Βͳ͍ - ʮෆਖ਼ͳ࢖͍ํʯ͕Ͱ͖ͳ͍Α͏ʹ͢Δ - Մมͳঢ়ଶͷॴ༗ऀΛ໌֬ʹ͢Δ ґଘؔ܎ > ݁߹౓ > ಺༰݁߹
28. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Common coupling) (External coupling) (Content coupling) ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
29. ڞ௨݁߹ɾ֎෦݁߹ ՄมͳάϩʔόϧσʔλΛڞ༗͢Δؔ܎ - άϩʔόϧม਺ʹΑΔ஋ͷड͚౉͠ - Մมͳγϯάϧτϯʹର͢Δґଘ - (ϑΝΠϧγεςϜɾωοτϫʔΫ౳ͷڞ༗Ϧιʔεͷར༻) ڞ௨݁߹: σʔλߏ଄ͷڞ༗, ֎෦݁߹: جຊܕͷ஋ͷڞ༗ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
30. ڞ௨݁߹ɾ֎෦݁߹ ՄมͳάϩʔόϧσʔλΛڞ༗͢Δؔ܎ - άϩʔόϧม਺ʹΑΔ஋ͷड͚౉͠ - Մมͳγϯάϧτϯʹର͢Δґଘ - (ϑΝΠϧγεςϜɾωοτϫʔΫ౳ͷڞ༗Ϧιʔεͷར༻) ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
31. άϩʔόϧม਺ͷར༻: ʮΑ͘ͳ͍ʯྫ var parameter: Int? = null var result: Int? = null class Calculator { fun calculate() { result = parameter + ... fun callCalculator() { parameter = 42 calculator.calculate() ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
32. άϩʔόϧม਺ͷར༻: Կ͕ʮΑ͘ͳ͍ʯ͔ ஋ͱݺͼग़͠ͷؔ܎ੑ੍͕໿͞Εͳ͍ - ಉ࣌ʹෳ਺ճͷݺͼग़͠Λ͢Δ͜ͱͰյΕΔ - ෆਖ਼ͳঢ়ଶΛ࡞Γ΍͍͢ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
33. άϩʔόϧม਺ͷར༻: मਖ਼ํ๏ ஋ΛҾ਺΍໭Γ஋Ͱड͚౉͢͠Δ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
34. άϩʔόϧม਺ͷར༻: मਖ਼ྫ class Calculator { fun calculate(parameter: Int): Int = parameter + ... fun callCalculator() { val result = calculator.calculate(42) ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
35. ڞ௨݁߹ɾ֎෦݁߹ ՄมͳάϩʔόϧσʔλΛڞ༗͢Δؔ܎ - άϩʔόϧม਺ʹΑΔ஋ͷड͚౉͠ - Մมͳγϯάϧτϯʹର͢Δґଘ - (ϑΝΠϧγεςϜɾωοτϫʔΫ౳ͷڞ༗Ϧιʔεͷར༻) ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
36. Մมͳγϯάϧτϯͷར༻: ʮΑ͘ͳ͍ʯྫ val USER_DATA_REPOSITORY = UserDataRepository() class UserListUseCase { suspend fun invoke(): List<User> = withContext(...) { val result = USER_DATA_REPOSITORY.query(...) ... ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
37. Մมͳγϯάϧτϯͷར༻: Կ͕ʮΑ͘ͳ͍ʯ͔ γϯάϧτϯ͸؅ཧ͕ࠔ೉ - γϯάϧτϯͷϥΠϑαΠΫϧɾείʔϓɾࢀরͷ؅ཧ͕ࠔ೉ - ࢓༷ͷมߋʹର͢Δॊೈੑ͕௿͍ - γϯάϧτϯΛ࢖͏ίʔυͷςετ͕೉͍͠ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
38. Մมͳγϯάϧτϯͷར༻: मਖ਼ํ๏ ΠϯελϯεΛίϯετϥΫλύϥϝʔλͱͯ͠౉͢ ( ґଘੑͷ஫ೖ) ίϯετϥΫλΛݺͼग़͢ଆͰΠϯελϯεΛ؅ཧՄೳ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
39. Մมͳγϯάϧτϯͷར༻: मਖ਼ྫ class UserListUseCase( val userDataRepository: UserDataRepository ) { suspend fun invoke(): List<User> = withContext(...) { val result = userDataRepository.query(...) ... ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
40. ڞ௨݁߹ɾ֎෦݁߹: ิ଍ ΑΓখ͍͞είʔϓʹରͯ͠΋ಉٞ͡࿦Λద༻Մೳ - ϞδϡʔϧɾύοέʔδɾΫϥε... ྫ: ΠϯελϯεϓϩύςΟʹΑΔ஋ͷड͚౉͠Λආ͚Δ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
41. Ϋϥε಺ͷڞ௨݁߹ɾ֎෦݁߹: ʮΑ͘ͳ͍ʯྫ class Klass { var parameter: Int? = null fun firstFunction() { parameter = 42 secondFunction() } fun secondFunction() { /* Use `parameter` here... */ } ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
42. Ϋϥε಺ͷڞ௨݁߹ɾ֎෦݁߹: मਖ਼ྫ class Klass { fun firstFunction() { val argument = 42 secondFunction(argument) } fun secondFunction(parameter: Int) { /* Use `parameter` here... */ } ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
43. ڞ௨݁߹ɾ֎෦݁߹: ·ͱΊ Մมͳγϯάϧτϯ΍άϩʔόϧม਺Λ࢖Θͳ͍ - ؅ཧ΍ςετ͕೉͍͠ɾมߋͷӨڹൣғ͕େ͖͍ ڞ௨݁߹ɾ֎෦݁߹ͷճආํ๏: - ஋ͷड͚౉͠ʹҾ਺΍໭Γ஋Λ࢖͏ - ґଘੑͷ஫ೖΛߦ͏ ґଘؔ܎ > ݁߹౓ > ڞ௨݁߹ɾ֎෦݁߹
44. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Content coupling) (Common coupling) (External coupling) ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
45. ੍ޚ݁߹ ʮԿΛ͢Δ͔ʯΛҾ਺ͰܾΊΔ ιϑτ΢ΣΞ։ൃͰ͸ආ͚ΒΕͳ͍ଆ໘΋͋Δ ؇࿨͢΂੍͖ޚ݁߹΋͋Δ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
46. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1 - վળҊ 2 ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
47. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1 - վળҊ 2 ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
48. ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ: ʮΑ͘ͳ͍ʯྫ fun updateView(isError: Boolean) { if (isError) { resultView.isVisible = true errorView.isVisible = false iconView.image = CROSS_MARK_IMAGE } else { resultView.isVisible = false errorView.isVisible = true iconView.image = CHECK_MARK_IMAGE } } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
49. ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ: Կ͕ʮΑ͘ͳ͍ʯ͔ - ಈ࡞Λཧղ͢ΔͨΊʹ͢΂ͯͷ෼ذΛಡΉඞཁ͕͋Δ - ࣮૷ͷมߋʹରͯ͠ؤ݈Ͱ͸ͳ͍ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
50. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ: ૢ࡞ର৅ʹΑΔ෼ׂͷద༻ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1 - վળҊ 2 ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
51. ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ: मਖ਼ํ๏ ৚݅Ͱ͸ͳ͘ɺઌʹૢ࡞ର৅Ͱ෼ׂ͢Δ (લճઆ໌ͨ͠ํ๏) - ੍ޚ݁߹ͷൣғΛখ͘͢͞Δ ৚݅ʹΑͬͯૢ࡞ͷର৅͕มΘΒͳ͍৔߹ʹ༗ޮ - ର৅͕Ұ෦͚ͩҟͳΔ৔߹: updateIf... ౳ͰࠩҟΛٵऩՄ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
52. ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ: मਖ਼ྫ fun updateView(isError: Boolean) { if (isError) { resultView.isVisible = true errorView.isVisible = false iconView.image = CROSS_MARK_IMAGE } else { resultView.isVisible = false errorView.isVisible = true iconView.image = CHECK_MARK_IMAGE } } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
53. ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ: मਖ਼ྫ fun updateView(isError: Boolean) { resultView.isVisible = !isError errorView.isVisible = isError iconView.image = getIconImage(isError) } fun getIconImage(isError: Boolean): Image = if (!isError) CHECK_MARK_IMAGE else CROSS_MARK_IMAGE ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
54. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ: ૢ࡞ର৅ʹΑΔ෼ׂͷద༻ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1 - վળҊ 2 ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
55. ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ: ʮΑ͘ͳ͍ʯྫ 1/2 sealed class DataType { class UserName(...) : DataType() class BirthDate(...) : DataType() class ProfileImage(...) : DataType() } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
56. ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ: ʮΑ͘ͳ͍ʯྫ 2/2 fun updateUserView(dataType: DataType) = when(dataType) { is DataType.UserName -> { val userName = getUserName(dataType.userId) userNameView.text = userName } is DataType.Birthday -> { val birthDate = ... birthDayView.text = format(birthDate, ...) } is DataType.ProfileImage -> { ... } } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
57. ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ: Կ͕ʮΑ͘ͳ͍ʯ͔ - ͢΂ͯͷ෼ذΛಡ·ͳ͍ͱʮԿΛ͢Δ͔ʯ͕Θ͔Βͳ͍ - ݺͼग़͠ݩͷ৚݅ͱݺͼग़͠ઌͷಈ࡞ͷରԠ෇͚͕༰қͰͳ͍ updateUserView(DataType.ProfileImage(...)) fun updateUserView(dataType: DataType) = when(dataType) { is DataType.UserName -> { ... } // Need to check the condition... is DataType.Birthday -> { ... } is DataType.ProfileImage -> { ... } // Finally found ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
58. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ: ૢ࡞ର৅ʹΑΔ෼ׂͷద༻ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1: ৚݅෼ذͦͷ΋ͷͷ࡟আ - վળҊ 2: ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
59. ৚݅෼ذͷ࡟আ ৚݅ຖʹؔ਺Λ෼ׂ͢Δ ݺͼग़͠ݩʹΑͬͯ৚͕݅ ੩తʹ ܾ·Δ৔߹ʹ༗ޮ - ੩తʹ͕ܾ·Βͳ͍৔߹ɺݺͼग़͠ݩͰ੍ޚ݁߹͕ൃੜ͢Δ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
60. ৚݅෼ذͷ࡟আ: ద༻Ͱ͖Δঢ়گྫ ʮݺͼग़͠ݩ͕Ͳ͔͜ʯͰ৚͕ܾ݅·Δ class Caller1 { fun caller1() = presenter.updateUserView(DataType.UserName(...)) } class Caller2 { fun caller2() = presenter.updateUserView(DataType.BirthDate(...)) } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
61. ৚݅෼ذͷ࡟আ: վળྫ fun updateUserView(dataType: DataType) = when(dataType) { is DataType.UserName -> { val userName = getUserName(dataType.userId) userNameView.text = userName } is DataType.Birthday -> { val birthDate = ... birthDayView.text = format(birthDate, ...) } is DataType.ProfileImage -> { ... } } ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
62. ৚݅෼ذͷ࡟আ: վળྫ fun updateUserNameView(...) { val userName = getUserName(...) userNameView.text = userName } fun updateBirthdayView(...) { val birthDate = ... birthDayView.text = format(birthDate, ...) } fun updateProfileImage(...) { ... ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
63. ؇࿨͢΂੍͖ޚ݁߹ - ෆඞཁʹཻ౓ͷେ͖͍৚݅෼ذ - վળҊ: ૢ࡞ର৅ʹΑΔ෼ׂͷద༻ - ಈ࡞ͷؔ࿈ੑ͕ബ͍৚݅෼ذ - վળҊ 1: ৚݅෼ذͦͷ΋ͷͷ࡟আ - վળҊ 2: ଞͷߏ଄Ͱͷஔ͖׵͑ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
64. ଞͷߏ଄Ͱͷஔ͖׵͑ ʮԿΛ͢Δ͔ʯΛܾΊΔΫϥε΍஋Λ࡞Δ ྫ: ετϥςδʔύλʔϯ - ෼ذΛଟ૬ੑ΍ύϥϝʔλͰஔ͖׵͑Δ - ྻڍܕɾந৅ΫϥεɾίʔϧόοΫΦϒδΣΫτ౳Ͱ࣮૷͢Δ - ߏ଄͕ෳࡶʹͳΔͷͰɺଞͷख๏Λ༏ઌ͢Δ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
65. ଞͷߏ଄Ͱͷஔ͖׵͑: վળྫ enum class Binder(val viewId: ViewId) { fun updateView(holder: ViewHolder) = setContent(holder.getView(viewId)) abstract fun setContent(view: View) ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
66. ଞͷߏ଄Ͱͷஔ͖׵͑: վળྫ enum class Binder(val viewId: ViewId) { USER_NAME(USER_NAME_VIEW_ID) { override fun setContent(...) = ... } BIRTHDAY(BIRTHDAY_VIEW_ID) { override fun setContent(...) = ... ... fun updateView(holder: ViewHolder) = setContent(holder.getView(viewId)) abstract fun setContent(view: View) ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
67. ଞͷߏ଄Ͱͷஔ͖׵͑: ஫ҙ఺ ஔ͖׵͑ΔϩδοΫͷൣғΛߟ͑Δ - ൚༻తͳΫϥεʹಛఆػೳͷ࣮૷ΛؚΊͳ͍ - ඞཁͳΒϞσϧͱϩδοΫΛ෼཭͢ΔɾผͷϞσϧΛ༻ҙ͢Δ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
68. ੍ޚ݁߹: ·ͱΊ ෆඞཁʹେ͖͍ɾಈ࡞ͷؔ࿈ͷബ͍৚݅෼ذΛආ͚Δ ੍ޚ݁߹ͷ؇࿨ํ๏ - ૢ࡞ର৅͕ڞ௨: ର৅ʹΑΔ෼ׂͷద༻ - ৚͕݅੩తʹܾ·Δ: ؔ਺ͷ෼ׂʹΑΔ෼ذͷ࡟আ - ͦΕҎ֎: ετϥςδʔύλʔϯ౳ʹΑΔஔ͖׵͑ ґଘؔ܎ > ݁߹౓ > ੍ޚ݁߹
69. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Content coupling) (Common coupling) (External coupling) ґଘؔ܎ > ݁߹౓ > ελϯϓ݁߹
70. ελϯϓ݁߹ Ҿ਺ɾ໭Γ஋Ͱσʔλߏ଄Λड͚౉͢͠Δؔ܎ ࢖Θͳ͍σʔλؚ͕·Ε͍ͯͯ΋ڐ༰͞ΕΔ৔߹΋͋Δ: - ଟ૬ੑΛ࢖͏৔߹΍ετϥςδʔύλʔϯΛ࢖͏৔߹ - Ҿ਺ɾ໭Γ஋Λ୯७Խɾҙຯ෇͚Λ͢Δ৔߹ ґଘؔ܎ > ݁߹౓ > ελϯϓ݁߹
71. ελϯϓ݁߹: ྫ updateUserView(userData) fun updateUserView(userData: UserData) { ґଘؔ܎ > ݁߹౓ > ελϯϓ݁߹
72. ελϯϓ݁߹: ྫ updateUserView(userData) fun updateUserView(userData: UserData) { // Some property of `userData` are used userNameView.text = userData.fullName profileImage.setImageUrl(userData.profileImageUrl) // `userData.mailAddress` and `.phoneNumber` are not used } ґଘؔ܎ > ݁߹౓ > ελϯϓ݁߹
73. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Content coupling) (Common coupling) (External coupling) ґଘؔ܎ > ݁߹౓ > σʔλ݁߹
74. σʔλ݁߹ جຊతͳܕͷΈΛҾ਺ɾ໭Γ஋Ͱड͚౉ؔ͢܎8 fun updateUserView(fullName: String, profileImageUrl: String) { userNameView.text = fullName profileImage.setImageUrl(profileImageUrl) } updateUserView(userData.fullName, userData.profileImageUrl) 8 ݫີʹ͸ɺString ͸จࣈͷ഑ྻ/Ϧετͱߟ͑ΒΕΔ ґଘؔ܎ > ݁߹౓ > σʔλ݁߹
75. σʔλ݁߹: ஫ҙ఺ ελϯϓ݁߹ͷํ͕޷·͍͜͠ͱ΋͋Δ - Ҿ਺ͷҙຯ෇͚͕ඞཁͳ৔߹ - ܕݕࠪΛߦ͑Δ৔߹ fun updateUserView(fullName: String, profileImageUrl: String) = ... updateUserView(imageUrl, fullName) // !!! updateUserView(itemName, itemImageUrl) // !!! updateUserView(userA.fullName, userB.imageUrl) // !!! ґଘؔ܎ > ݁߹౓ > σʔλ݁߹
76. ࠓճͷ಺༰ (Message coupling) (Data coupling) (Stamp coupling) (Control coupling) (Content coupling) (Common coupling) (External coupling) ґଘؔ܎ > ݁߹౓ > ϝοηʔδ݁߹
77. ϝοηʔδ݁߹ ؔ਺ΛҾ਺ɾ໭Γ஋ͳ͠Ͱݺͼग़͚ͩ͢ͷؔ܎ - ႈ౳ͳؔ਺ͷݺͼग़͠౳ ʢྫ: Closable.closeʣ - ผͷ৔ॴͰ಺༰݁߹Λੜ͍ͯ͡ΔՄೳੑ͕͋Δ fun notifyUserDataUpdated() { userNameView.text = ... profileImage.setImageUrl(...) } notifyUserDataUpdated() ґଘؔ܎ > ݁߹౓ > ϝοηʔδ݁߹
78. ݁߹౓: ·ͱΊ ऑ͍݁߹Λ࢖͏ - ελϯϓ݁߹ɾσʔλ݁߹Λҙࣝͯ͠࢖͏ ஫ҙ͢Δ΂͖݁߹ - ಺༰݁߹: ಺෦ͷৄࡉͳಈ࡞ʹґଘ͢Δؔ܎ - ڞ௨݁߹ɾ֎෦݁߹: Մมͳάϩʔόϧσʔλ࢖͏ؔ܎ - ੍ޚ݁߹: ʮԿΛ͢Δ͔ʯΛҾ਺ͰܾΊΔؔ܎ ґଘؔ܎ > ݁߹౓ > ·ͱΊ