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渋谷Java #3
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mystelynx
September 28, 2013
Programming
2
270
渋谷Java #3
guava totallylazy java8
について
mystelynx
September 28, 2013
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Transcript
Java8ɺͪΐͬͱͦͷલʹ ौ୩Java #3 Urakawa Tomohiro / @mystelynx 139݄28༵
ࣗݾհ Urakawa Tomohiro @mystelynx ؋ୂ࢘ྩ෦Level.19 ΫοΩʔ͞Μଔۀ͠·ͨ͠ɻ גࣜձࣾALBERTɹγεςϜ։ൃ෦ ࠷ۙRedshiftͱٔΕ͍ͯ·͢ɻ 139݄28༵
Agenda JavaͰ͑ΔؔܕϥΠϒϥϦ guava-libraries totallylazy ͦΕͧΕͷ༻্ͷҙɾ༻๏ʗ༻ྔͳͲ Java8ͱซ༻͢Δͱʁ 139݄28༵
139݄28༵
guava-libraries https:/ /code.google.com/p/guava-libraries/ ࠷৽όʔδϣϯɿ15.0 (2013/09/06) υΩϡϝϯτ͕݁ߏࡉ͔͘ॻ͔Ε͍ͯΔ ศརͳCollectionUtilitiesͳͲؚΜͰ͍Δ ࠓճؔܕϓϩάϥϛϯάػೳʹ 139݄28༵
ίʔυྫ̍ ݁ߏͬͨΒ͍͠ʢओ؍ 139݄28༵
ίʔυྫ̎ ͔ͦ͜ͱͳ͘υϠײΛײ͡Δʢओ؍ 139݄28༵
ॴײ CharMatcherͳͲᙱ͍ͱ͜Ζʹख͕ಧ͘ ແବʹ࣮͠ͳ͍ͨΊʹɺԿ͕༻ҙ͞Ε ͯΔ͔େମѲ͓ͯ͜͠͏ શମతʹΫϥεʗϝιου໊ΛۃྗΘ͔Γ ͘͢͠Α͏ͱͯ͘͠Ε͍ͯΔײ͕͋Δɻ ٯʹ͔Γʹ͍͘ʁʢmapͩΖ…ͱ͔ʣ 139݄28༵
ҙ Java8ͷඪ४ϥΠϒϥϦͱΫϥε໊͕ඃΔ java.util.function.Function vs com.google.common.base.Function java.util.function.Predicate vs com.google.common.base.Predicate ඍົʹϝιου໊͕׳Εͳ͍ 139݄28༵
139݄28༵
totallylazy https:/ /code.google.com/p/totallylazy/ ࠷৽όʔδϣϯɿ1113 (2013/08/25) υΩϡϝϯτແ͍ʢʀ∀ʀʣ ιʔεʂˠJavaDocແ͍ʢʀ∀ʀʣɹɹɹ ςετˠཏ͞Εͯͳ͍ʢʀ∀ʀʣ 139݄28༵
ઃܭࢥతʹ ClojureͷCollectionͷ༷ʹՄೳͳݶΓԆධՁ MLܥݴޠͷ໊ؔʗϝιου໊Λ౿ऻ HaskellScalaܦݧऀೃછΈ͍͔͢ HamcrestͷMatcherΛPredicateʹ͑Δ static importଟ༻ 139݄28༵
ίʔυྫ̍ େےguavaͱมΘΒͳ͍ɻ mapͱ͔filterͱ͔static import͞Εͯ·͢ 139݄28༵
ίʔυྫ̎ υϠ ιʔεΛݟͳ͕ΒؤுΔ͔͠ͳ͍ؾ͕͢Δ sequence(foo)͕ɺJava8ͷStreamͷΠϝʔδ 139݄28༵
ॴײ ͱʹ͔͘υΩϡϝϯτ͕ແ͍ ઓಆྗͷ͕ܹ͍ࠩ͠ هड़ͱʹ͔͘؆ܿɻJava8ͷϥϜμࣜͰॻ͘ ΑΓ؆ܿɻ 139݄28༵
ҙ Java8ͷඪ४ϥΠϒϥϦͱΫϥε໊͕ඃΔ com.googlecode.totallylazy.Predicate newͰΠϯελϯεੜ͢ΔͷͰͳ ͘ɺSequences, PredicatesͳͲͳͲ͔Β static importͯ͠͏ͷ͕ఆੴ eclipseͩͱ͠ΜͲ͍Πϝʔδʢओ؍ 139݄28༵
139݄28༵
Java8 https:/ /jdk8.java.net/download.html ࠷৽όʔδϣϯɿ8 build b108 2014/03ϦϦʔε༧ఆʂ ؔܕػೳͷଞʹDateTimeͱ͔ɺσϑΥϧ τϝιουͱ͔ 139݄28༵
ίʔυྫ̍ ͜ͷॻ͖ํ͢ΔͱͲΕมΘΒͳ͍Ͱ͢Ͷ 139݄28༵
ίʔυྫ̎ ͜Ε͕Ұ൪͍ؾ͕͢Δ stream()ͯ͠ɺ࠷ޙʹList͢ ϥϜμࣜ͏ͱnew new͠ͳ͍͍ͯ͘ͷͰݟ ͍͢ 139݄28༵
͍ͭͰʹ guava/totallylazyͦΕͧΕϥϜμࣜͰ guava؆ܿʹͳͬͯGood totallylazyʹͳͬͯBad 139݄28༵
·ͱΊ Ϋϥε໊͕ඃͬͯ͘ΔͷͰɺҙ͠Α͏ totallylazy͑Δͱγϯϓϧ ˞ʮ͑Δͱʯ guavaίϨΫγϣϯϢʔςΟϦςΟͳͲ ͳ͑͘Δ 139݄28༵
͓ΘΓ 139݄28༵