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1400万ユーザーのWebサービスを 15年運用して考える、 Javaである理由
masaozi3
May 18, 2019
Technology
1
3.5k
1400万ユーザーのWebサービスを 15年運用して考える、 Javaである理由
masaozi3
May 18, 2019
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Transcript
ϑϦϡʔגࣜձࣾླਅੜ !NBTBP[Jʣ ສϢʔβʔͷ8FCαʔϏεΛ ӡ༻ͯ͠ߟ͑Δɺ +BWBͰ͋Δཧ༝
w ϑϦϡʔגࣜձࣾ!ژ w ࣾձਓྺ+BWBྺ w +BWBͱ4QSJOHͰz(*3-4Λ)"11:ʹz͢ΔࣄΛ͍ͯ͠·͢ w େֶ࣌1ZUIPOͰ8FCΞϓϦΛ։ൃ ͖ͳͷ ษڧձͷελοϑɺϊϕϧςΟͷൃɺ͓͍͍͓͠ञ
ϔΞΧϥʔϒϦʔνɺͷૹঢ়گΛோΊΔ ླਅੜ !NBTBP[J !2 ʘ·͓͞Ͱ͢ʗ w w w
w ࠓͷΰʔϧ w ͷ͖͔͚ͬ w ฐࣾͷαʔϏεͱٕज़બͷ w ʑͷӡ༻͔ΒΈΔ+BWBͰ͋Δཧ༝ w ʲ͓·͚ʳ+%,ͷҠߦͷ
w ݁ w ͓͠Βͤ ࠓ͢͜ͱ !3 ੩͔ʙʹฉ͘ΑΓ ΘʔΘʔݴ͍ͳ͕Β ฉ͍ͯΒ͑Εخ͍͠Ͱ͢ʂ
w ࠓͷΰʔϧ w ͷ͖͔͚ͬ w ฐࣾͷαʔϏεͱٕज़બͷ w ʑͷӡ༻͔ΒΈΔ+BWBͰ͋Δཧ༝ w ʲ͓·͚ʳ+%,ͷҠߦͷ
w ݁ w ͓͠Βͤ ࠓ͢͜ͱ !4 ʮӡ༻ͯ͠ʯͱ͍͍ͭͭ ϲ݄͔͠ݟͯͳ͍ͷͰ ௐͨใ͋Γ·͢
ࠓͷΰʔϧ
!6 ʮ+BWB͕దͨ͠αʔϏεͱԿ͔ʯ ͷҰͭͷղΛݟ͚ͭΔ͜ͱ
ͷ͖͔͚ͬ
w 4DBMB͕େ͖ͳઌഐ͕+BWBΛॻ͍͍ͯͯʑۤͦ͠͏Ͱ͋Δ w पғͷ༑ਓ͕ʮ+BWBઈରॻ͖ͨ͘ͳ͍ʯͳͲݴ͍ͬͯͯɺ ͳΜ͔ͩ൵͍͠ w ͱ͍͑ࣗ+BWB͕͖͘͢͝ͱ͍͏Θ͚Ͱͳ͍ w ྡͷνʔϜαʔόʔαΠυ,PUMJOΛݕ౼͍ͯ͠ΔΑ͏ͩʁ w
ผͷݴޠΛݕ౼ͨ͜͠ͱ͋ΔΒ͍͠ɹɹɹɹɹͳͲͳͲ ͷ͖͔͚ͬ !8
w 4DBMB͕େ͖ͳઌഐ͕ʑۤͦ͠͏Ͱ͋Δ w पғͷ༑ਓ͕ʮ+BWBઈରॻ͖ͨ͘ͳ͍ʯͳͲݴ͍ͬͯͯɺͳΜ͔ͩ൵ ͍͠ w ͱ͍͑ࣗ+BWB͕͖͘͢͝ͱ͍͏Θ͚Ͱͳ͍ w ྡͷνʔϜαʔόαΠυ,PUMJOΛݕ౼͍ͯ͠ΔΑ͏ͩʁ w
ผͷݴޠΛݕ౼ͨ͜͠ͱ͋ΔΒ͍͠ ͷ͖͔͚ͬ !9 ͳΜͰ+BWBΛ͍ͬͯΔΜͩΖ͏ʁ +BWB͕ద͍ͯ͠ΔͷͬͯͳΜͩΖ͏ʁ ଐ͞ΕͨϓϩμΫτ͕+BWB͔ͩͬͨΒ Ҏ֎ͷཧ༝ͳ͍ͷͩΖ͏͔ʁ
w 4DBMB͕େ͖ͳઌഐ͕ʑۤͦ͠͏Ͱ͋Δ w पғͷ༑ਓ͕ʮ+BWBઈରॻ͖ͨ͘ͳ͍ʯͳͲݴ͍ͬͯͯɺͳΜ͔ͩ൵ ͍͠ w ͱ͍͑ࣗ+BWB͕͖͘͢͝ͱ͍͏Θ͚Ͱͳ͍ w ྡͷνʔϜαʔόαΠυ,PUMJOΛݕ౼͍ͯ͠ΔΑ͏ͩʁ w
ผͷݴޠΛݕ౼ͨ͜͠ͱ͋ΔΒ͍͠ ͷ͖͔͚ͬ !10 ⾠ܾͯ͠ϚαΧϦΛ͛ʹདྷͨͷͰͳ͍Ͱ͢ ʮ͏͔Βʹɺྑ͞ΛΓ͍ͨʯ Έͳ͞Μͷ+BWBΛબΜͩཧ༝ +BWBͷ͖ͳͱ͜ΖͳͲͥͻฉ͖͍ͨͰ͢
ฐࣾͷαʔϏεͱ ٕज़બͷ
w ϓϦըऔಘαʔϏε ϓϦϯτγʔϧػͰࡱӨͨ͠ը૾Λ εϚϗΨϥέʔʹμϯϩʔυ͢Δ w ϓϦըΛͬͨ4/4 w ԽহͷϓϨθϯτ w ϓϦᝑମͷޱίϛ
ฐࣾͷαʔϏεϐΫτϦϯΫ !12
w தֶੜʙେֶੜͷ(*3-4͕λʔήοτ ˞(*3-4ʜࣗΛ(*3-4ͱೝ͍ࣝͯ͠Δͯ͢ͷਓ w ձһສਓҎ্ w ଔۀࣜɺϋϩΟϯɺΫϦεϚεͳͲʹ ΞΫηε͕૿͑Δ ฐࣾͷαʔϏεϐΫτϦϯΫ
!13
w Ψϥέʔ͚αΠτΛϦϦʔε αʔόʔͷ࣮+BWB w εϚϗ͚αΠτωΠςΟϒΞϓϦΛϦϦʔε αΠτΞϓϦͷαʔόʔͱʹ+BWB "OESPJEΞϓϦ+BWB w ݱࡏʜ ਓͰӡ༻։ൃத
ฐࣾͷαʔϏεϐΫτϦϯΫ !14
w Ψϥέʔ͚αΠτΛϦϦʔε αʔόʔͷ࣮+BWB w εϚϗ͚αΠτωΠςΟϒΞϓϦΛϦϦʔε αΠτΞϓϦͷαʔόʔͱʹ+BWB "OESPJEΞϓϦ+BWB w ݱࡏʜ ਓͰӡ༻։ൃத
ฐࣾͷαʔϏεϐΫτϦϯΫ !15 ࠓมΘΒͣ+BWB+BWB͍ͯ͠Δʂ
ٕज़બͷ+BWB !16 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ ݟ͕ઌબࢶͷগͳ͞
w ʙࠒ+BWB͕ग़࢝Ίͨ࣌ ιϑτΣΞ։ൃݚڀͷΑ͏ͳͱ͜Ζ +BWBͰԿ͔ࣄۀ͕Ͱ͖ͳ͍͔ͱࡧ ٕज़બͷ !17 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ +BWBͰ Կ͔ʜ
ٕज़બͷ !18 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ w ʙࠒ+BWB͕ग़࢝Ίͨ࣌ +BWBͰԿ͔ࣄۀ͕Ͱ͖ͳ͍͔ͱࡧ w ௨৴ܥϛυϧΣΞ͕
ٕज़બͷ !19 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ Τϯλϝ ͍ͨ͠ͳ w ΤϯλʔςΠϯϝϯτܥͷ͜ͱ͍ͨ͠ʂ ϓϦػͱΨϥέʔͷ௨৴ͱ͔Ͳ͏ͩΖ͏͔
ٕज़બͷ !20 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ w ΤϯλʔςΠϯϝϯτܥͷ͜ͱ͍ͨ͠ʂ w ଞͷݴޠݕ౼ͯ͠Έͨˠબࢶ͕গͳ͍ w "QBDIF5PNDBUͰͭ͘ΔΑ͏ͳͷ 1FSM
"QBDIF "QBDIF 5PNDBU +BWB
ٕज़બͷ !21 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ w ΤϯλʔςΠϯϝϯτܥͷ͜ͱ͍ͨ͠ʂ w ଞͷݴޠݕ౼ͯ͠Έͨˠબࢶ͕গͳ͍ w "QBDIF5PNDBUͰͭ͘ΔΑ͏ͳͷ w
ࣾʹ+BWBͷݟ͕ཷ·͍ͬͯΔͳʜ 1FSM "QBDIF "QBDIF 5PNDBU +BWB
ٕज़બͷ !22 Ψϥέʔ͚αʔϏε͕+BWBͰ͋ͬͨཧ༝ w ΤϯλʔςΠϯϝϯτܥͷ͜ͱ͍ͨ͠ʂ w ଞͷݴޠݕ౼ͯ͠Έͨˠબࢶ͕গͳ͍ w "QBDIF5PNDBUͰͭ͘ΔΑ͏ͳͷ w
ࣾʹ+BWBͷݟ͕ཷ·͍ͬͯΔͳʜ +BWB ݟ͕ઌબࢶͷগͳ͞Ͱ+BWBʹ
ٕज़બͷ !23 ҆ఆͱલαʔϏεɺ+7. εϚϗ͚αʔϏε͕+BWBʹͳͬͨཧ༝
w ʙͷϦϦʔεʹ͚ٕͯज़ݕ౼Λ͢Δ +BWBʹݶΒͣଞͷݴޠϑϨʔϜϫʔΫݕ౼ w ֶशίετ͕Ͳͷ͘Β͍ͳͷ͔ w ϑϨʔϜϫʔΫͷ҆ఆ߹͍ɹɹͳͲͳͲ ٕज़બͷ !24 εϚϗ͚αʔϏε͕+BWBʹͳͬͨཧ༝
4 1MBZ +BWB ʜ 1)1 4DBMB
w ʙͷϦϦʔεʹ͚ٕͯज़ݕ౼Λ͢Δ +BWBʹݶΒͣଞͷݴޠϑϨʔϜϫʔΫݕ౼ w ࣾࢿ࢈׆༻͍ͨ͠ͷͰ+7.ݴޠ͕ྑ͍ Ψϥέʔ͚αʔϏεͰ։ൃͨ͠ϥΠϒϥϦͳͲ ٕज़બͷ !25 εϚϗ͚αʔϏε͕+BWBʹͳͬͨཧ༝ 4
1MBZ +BWB ʜ 1)1 4DBMB
w ʙͷϦϦʔεʹ͚ٕͯज़ݕ౼Λ͢Δ +BWBʹݶΒͣଞͷݴޠϑϨʔϜϫʔΫݕ౼ w ࣾࢿ࢈׆༻͍ͨ͠ͷͰ+7.ݴޠ͕ྑ͍ Ψϥέʔ͚αʔϏεͰ։ൃͨ͠ϥΠϒϥϦͳͲ w 1MBZͱ4DBMBͷΈ߹Θ͕ͤ҆ఆ͍ͯ͠ͳ͍࣌ظ ٕज़બͷ !26
εϚϗ͚αʔϏε͕+BWBʹͳͬͨཧ༝ 4 1MBZ +BWB ʜ 1)1 4DBMB
w ʙͷϦϦʔεʹ͚ٕͯज़ݕ౼Λ͢Δ +BWBʹݶΒͣଞͷݴޠϑϨʔϜϫʔΫݕ౼ w ࣾࢿ࢈׆༻͍ͨ͠ͷͰ+7.ݴޠ͕ྑ͍ Ψϥέʔ͚αʔϏεͰ։ൃͨ͠ϥΠϒϥϦͳͲ w 1MBZͱ4DBMBͷΈ߹Θ͕ͤ҆ఆ͍ͯ͠ͳ͍࣌ظ ٕज़બͷ !27
εϚϗ͚αʔϏε͕+BWBʹͳͬͨཧ༝ 4 1MBZ +BWB ʜ 1)1 4DBMB ҆ఆͱલαʔϏεɺ+7.Ͱ+BWBʹ
w Ψϥέʔ͚αΠτΛϦϦʔε ݟ͕ઌબࢶͷগͳ͔͞Β+BWBʹ w εϚϗ͚αΠτωΠςΟϒΞϓϦΛϦϦʔε ҆ఆͱલαʔϏεɺ+7.͔Β+BWBʹ ٕज़બͷ·ͱΊ !28 ݴޠ༷Ͱͳ͍෦͕ओͳཧ༝
ʑͷӡ༻͔ΒΈΔ +BWBͰ͋Δཧ༝
!30 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ
!31 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ
Ϣʔβʔͷগͳ͍ݴޠϑϨʔϜϫʔΫΛ͍ͬͯͨࠒ w ࣅͨ͜ͱΛ͍ͯ͠Δਓ͕ډͳ͍ w ຊهࣄ͋Μ·Γͳ͍ ࠔ͔ͬͯΒղܾ·Ͱ͕ԕ͔ͬͨ ݴޠͷϢʔβʔ͕ଟ͍ !32 ͍ͬͺ͍ͭΒ͍
Ͱ+BWBͳΒ w ࣅͨ͜ͱΛ͍ͯ͠Δਓ͕ࢁډΔ w ຊهࣄࢁ͋Δ ࠔͬͯௐΕॿ͔Δ͕ߴ͍ ٯʹใʹຒΕͯ͠·͏͜ͱ͋Δ ݴޠͷϢʔβʔ͕ଟ͍ !33 ͭΒ͘ͳ͍ʂ
ϝϯςφϯε͞Ε͍ͯΔͷ͕ଟ͘ɺ͍ଓ͚ΒΕΔ҆৺͕͋Δ w ϥΠϒϥϦɺϑϨʔϜϫʔΫͳͲ w ͏ਓ͕ډΔ͠ɺίϛοτ͢Δਓ͕͍Δ େنͳαʔϏεͱͯ҆͠৺ͯ͑͠Δ͜ͱ͕خ͍͠ ⾠ར༻͢Δ͚ͩͰͳ͘ίϛοτ͍͖ͯ͠·͠ΐ͏ͱ͍͏ ݴޠͷϢʔβʔ͕ଟ͍ !34
ࣾ֎ΘͣਓతϦιʔε͕५Ͱ͋Δ w ଞ෦ॺͱਓΛߦ͖དྷͰ͖Δ w શ͘ҟͳΔΛ࡞Δ෦ॺͱٕज़ަྲྀ͕Ͱ͖Δ ᝒମͷΈࠐΈιϑτΣΞͷνʔϜͳͲ w ࣾ֎ͰਓΛݟ͚͍ͭ͢ w ++6($$$ͱָ͔͍͋ͬͯ͠☺
ݴޠͷϢʔβʔ͕ଟ͍ !35
!36 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ
+BWB੩తܕ͚ݴޠ ɹɹɹίϯύΠϧ࣌ʹܕνΣοΫΛͯ͘͠ΕΔ ྫ͑ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !37
ϥΠϒϥϦଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !38 public interface VegetableService { /** *
ݱࡏͷ०ͷࡊΛฦ͢ * @return */ Vegetable getInSeason(List<Vegetable> vegetables); }
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !39 public class KithenController { @Resource VegetableService
vegetableService; @RequestMapping(path = "/recommend") public ModelAndView recommendMenu() { List<Vegetable> vegetables = refrigeratorService.findVegetables(); Vegetable vegetable = vegetableService.getInSeason(vegetables); //ฦ͖ͬͯͨࡊͰ͓͢͢ΊͷݙཱΛߟ͑Δ… return new ModelAndView("/reccomend.html"); } }
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !40 public class KithenController { @Resource VegetableService
vegetableService; @RequestMapping(path = "/recommend") public ModelAndView recommendMenu() { List<Vegetable> vegetables = refrigeratorService.findVegetables(); Vegetable vegetable = vegetableService.getInSeason(vegetables); //ฦ͖ͬͯͨࡊͰ͓͢͢ΊͷݙཱΛߟ͑Δ… return new ModelAndView("/reccomend.html"); } } ०ͷࡊͬͯ Ұݸ͡Όͳ͍Αͳ
ϥΠϒϥϦଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !41 public interface VegetableService { /** *
ݱࡏͷ०ͷࡊΛฦ͢ * @return */ List<Vegetable> getInSeason(List<Vegetable> vegetables); }
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !42 public class KithenController { @Resource VegetableService
vegetableService; @RequestMapping(path = "/recommend") public ModelAndView recommendMenu() { List<Vegetable> stockVegetables = refrigeratorService.findVegetables(); List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); //ฦ͖ͬͯͨࡊͰ͓͢͢ΊͷݙཱΛߟ͑Δ… return new ModelAndView("/reccomend.html"); } }
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !43 public class KithenController { @Resource VegetableService
vegetableService; @RequestMapping(path = "/recommend") public ModelAndView recommendMenu() { List<Vegetable> stockVegetables = refrigeratorService.findVegetables(); List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); //ฦ͖ͬͯͨࡊͰ͓͢͢ΊͷݙཱΛߟ͑Δ… return new ModelAndView("/reccomend.html"); } } ίϯύΠϧ Τϥʔ
ಉ͘͡ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !44 public class ShoppingController { @Resource VegetableService vegetableService;
@RequestMapping(path = "/market") public ModelAndView market() { List<Vegetable> vegetables = specialPriceService.findVegetables(); Vegetable vegetable = vegetableService.getInSeason(vegetables); //ฦ͖ͬͯͨ०ͷࡊΛͲ͜… return new ModelAndView("/market.html"); } } Θʔ͍͢·ͤΜ ͦͬͪͬͯͨ
ʮ͍͍ͦΕͳ͍ʯʮͦΜͳ͠ΐͬͺ͍ϛεʜʯ ʮͦͦͦΜͳमਖ਼ͷํʜʯ ͱࢥ͍·͕͢ w ٸ͍Ͱमਖ਼͍ͯ͠Δͱ͖ w σʔλΞΫηεʙϓϨθϯςʔγϣϯ·ͰҰؾʹ͔͍͍ͯΔͱ͖ w ϥΠϒϥϦ·ͱΊͯॻ͍ͯΔͱ͖ ͳͲɺҊ֎ͬͯ͠·͏ɻ
੩తܕ͚ͰίϯύΠϥ͕ڧྗ !45
ʜઌఔͷίʔυΛϦϦʔε͔ͯ͠Βϲ݄ޙʜ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !46
ϥΠϒϥϦଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !47 public interface VegetableService { /** *
ݱࡏͷ०ͷࡊΛฦ͢ * @return */ List<Vegetable> getInSeason(List<Vegetable> vegetables); }
ϥΠϒϥϦଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !48 public interface VegetableService { /** *
ݱࡏͷ०ͷࡊΛฦ͢ * @return */ List<Vegetable> getInSeason(List<Vegetable> vegetables) throws NoVegetablesException; } ۭͳΒ ྫ֎ʹͨ͘͠ ͳ͖ͬͯͨ
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !49 List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); try
{ List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); } catch (NoVegetablesException e) { e.printStackTrace(); } ,JUDIFO$POUSPMMFSͱ 4IPQQJOH$POUSPMMFSͰ ͚ͬͯͨͬͳʙ
ར༻ଆͰ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !50 List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); try
{ List<Vegetable> vegetables = vegetableService.getInSeason(stockVegetables); } catch (NoVegetablesException e) { e.printStackTrace(); } ίϯύΠϧ Τϥʔ
ػೳՃ͞Ε͍ͯͨʂ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !51 public class FlyerController { @Resource VegetableService vegetableService;
@RequestMapping(path = "/available") public ModelAndView availableFlyerView() { List<Vegetable> vegetables = specialPriceService.findVegetables(); Vegetable vegetable = vegetableService.getInSeason(vegetables); //ฦ͖ͬͯͨ०ͷࡊΛͲ͜… return new ModelAndView(“/available.html"); } } Θʔ͓ ͦͬͪͬͯͨ
ͪ͜ΒʮͦΜͳ͜ͱ͋Δʁʯͱࢥ͏͔͠Ε·ͤΜ͕ w େ͖ͳ࣮ ϲ݄Ҏ্͔͔ΔͳͲ Λ͍ͯ͠Δͱ͖ w ಉ͡ϓϩμΫτʹରͯͦ͠Μͳ࣮͕ฒߦͰΔঢ়گͷͱ͖ ͳͲΓͬͯ͠·͏໘͕͋Δɻ ੩తܕ͚ͰίϯύΠϥ͕ڧྗ !52
੩తܕ͚ͰίϯύΠϥ͕ڧྗ !53 ࡉ͔͍ϛεಈ͔͢લʹؾ͚ͮΔ΄͏͕ Ұͭͣͭண࣮ʹ࣮ΛਐΊΒΕΔͷͰ ॻ͖͡Ί͔Βྃ·Ͱ͕ૣ͍ ͱ͍͑*%&͕ݡ͘ར༻ՕॴΛ୳ͤͨΓ͢ΔͷͰ ίϯύΠϥΛ௨ͣ͞ͱؾ͚ͮΔͱ͍͏
!54 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ
Ϣʔβʔ͕ສਓ͍Δͱʮكͳҟৗܥʯׂ͕ͱΑ͘ൃੜ͢Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ !55 //΄΅ى͜Γ͑ͳ͍͕… if(hoge.isEmpty()) { return new Collections.emptyList(); }
Ϣʔβʔ͕ສਓ͍Δͱʮكͳҟৗܥʯׂ͕ͱΑ͘ൃੜ͢Δ w ࣮࣌Ͱຊʹك͕ͩͬͨଞͷػೳՃͰى͖͘͢ͳͬͨ w ϦϦʔε͔ͯ͠Β݁ߏك͡Όͳ͍ͳͱൃ֮ɹͳͲͳͲ ྫ֎Λ໌֬ʹॲཧͰ͖Δ !56
Ϣʔβʔ͕ສਓ͍Δͱʮكͳҟৗܥʯׂ͕ͱΑ͘ൃੜ͢Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ !57 //΄΅ى͜Γ͑ͳ͍͕… if(hoge.isEmpty()) { return new Collections.emptyList(); }
ى͜ΔΜ͔ʜ
Ϣʔβʔ͕ສਓ͍Δͱʮكͳҟৗܥʯׂ͕ͱΑ͘ൃੜ͢Δ ͜͏͍͏ಛघέʔεʹରͯ͠ɺ ͕ࣗͨͪѻ͍͍͢ྫ֎Λఆٛͯ͠ॲཧΛଅͤΔͷར ྫ֎Λ໌֬ʹॲཧͰ͖Δ !58 //΄΅ى͜Γ͑ͳ͍͕… if(hoge.isEmpty()) { return
throw new HogeIsEmptyException(); } ྫ֎ʹͨͬͨ͠ ΄͏͕͍ͳ
!59 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ
!60 ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ Ћ
ศརͳͷ͕ࢁ͋Γɺ։ൃεϐʔυ͕ૣ͍ w *%&͕ڧྗ ϦϑΝΫλϦϯάҰͭͰݡ͍ػೳ͕උΘ͍ͬͯΔͷ͕͋Δ ิ͕ڧྗɺ$POWFSU5P,PUMJOͱ͔·Ͱ͋Δ ॻ͘εϐʔυ͕ૣ͘ͳΔ w ඪ४ϥΠϒϥϦ͕ॆ࣮͍ͯ͠Δ ϥΠϒϥϦΛ୳͕࣌ؒ͢ݮΔͷͰ࣮ʹूதͰ͖Δ ʲ
Ћʳ ։ൃڥ͕ڧྗͳ !61
ศརͳͷ͕ࢁ͋Γɺ։ൃεϐʔυ͕ૣ͍ ॳ৺ऀͰʮ·ͣಈ͘ͷʯ͕ग़དྷ্͕Δ·Ͱ͕ૣ͍ w ࠔͬͨˠͰָ͖͍͕ͨ͠ૣ͍ w ࣗ৴ͱ͔Ϟνϕʔγϣϯʹ݁͢Δ ʲ Ћʳ ։ൃڥ͕ڧྗͳ !62
ʲ͓·͚ʳ +%,ͷҠߦͷ
w ϐΫτϦϯΫͰ0SBDMF+%,Λ͍ͬͯͨ +%,ͷҠߦ !64 0SBDMF +%,ʙ̇
w ϐΫτϦϯΫͰ0SBDMF+%,Λ͍ͬͯͨ w 0SBDMFͷαϙʔτϙϦγʔ͕มΘͬͨ ࣮ӡ༻Ͱ͑Δ+%,݄·Ͱ Ҿ͖ଓ͖͏ʹܖ͕ඞཁ ͦΕؒͰαϙʔτऴྃͷ༧ఆ +%,Ҏ߱ಉ͘͡ܖ͕ඞཁ w Կ͔͠ΒରԠΛ͠ͳͯ͘ͳΒͳ͍ঢ়گ
+%,ͷҠߦ !65 αϙʔτ ऴΘΔΑʂ
ߟ͑ΒΕΔબࢶ͍͔ͭ͘ w 0SBDMF+%,Ͱܖ͢Δ w 0SBDMF+%,Ͱܖ͢Δ w ֤ࣾஂମͷ+%,ʹҠߦ͢Δ w ͍ͬͦଞͷݴޠʹͯ͠͠·͏ +%,ͷҠߦ
!66
ߟ͑ΒΕΔબࢶ͍͔ͭ͘ w 0SBDMF+%,Ͱܖ͢Δ w 0SBDMF+%,Ͱܖ͢Δ w ֤ࣾஂମͷ+%,ʹҠߦ͢Δ w ͍ͬͦଞͷݴޠʹͯ͠͠·͏ +%,ͷҠߦ
!67 ͙͢ʹରԠ͢Δͷ͍͠ ͙͢ʹରԠ͢Δͷ͍͠ ͳ͔ͳ͔ͷֹۚʹͳΓͦ͏ʜ ͳ͔ͳ͔ͷֹۚʹͳΓͦ͏ʜ
w ͻͱ·ͣ"EPQU0QFO+%,ʹҠߦ͢Δ͜ͱʹ w खॱʹಛผͳ͜ͱͳ͍ w ΞϓϦέʔγϣϯ͔Β"EPQU0QFO+%,Λࢀর͢ΔΑ͏ʹ͢Δ w ςετڥͰϏϧυɺϢχοτςετ͕௨Δ͔νΣοΫ w ϲ݄΄Ͳςεταʔόʔʹஔ͍ͯΞϓϦέʔγϣϯΛ৮Γ͓ͨ͢
w όάΈ͋ͨΒͳ͚ΕϦϦʔε +%,ͷҠߦ !68 ࠓίί
ࠓޙ w վΊͯͲͷ+%,ʹ͢Δͷ͔ w +BWBͷόʔδϣϯͲ͏͢Δͷ͔ ͳͲΛݕ౼ͯͬͯ͠ରԠΛ͍ͯ͘͠༧ఆ +%,ͷҠߦ !69
ͱɺ͞Βͬͱ͕͓ΘΓ·͕ͨ͠ +%,ͷҠߦ !70
w ରԠ͢ΔதͰɺ+BWBࣗମʹର͢ΔࠔΓ͝ͱಛʹແ͔ͬͨ w ਓͰ·ͳͯ͘ɺੈքதͷਓͷҙݟ͕ಘΒΕΔ w 0SBDMFҎ֎ʹ+%,ͷఏڙऀ͕͍Δ w ݟ͔ͭͬͨ՝ࣾͷ͔Γ w ৽͍͠όʔδϣϯʹ͙͢ʹରԠͰ͖ͳ͍ঢ়گΞʔΩςΫνϟ
+%,ͷҠߦ !71
݁
ྺ࢙తܦҢ ࣾʹઌʹݟ͕͋ͬͨɺଞͷબࢶͷͳ͞ ݴޠͷϢʔβʔ͕ଟ͍ ੩తܕ͚ͰίϯύΠϥ͕ڧྗͰ͋Δ ྫ֎Λ໌֬ʹॲཧͰ͖Δ ϐΫτϦϯΫ͕+BWBͰ͋Δཧ༝
!73
!74 ʮ+BWB͕దͨ͠αʔϏεͱԿ͔ʯ
!75 w Ϣʔβʔ͕ଟ͘ɺن͕େ͖͍αʔϏε w ίϛοτ͢Δϝϯόʔ͕มԽ͍͢͠ɺ ͍ͭ୭͕Ͳ͜Λ৮Δ͔ಡΊͳ͍αʔϏε
!76 w Ϣʔβʔ͕ଟ͘ɺن͕େ͖͍αʔϏε w ίϛοτ͢Δϝϯόʔ͕มԽ͍͢͠ɺ ͍ͭ୭͕Ͳ͜Λ৮Δ͔ಡΊͳ͍αʔϏε Έͳ͞Μͷ͝ҙݟ ͥͻฉ͖͍ͨͰ͢ʂ
!77 ϐΫτϦϯΫ+BWBͰΑ͔ͬͨʁ
!78 :&4
w ୭͕Ͳ͜Λ͍ͭ৮Δ͔Θ͔Βͳ͍ঢ়ଶ গͳ͘ͱνʔϜίʔυΛ৮ΔڪΕ͕͋ΔϓϩμΫτ ͪΐͪ͜ΐ͜ଞ෦͔Βਓ͕དྷͨΓνʔϜฤ͕มΘͬͨΓ͢Δ ͳͷͰ w ੩తܕ͚Ͱ͋Δ͜ͱͰࣗͷΒͳ͍ͱ͜ΖͳΔ҆͘શʹ͍͢͠ w ଞ෦ॺ+BWBྺͷ͋Δਓ͕ଟ͍ͷͰߦ͖དྷ͍͢͠ ϐΫτϦϯΫ͕+BWBͰ͋Δཧ༝
!79
w Ϣʔβ͕ສਓ͍ΔͰ͔͍αʔϏεͰ͋Δ ίϯύΠϧஈ֊Ͱ͔ͬ͠ΓνΣοΫͨ͠ͷΛੈʹग़ͤΔͷ͍ͩ͡ ϥΠϒϥϦͳͲϝϯς͞ΕͯΔͷ͕͔ͭ͑Δͷخ͍͠ ҆શͳαʔϏεΛఏڙ͍͢͠ w ίʔυͷϘϦϡʔϜɺաڈͷࢿ࢈͔ͳΓͰ͔͍ աڈͷࢿ࢈ͱ͍͏ҙຯͰ+7.ݴޠͰ͋Ε׆༻Ͱ͖Δ ϐΫτϦϯΫ͕+BWBͰ͋Δཧ༝ !80
͓͠Βͤ
͓Βͤͦͷ̍ !82 Ұॹʹಇ͘ϝϯόʔΛืूதͰ͢ɻ ΤϯδχΞืूதʂ
͓Βͤͦͷ̍ !83 w ژӺɹెา w ΧϯϑΝϨϯεࣾඅͰʂ ަ௨අ॓ധඅࢀՃඅ͓څྉग़·͢ w ࣾͰͷษڧձ͍Ζ͍Ζ w
ৄͪ͘͜͠Β ΤϯδχΞืूதʂ
͓Βͤͦͷ !84 ژ%FW͔;͐ w ژӺલʙ w ςʔϚ৭ʑ w ίʔώʔɺ࠙ձ͖ w
ৄ͘͠DPOOQBTTͰʂ ษڧձͬͯΔͷͰདྷ͍ͯͩ͘͞ʂ
͓Βͤͦͷ !85 ొஃऀืूதͰ͢ʂ $G1ग़͔ͨͬͨ͠3FKFDUͩͬͨ ͕ࣗΈͨηογϣϯ·ͱΊ ͳͲͳͲͳΜͰ͟͝Εʂ
ສϢʔβʔͷ8FCαʔϏεΛ ӡ༻ͯ͠ߟ͑Δɺ+BWBͰ͋Δཧ༝ ϑϦϡʔגࣜձࣾླਅੜ !NBTBP[Jʣ ͝ਗ਼ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠ʂ