オブジェクト指向のこころを学んだ話

社内LT用資料
参考資料リンク:
https://www.maruzen-publishing.co.jp/item/b294729.html
https://jp.quora.com/%E3%82%AA%E3%83%96%E3%82%B8%E3%82%A7%E3%82%AF%E3%83%88%E6%8C%87%E5%90%91%E3%81%A8%E3%81%AF%E4%BD%95%E3%81%A7%E3%81%99%E3%81%8B
https://www.ogis-ri.co.jp/otc/hiroba/technical/MPD/
https://github.com/tofu511/til/tree/master/books/%E3%82%AA%E3%83%96%E3%82%B8%E3%82%A7%E3%82%AF%E3%83%88%E6%8C%87%E5%90%91%E3%81%AE%E3%81%93%E3%81%93%E3%82%8D

Transcript

1. ΦϒδΣΫτࢦ޲ͷ͜͜ΖΛ ֶΜͩ࿩ @tofu511 2020/11/26
2. લஔ͖ ͜͜࠷ۙΦϒδΣΫτࢦ޲΍ؔ࿈͢ ΔྖҬʹؔ৺͕͋Γɺˡͷຊ͕ͱͯ ΋ྑ͔ͬͨͷͰֶͼΛΞ΢τϓοτ ͢ΔLTΛ࡞Γ·ͨ͠ɻ શͯ͸঺հ͖͠Εͳ͍ͷͰؾʹͳΔ ํ͸ങͬͯಡΜͰ͍ͩ͘͞
3. ஫ҙࣄ߲ ݸਓͷཧղͷͨΊෆਖ਼֬ͳ෦෼͕͋Δ ͔΋͠Ε·ͤΜ
4. ໨࣍ • લఏͱͯ͠ͷίϯςΩετ੔ཧ • ΦϒδΣΫτࢦ޲ҎલͷύϥμΠϜ • ΦϒδΣΫτࢦ޲ͷύϥμΠϜ • σβΠϯύλʔϯͱChristopher Alexander • ڞ௨ੑ/Մมੑ෼ੳ • BridgeύλʔϯͰཧղ͢Δ • ࢀߟࢿྉ
5. લఏͱͯ͠ͷίϯςΩετ੔ཧ
6. ΦϒδΣΫτࢦ޲ʹ͋Δ2ͭͷΞΠσΞ • ʮΦϒδΣΫτʯͱʮΫϥεʯͱ͍͏ΞΠσΞ͸1967೥ʹSimula67ͱ ͍͏ϓϩάϥϛϯάݴޠʹΑͬͯొ৔ͨ͠ • ʮΦϒδΣΫτʯͱʮΫϥεʯΛԠ༻ͯ͠2ͭͷΞΠσΞ͕ఏҊ͞Εͨ • 1:ʮϝοηʔδϯάʢϝοηʔδૹ৴ʣʹΑΔܾఆͷ஗Ԇͷపఈʯ • 2:ʮΫϥεʹΑΔந৅σʔλܕͷ࣮ݱʢΧϓηϧԽɾܧঝɾଟଶ ੑʣʯ
7. ࠓճѻ͏ͷ͸2ͷํͰ͢
8. ΦϒδΣΫτࢦ޲ҎલͷύϥμΠϜ: ಋೖ • ΦϒδΣΫτࢦ޲ͷύϥμΠϜΛઆ໌͢ΔͨΊʹҰൠతͳߏ଄Խϓϩ άϥϛϯάΛऔΓ্͛·͢ • ͦ΋ͦ΋ΦϒδΣΫτࢦ޲ͷύϥμΠϜ͸ߏ଄Խϓϩάϥϛϯάͷܽ ఺Λิ׬͢ΔͨΊʹੜ·Ε͖ͯͨ(ৄࡉ͸WikiͰ)
9. ΦϒδΣΫτࢦ޲ҎલͷύϥμΠϜ:ػೳ෼ղ • σʔλϕʔε͔Β঎඼ͷϦετΛදࣔ͢ΔϓϩάϥϜ͕͋Δͱ͠·͢ • ΍Δ΂͖खॱΛચ͍ग़͠ฒ΂Δ 1. σʔλϕʔεʹ͋Δ঎඼Λݕࡧ͢Δ 2. ঎඼ϦετΛऔಘ͢Δ 3. ϦετΛԿ͔͠ΒͷϧʔϧͰฒ΂Δ 4. ը໘্ʹ঎඼ΛͦΕͧΕදࣔ͢Δ • ͜ͷΑ͏ʹ໰୊Λখ͞ͳػೳʹϒϨʔΫμ΢ϯͯ͠໰୊Λߏ੒͢ΔػೳΛચ͍ग़͢ ख๏͜ͱΛػೳ෼ղͱݺͿ
10. ΦϒδΣΫτࢦ޲ҎલͷύϥμΠϜ:ػೳ෼ղ • ػೳ෼ղʹ͸෼ׂͨ͠ػೳΛਖ਼͍͠ॱংͰݺͼग़͢ϝΠϯϓϩάϥϜ ͕ඞཁͱͳΔେ͖ͳམͱ͕݀͋͠Δ • ϝΠϯϓϩάϥϜ͕શͯͷػೳΛਖ਼͘͠ݺͼग़͢੹຿͕͋ΔͷͰɺ ιʔείʔυ͕ෳࡶԽ͠΍͘͢ͳΔ
11. ΦϒδΣΫτࢦ޲ҎલͷύϥμΠϜ:มԽ΁ͷରԠ • ػೳ෼ղΞϓϩʔνͰมԽʹରԠ͢Δ৔߹ɺ௿ڽूɾີ݁߹ͱ͍͏ผ ͷ໰୊΋ൃੜ͢Δ
12. ΦϒδΣΫτࢦ޲Ҏલͷ ύϥμΠϜ:มԽ΁ͷରԠ // ScalaͬΆ͍ٙࣅίʔυ object Main extends App { val product = getProductFromDatabase() product match { case Book => // දࣔϩδοΫ case Food => // do something // छྨ͕૿͑ͨΒ͜͜Λม͑ͳ͍ͱ ͍͚ͳ͍ } def getProductFromDatabase() = ??? //DB͔Β঎඼Λऔಘ͢Δ def displayProduct(product: Any) = ??? //දࣔ͢Δ } • ػೳ෼ղΞϓϩʔνͰมԽʹରԠ͢Δ৔߹ɺ௿ڽूɾີ݁߹ʹ ΑΔฐ֐ͱ͍͏ผͷ໰୊΋ൃੜ͢Δ • ӈ͸঎඼ΛDB͔Βऔಘ͠දࣔ͢Δ(ۃ୺ͳ)ྫ • ಛఆͷຊ΍৯඼Ͱ͸ผͷॲཧʹ͍ͨ͠ͱ͖ͲΜͲΜෳࡶʹͳͬ ͯ͠·͏
13. ΦϒδΣΫτࢦ޲ͷύϥμΠϜ • ΦϒδΣΫτࢦ޲ͷύϥμΠϜͰ͸໰୊ྖҬΛػೳͰ͸ͳ͘ΦϒδΣ Ϋτʹ෼ղ͍ͯ͘͠ • ΦϒδΣΫτ͸ͦΕ͕ෛ͏੹೚Λ΋ͱʹચ͍ग़͢ • Martin Fowlerͷ؍఺Ͱ͸ΦϒδΣΫτʹ͸3ͭͷϨϕϧͷ؍఺͕ଘࡏ ͢Δ
14. ΦϒδΣΫτࢦ޲ͷύϥμΠϜ:Fowlerͷ؍఺ • ֓೦Ϩϕϧ • ιϑτ΢ΣΞͱؔ܎ͳ͘ಋ͖ग़͞ΕΔ΋ͷ • ʮࢲ͸Կʹରͯ͠੹೚͕͋Δͷ͔ʁʯͱ͍͏࣭໰Λ౴͑Δ΋ͷ • ֓೦Ϩϕϧʹ͓͍ͯΦϒδΣΫτ͸੹೚ͷू߹ͱͳΔ
15. ΦϒδΣΫτࢦ޲ͷύϥμΠϜ:Fowlerͷ؍఺ • ࢓༷Ϩϕϧ • ιϑτ΢ΣΞͷΠϯλʔϑΣʔε • ʮࢲ͸ͲͷΑ͏ʹ࢖༻͞ΕΔ͔ʁʯͱ͍͏࣭໰ʹ౴͑Δ΋ͷ • ࢓༷Ϩϕϧʹ͓͍ͯɺΦϒδΣΫτ͸ͦͷଞͷΦϒδΣΫτ΍ࣗΒ Λىಈ͢Δ͜ͱ͕Ͱ͖Δϝιου(ৼΔ෣͍)ͷू߹ͱͳΔ
16. ΦϒδΣΫτࢦ޲ͷύϥμΠϜ:Fowlerͷ؍఺ • ࣮૷Ϩϕϧ • ιʔείʔυ • ʮࢲ͸ͲͷΑ͏ʹͯࣗ͠਎ͷ੹೚Λશ͏͢Δͷ͔ʁʯͱ͍͏࣭໰ʹ ౴͑Δ΋ͷ • ࣮૷Ϩϕϧʹ͓͍ͯɺΦϒδΣΫτ͸ίʔυͱσʔλɺ·ͨͦΕΒ ͷԋࢉॲཧ
17. ΦϒδΣΫτࢦ޲ͷ ύϥμΠϜ // ScalaͬΆ͍ٙࣅίʔυ trait Product { def display() = ??? // ঎඼Λදࣔ͢Δ } case class Book extends Product { // Bookݻ༗ͷॲཧΛҕৡ override def display() = ??? } case class Food extends Product { // Foodݻ༗ͷॲཧΛҕৡ override def display() = ??? } class ProductDatabase { def getProductFromDatabase(): Product = ??? //DB͔Β঎඼Λऔಘ͢Δ } object Main extends App { val product = new ProductDatabase().getProductsFromDataba se() product.display() } • ઌ΄Ͳͷ঎඼Λදࣔ͢ΔྫΛΦϒδΣΫτʹ෼ղ͠ ͯΈͨྫ • ந৅ΫϥεʹΑͬͯಉ֓͡೦Λแؚ͠ɺެ։Πϯ λʔϑΣʔεΛ௨ͯ͡ॲཧΛݺͼग़͢ • ΦϒδΣΫτݻ༗ͷॲཧ͸ϙϦϞʔϑΟζϜʹΑͬ ͯͦΕͧΕͷΦϒδΣΫτͷ੹຿ͱ࣮ͯ͠ߦ͞ΕΔ
18. σβΠϯύλʔϯͱChristopher Alexander • σβΠϯύλʔϯΛ௨ֶͯ͡Ϳ͜ͱͰΦϒδΣΫτࢦ޲ύϥμΠϜ͕ ΑΓཧղͰ͖Δ(ΦϒδΣΫτࢦ޲ͷ͜͜ΖͷϝΠϯτϐοΫ) • σβΠϯύλʔϯͷഎޙʹ͸ݐஙֶɾจԽਓྨֶͱChristopher Alexanderͷύλʔϯͷ఩ֶ͕͋Δ • Christopher Alexanderͱ͍͏ݐஙՈ͸ʮ඼࣭͸٬؍తͳ΋ͷ͔ʁʯ ͱ͍͏ٙ໰Λ๊͍ͨ
19. σβΠϯύλʔϯͱChristopher Alexander • Alexander͸༏Εͨ඼࣭Λอ͍ͬͯΔ΋ͷ͸ߏ଄͸ҟͳ͍ͬͯͯ΋ಉ ͡໰୊Λղܾ͍ͯ͠Δͱ͍͏ڞ௨఺Λݟ͚ͭͨ • ྫ: ܗ͕ҧ͏ϙʔνͰ΋༏Εͨϙʔν͸௨࿏ͱυΞΛܨ͙ͱ͍͏ಉ ͡໰୊Λղܾ͍ͯ͠Δ • Alexander͸ɺΑ͘ࣅͨ໰୊Λղܾ͢Δߏ଄ʹண໨͠ɺ༏Εͨઃܭʹ ଘࡏ͢Δྨࣅ఺Λચ͍ग़͠ɺͦͷྨࣅ఺ΛύλʔϯͱݺΜͩ
20. σβΠϯύλʔϯͱChristopher Alexander • 1990೥୅ॳ಄ɺAlexanderͷ੒ՌΛιϑτ΢ΣΞͷઃܭʹ࢖༻͠ɺग़དྷ্͕ͬͨ΋ͷ͕σβΠϯύ λʔϯ • GoFͷσβΠϯύλʔϯͳͲ • GoFͷ Design Patterns: Elements of Reusable Object-Oriented Software Ͱ͸ΦϒδΣΫτࢦ޲Λલ ఏͱͯ͠ύλʔϯʹج͍ͮͨΞϓϩʔνΛߦͳ͍ͬͯΔ • GoF͸༏ΕͨΦϒδΣΫτࢦ޲ઃܭΛੜΈग़ͨ͢ΊͷઓུΛ͍ࣔࠦͯ͠Δ • ΠϯλʔϑΣʔεΛ༻͍ͯઃܭ͢Δ • ΫϥεܧঝΑΓ΋ΦϒδΣΫτͷू໿Λଟ༻͢Δ • ྲྀಈతཁૉΛݟ͚ͭग़͠ΧϓηϧԽ͢Δ
21. ڞ௨ੑ/Մมੑ෼ੳ • GoFͷ Design Patterns: Elements of Reusable Object-Oriented Softwareʹ͸ҎԼͷΑ͏ʹड़΂ΒΕ͍ͯΔ • ઃܭมߋΛڧ͍ΔՄೳੑͷ͋Δ΋ͷ͕Կ͔Λߟ͑ΔͷͰ͸ͳ͘ɺ࠶ ઃܭΛͤͣʹԿΛมߋՄೳʹ͢Δͷ͔Λߟ͑ΔͷͰ͢ɻ͜͜Ͱண໨ ͍ͯ͠Δͷ͸ɺྲྀಈత֓೦ͷΧϓηϧԽͰ͋Γɺଟ͘ͷσβΠϯύ λʔϯͷςʔϚͱ΋ͳ͍ͬͯΔ΋ͷͰ͢
22. ڞ௨ੑ/Մมੑ෼ੳ • Կ͕ྲྀಈతཁૉͰͲͷΑ͏ʹมԽ͢Δ͔Λࣝผ͢ΔͨΊʹ࢖༻Ͱ͖Δͷ͕ڞ௨ੑ/ Մมੑ෼ੳ • James Coplienࢯ͕ఏএ • ڞ௨ੑͱ͸ʮશͯͷϑΝϛϦߏ੒һʹڞ௨͢Δੑ࣭ʯͷ͜ͱ • ϑΝϛϦߏ੒һͱ͸͋Δঢ়گ΍࣮ߦػೳʹݱΕΔޓ͍ʹؔ࿈ͷ͋Δཁૉͷ͜ͱ • Մมੑͱ͸ʮϑΝϛϦߏ੒һ͝ͱʹҟͳΔੑ࣭ʯͰՄมੑΛԿΒ͔ͷܗͰύϥ ϝʔλԽͰ͖Δͱ࠶ར༻ੑ͕૿͢
23. ڞ௨ੑ/Մมੑ෼ੳ • ྫ͑͹ɺϗϫΠτϘʔυϚʔΧʔɾԖචɾϘʔϧϖϯ͕͋Δͱ͢Δ • ͜ΕΒͷڞ௨ੑ͸ʮචه༻۩ʯͰ͋Δͱ͍͏͜ͱ • චه༻۩͝ͱͷҧ͍ʢࡐ࣭ɾܗঢ়ͳͲʣ͸ՄมੑʹͳΔ • ڞ௨ੑ/Մมੑ෼ੳ͔ΒFowlerͷ3ͭͷ؍఺Λ௨ͯ͡ൃݟ͞ΕͨΦϒδΣΫτ͸ Α͋͘Δʮ໰୊ྖҬʹ͋Δ໊ࢺΛΦϒδΣΫτʹ͠ɺಈࢺΛϝιουʹ͢Δʯ ͱ͍͏ΞϓϩʔνΑΓ༏ΕͨΞϓϩʔνʹͳΔͦ͏Ͱ͢ • චऀᐌ͘Α͋͘ΔΞϓϩʔνͩͱඞཁҎ্ʹਂ͍Ϋϥε֊૚͕࡞ΒΕͯ͠· ͍͕ͪͩͱͷ͜ͱ
24. ڞ௨ੑ෼ੳ Մมੑ෼ੳ ֓೦্ͷ؍఺ ࢓্༷ͷ؍఺ ࣮૷্ͷ؍఺ ந৅Ϋϥε ۩৅Ϋϥε ۩৅Ϋϥε ܧঝ
25. BridgeύλʔϯͰཧղ͢Δ • ྲྀಈతཁૉΛΧϓηϧԽ͢Δྫͱͯ͠BridgeύλʔϯΛऔΓ্͛·͢
26. Bridgeύλʔϯͷ伴ͱͳΔಛ௃ • ໨త • ࣮૷Λ࢖༻͍ͯ͠ΔΦϒδΣΫτ܈͔ΒɺͦͷҰ࿈ͷ࣮૷Λ੾Γ཭͢ • ໰୊ • Ϋϥε਺ͷരൃΛট͘͜ͱͳ͘ɺந৅Ϋϥεͷ೿ੜ෺͔Βෳ਺ͷ࣮૷Λ࢖༻͢ Δඞཁ͕͋Δ • ղܾࡦ • ࢖༻͢Δશͯͷ࣮૷ͷΠϯλʔϑΣʔεΛఆٛ͠ɺந৅Ϋϥεͷ೿ੜ෺͔Βͦ ΕΒΛ࢖༻͢Δ
27. BridgeύλʔϯͰཧղ͢Δ
28. BridgeύλʔϯͰཧղ͢Δ • ͋Δܗঢ়Λඳը͢ΔγεςϜΛߟ͑Δ • ܗঢ়ͷछྨͱඳըํ๏͕ྲྀಈతཁૉʹͳΔ • ࢛֯ΛඳըɺؙΛඳը…ͳͲ • ඳըํ๏ʹ΋ෳ਺ͷVersion͕͋Δ • ܧঝΛ࢖ͬͨΞϓϩʔνͩͱܗঢ়΍ඳըํ๏͕૿͑Δͨͼʹ૊Έ߹Θ ͤ(Ϋϥε਺)͕ࢦ਺తʹ૿͑ͯ͠·͏
29. BridgeύλʔϯͰཧղ͢Δ
30. BridgeύλʔϯͰཧղ͢Δ • BridgeύλʔϯͰ͸ɺܗঢ়ͷந৅తଆ໘(ShapeΫϥεͷந৅తଆ໘) ͱඳըͷ࣮૷(Drawingͷ࣮૷)Λ੾Γ཭͢ • ࣮૷ΛΦϒδΣΫτ͔Β࢖༻͢Δ΋ͷͱ͍͏؍఺ʹཱͭ͜ͱͰɺ࣮૷ ʹ͓͚ΔྲྀಈతཁૉΛӅṭ͢Δ • ྲྀಈతཁૉΛݟ͚ͭग़͠ɺͦΕΛΧϓηϧԽ͢Δ • ΫϥεܧঝͰ͸ͳ͘ͷू໿Λଟ༻͢Δ
31. BridgeύλʔϯͰཧղ͢Δ ܗঢ়ͷ ந৅తଆ໘ ඳըͷ࣮૷
32. ίʔυαϯϓϧ // Scalaͷίʔυྫ trait Shape { val drawing: Drawing def draw(): Unit } class Rectangle(override val drawing: Drawing) extends Shape { override def draw(): Unit = drawing.drawLine() } class Circle(override val drawing: Drawing) extends Shape { override def draw(): Unit = drawing.drawCircle() } trait Drawing { // ࣮ࡍ͸ඳըͷͨΊʹඞཁͳҾ਺ΛऔΔ def drawLine(): Unit def drawCircle(): Unit } class V1Drawing extends Drawing { override def drawLine(): Unit = println("V1 drawLine") override def drawCircle(): Unit = println("V1 drawCircle") } class V2Drawing extends Drawing { override def drawLine(): Unit = println("V2 drawLine") override def drawCircle(): Unit = println("V2 drawCircle") } object Client { def main(args: Array[String]): Unit = { val shapes = Seq( new Rectangle(new V1Drawing()), new Rectangle(new V2Drawing()), new Circle(new V1Drawing()), new Circle(new V2Drawing()) ) shapes.foreach(_.draw()) } }
33. ·ͱΊ • ΦϒδΣΫτࢦ޲Ͱ͸੹೚ΛݩʹΦϒδΣΫτΛ෼͚͍ͯ͘ • ΦϒδΣΫτʹ͸ந৅౓ͷҟͳΔ3ͭͷ؍఺͕͋Δ • σβΠϯύλʔϯ͸Alexanderͷ੒Ռʹେ͖͘Өڹ͞Ε͓ͯΓɺΦϒδΣ Ϋτࢦ޲ΛֶͿ্Ͱͷྑ͍ڭࡐʹͳΔ • ΦϒδΣΫτࢦ޲ઃܭʹ͓͍ͯɺڞ௨ੑ/Մมੑ෼ੳ͔ΒΦϒδΣΫτͷڞ ௨ੑͱՄมੑΛ୳͠ɺ3ͭͷ؍఺ΛݩʹΦϒδΣΫτΛ෼ׂ͢Δ͜ͱͰΦ ϒδΣΫτࢦ޲Β͍͠ઃܭͱͳΔ
34. ͓·͚ • ຊͷ಺༰͸ੲ ಡॻϝϞ Λ࡞ͬͨͷͰͬ͘͟Γ஌Γ͍ͨํ͸ͪ͜ΒΛ Ͳ͏ͧ
35. ࢀߟࢿྉ • σβΠϯύλʔϯ ͱͱ΋ʹֶͿ ΦϒδΣΫτࢦ޲ͷ͜͜Ζ • ΦϒδΣΫτࢦ޲ͱ͸ԿͰ͔͢ʁ • ϚϧνύϥμΠϜσβΠϯɹ- ং࿦ - • ಡॻϝϞ