Stream API 入門 #jjug #javajo

Java女子部「Java本格入門！！！著者をお招きしちゃうよ(*´∀`*) 」
https://javajo.doorkeeper.jp/events/60742

JJUG ナイトセミナー 「Java エンジニアのためのJava(再)入門」
https://jjug.doorkeeper.jp/events/61857

Transcript

1. 4USFBN"1*ೖ໳
   ʙ͍·͞Βฉ͚ͳ͍4USFBNͷΩϗϯ
   "DSPRVFTU5FDIOPMPHZגࣜձࣾ

   ೔ຊ+BWBϢʔβʔάϧʔϓ
   ୩ຊ৺ !DFSP@U
   
   

   View Slide

2. ͳͥɺ4USFBN"1*Λ

   ֶͿ΂͖ͳͷ͔ʁ
   

   View Slide

3. ৽͍͔͠Βʁ
   ੑೳ͕͍͍͔Βʁ
   ؆ܿʹॻ͚Δ͔Βʁ
   

   View Slide

4. 4USFBN"1*ͷΑ͏ͳ

   ෺ࣄͷଊ͑ํ͕ࠓޙ਺೥ͷ

   ίʔσΟϯάʹඞཁͱ

   ͳͬͯ͘Δ͔Β
   

   View Slide

5. ৄ͍͠࿩͸ޙͰ΍Γ·͢
   

   View Slide

6. ·ͣ͸ʮ؆ܿʹॻ͚Δ͔Βʯ

   ͩͱଊ͑ͯ࢝Ί·͠ΐ͏
   

   View Slide

7. 5BCMFPG$POUFOUT
   w 4USFBN"1*ͱ͸ʁ
   w -BNCEBࣜͱ͸ʁ
   w 4USFBN"1*ͷॻ͖ํͱɺԡ͑͞ΔϙΠϯτ
   w ͳͥ4USFBN"1*͕ॏཁͳͷ͔
   

   View Slide

8. 4USFBN"1*ͱ͸ʁ
   

   View Slide

9. 4USFBNྲྀΕ
   

   View Slide

10. View Slide

11. ৄ͍͠࿩͸ޙͰ΍Γ·͢
    

    View Slide

12. େྔσʔλΛஞ࣍ॲཧ͢Δ

    ʮετϦʔϜॲཧʯΛ

    ؆ܿʹॻͨ͘Ίͷ"1*
    

    View Slide

13. ͚ͩͲɺ

    ίϨΫγϣϯͷૢ࡞Λ

    ؆ܿʹॻ͘͜ͱ΋Ͱ͖Δ
    

    View Slide

14. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    for (Student student : students) {
    if (student.getScore() >= 70) {
    System.out.println(student);
    }
    }
    ͜Ε͕
    

    View Slide

15. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    

    students.stream()
    .filter(s -> s.getScore() >= 70)
    .forEach(System.out::println);
    ͜͏ͳΔ
    

    View Slide

16. ίϨΫγϣϯͷ

    ߜΓࠐΈɺม׵΍ɺ

    ͦΕͧΕͷཁૉ΁ͷॲཧɺ

    ूܭͳͲ͕Ͱ͖Δ
    

    View Slide

17. ͱ͸ݴ͑
    

    View Slide

18. Map groupByDeptAndFilter(List list) {
    return list.stream()
    .collect(Collectors.groupingBy(emp -> emp.dept))
    .entrySet()
    .stream()
    .collect(Collectors.toMap(entry -> entry.getKey(),
    entry -> entry.getValue()
    .stream()
    .filter(emp -> emp.sal > 1000)
    .count()));
    }
    

    View Slide

19. Կ͜ΕಡΊͳ͍
    

    View Slide

20. GPSจΛ࢖ͬͯ

    ॻ͖௚͢ͱ
    

    View Slide

21. Map groupByDeptClassic(List list) {
    Map result = new HashMap<>();
    for (Emp emp : list) {
    if (result.containsKey(emp.dept) == false) {
    result.put(emp.dept, 0L);
    }
    if (emp.sal > 1000) {
    Long count = result.get(emp.dept);
    count++;
    result.put(emp.dept, count);
    }
    }
    return result;
    }
    

    View Slide

22. ಡΈ΍͍͢ʂ

    ✌ Т✌
    ࡾ✌ Т
    ✌ࡾ ✌Т
    ✌
    

    View Slide

23. Έ͍ͨͳ͜ͱʹͳΔͷͰ

    ແཧͯ͠ෳࡶͳ΋ͷΛ

    4USFBN"1*Ͱ

    ॻ͘ඞཁ͸ͳ͍Ͱ͢
    

    View Slide

24. ৽͍͠΋ͷΛ࢖͏͜ͱ͕

    ৗʹΤϥ͍Θ͚͡Όͳ͍
    

    View Slide

25. ผʹੑೳ΋มΘΜͳ͍
    

    View Slide

26. ·ͣ͸جຊతͳॻ͖ํͱ

    ͦͷ֓೦Λֶͼ·͠ΐ͏
    

    View Slide

27. -BNCEBࣜͱ͸ʁ
    

    View Slide

28. ˓ϥϜμࣜ

    ºϥϯόμࣜ
    

    View Slide

29. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    

    students.stream()
    .filter(s -> s.getScore() >= 70)
    .forEach(System.out::println);
    ͜ͷ෦෼
    

    View Slide

30. 4USFBN"1*Λ

    ؆ܿʹॻͨ͘Ίʹ

    ͔ܽͤͳ͍΋ͷ
    

    View Slide

31. -BNCEBࣜͱ͸

    ࣮૷͢΂͖ϝιου͕

    ͔ͭ͠ͳ͍ΠϯλϑΣʔεΛ

    ؆ܿʹදهͰ͖Δ΋ͷ
    

    View Slide

32. ͨͱ͑͹
    KBWBVUJM$PNQBSBUPS

    

    ࣮૷͢Δ΂͖ϝιου͸

    DPNQBSF
    

    View Slide

33. void sort() {
    List studentList = new ArrayList<>();
    studentList.add(new Student("Murata", 100));
    studentList.add(new Student("Okada", 70));
    studentList.add(new Student("Tanimoto", 80));
    System.out.println(studentList);
    Collections.sort(studentList, new StudentComparator());
    System.out.println(studentList);
    }
    class StudentComparator implements Comparator {
    @Override
    public int compare(Student student1, Student student2) {
    return Integer.compare(student1.getScore(),
    student2.getScore());
    }
    }
    ͜ͷ෦෼
    

    View Slide

34. void sortAnonymous() {
    List studentList = new ArrayList<>();
    studentList.add(new Student("Murata", 100));
    studentList.add(new Student("Okada", 70));
    studentList.add(new Student("Tanimoto", 80));
    System.out.println(studentList);
    Collections.sort(studentList, new Comparator() {
    @Override
    public int compare(Student student1, Student student2) {
    return Integer.compare(student1.getScore(),
    student2.getScore());
    }
    });
    System.out.println(studentList);
    }
    ແ໊ΫϥεΛ࢖͏ͱ
    

    View Slide

35. void sortLambda() {
    List studentList = new ArrayList<>();
    studentList.add(new Student("Murata", 100));
    studentList.add(new Student("Okada", 70));
    studentList.add(new Student("Tanimoto", 80));
    System.out.println(studentList);
    Collections.sort(studentList, (student1, student2)
    -> Integer.compare(student1.getScore(), student2.getScore()));
    System.out.println(studentList);
    }
    -BNCEBΛ࢖͏ͱ
    

    View Slide

36. ࣮૷͢΂͖ϝιου͕

    ͔ͭ͠ͳ͍ΠϯλϑΣʔεΛ

    ʮؔ਺ܕΠϯλϑΣʔεʯ

    ͬͯݺͼ·͢
    

    View Slide

37. 4USFBN"1*ͷҾ਺͸

    جຊతʹ͢΂ͯ

    ؔ਺ܕΠϯλϑΣʔε
    

    View Slide

38. 4USFBN"1*Λ͢΂ͯ

    ແ໊ΫϥεͰ࡞Δͱ

    ಡΈͮΒͯ͘࢓ํͳ͍ͷͰ

    ؔ਺ͬΆ͘ॻ͚Δ

    -BNCEB͕ࣜಋೖ͞Εͨ
    

    View Slide

39. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    

    students.stream()
    .filter(s -> s.getScore() >= 70)
    .forEach(System.out::println);
    ΋͜͠Ε͕
    

    View Slide

40. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    students.stream()
    .filter(new Predicate() {
    @Override
    public boolean test(Student student) {
    return student.getScore() >= 70;
    }
    })
    .forEach(new Consumer() {
    @Override
    public void accept(Student student) {
    System.out.println(student);
    }
    });
    ͜͏ͳΒ
    

    View Slide

41. ୭΋͓લΛѪ͞ͳ͍
    

    View Slide

42. -BNCEBࣜͷจ๏
    

    View Slide

43. -BNCEBࣜͷجຊจ๏

    

    Ҿ਺
    \ॲཧ^
    

    View Slide

44. (Student student1, Student student2) -> {
    int score1 = student1.getScore();
    int score2 = student2.getScore();
    return Integer.compare(score1, score2);
    }
    (Student student) -> {

    System.out.println(student);
    }
    () -> {

    System.out.println("Hello!");
    }
    

    View Slide

45. Ҿ਺ͷܕ͸লུͰ͖Δ
    

    View Slide

46. (Student student1, Student student2) -> {
    int score1 = student1.getScore();
    int score2 = student2.getScore();
    return Integer.compare(score1, score2);
    }
    (student1, student2) -> {
    int score1 = student1.getScore();
    int score2 = student2.getScore();
    return Integer.compare(score1, score2);
    }
    

    View Slide

47. ॲཧ͕ߦͳΒ
    SFUVSOͱ\^͕

    লུͰ͖Δ
    

    View Slide

48. (student1, student2) -> {
    int score1 = student1.getScore();
    int score2 = student2.getScore();
    return Integer.compare(score1, score2);
    }
    

    

    (student1, student2) -> {
    return Integer.compare(student1.getScore(), student2.getScore());
    }
    (student1, student2) ->
    Integer.compare(student1.getScore(), student2.getScore())
    

    View Slide

49. Ҿ਺͕ͭͳΒ

    
    ΋লུͰ͖Δ
    

    View Slide

50. (Student student) -> {

    System.out.println(student);
    }
    

    

    

    student -> System.out.println(student)
    

    View Slide

51. -BNCEBͷத਎͕

    ϝιουݺͼग़ͭ͠Ͱ

    Ҿ਺΋໌֬ͳΒ

    ϝιουࢀর͕࢖͑Δ
    

    View Slide

52. ϝιουࢀরͷจ๏
    Ϋϥε໊ϝιου໊
    

    View Slide

53. (Student student) -> {

    System.out.println(student);
    }
    

    

    

    student -> System.out.println(student)
    System.out::println
    

    View Slide

54. (Student student) -> {

    return student.getScore();
    }
    

    

    

    student -> student.getScore();
    Student::getScore
    

    View Slide

55. List students = new ArrayList<>();
    students.add(new Student("Ken", 100));
    students.add(new Student("Shin", 60));
    students.add(new Student("Takuya", 80));
    

    students.stream()
    .filter(s -> s.getScore() >= 70)
    .forEach(System.out::println);
    ݁Ռɺ͜͏ͳΔ
    

    View Slide

56. ͜͜·Ͱ͸0,ʁ
    

    View Slide

57. 4USFBN"1*ͷॻ͖ํͱ

    ԡ͑͞ΔϙΠϯτ
    

    View Slide

58. ࡞Δ
    ૢ࡞͢Δ
    ·ͱΊΔ
    

    View Slide

59. Α͘࢖͏ύλʔϯ

    TUSFBN
    Ͱ࡞Γ
    NBQ
    ͰՃ޻͠

    pMUFS
    ͰߜΓࠐΈ

    DPMMFDU
    Ͱཉ͍͠ܗʹ͢Δ
    

    View Slide

60. ࡞Δ
    

    View Slide

61. 4USFBNΛฦ͢"1*Λ

    ݺͼग़͢͜ͱͰ

    4USFBNΛ࡞Δ
    

    View Slide

62. List lines
    = Arrays.asList("Murata=100", "Okada=60", "Tanimoto=80");
    List students = lines.stream()
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })
    .filter(s -> s.getScore() >= 70)
    .collect(Collectors.toList());
    $PMMFDUJPOTUSFBN
    
    

    View Slide

63. String[] lines = {"Murata=100", "Okada=60", "Tanimoto=80"};
    List students = Arrays.stream(lines)
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })
    .filter(s -> s.getScore() >= 70)
    .collect(Collectors.toList());
    "SSBZTTUSFBN
    
    

    View Slide

64. .BQͳΒ
    FOUSZ4FU
    TUSFBN
    
    ϑΝΠϧΛߦͣͭಡΉͳΒ
    'JMFTMJOFT
    
    #VGGFSFE3FBEFSMJOFT
    
    

    View Slide

65. ૢ࡞͢Δ

    ʢதؒૢ࡞ʣ
    

    View Slide

66. ઈରʹ֮͑ͯཉ͍͠
    NBQͱpMUFS
    

    View Slide

67. ม׵΍ߜΓࠐΈͳͲͷ

    ૢ࡞Λߦ͏ͷ͕தؒૢ࡞
    

    View Slide

68. NBQ

    ཁૉΛผͷཁૉʹม׵͢Δ
    pMUFS
    ৚݅Λࢦఆͯ͠ߜΓࠐΉ
    

    View Slide

69. List lines =
    Arrays.asList("Murata=100", "Okada=60", "Tanimoto=80");
    List students = lines.stream()
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })
    .filter(s -> s.getScore() >= 70)
    .collect(Collectors.toList());
    }
    NBQͱpMUFS
    

    View Slide

70. List lines =
    Arrays.asList("Murata=100", "Okada=60", "Tanimoto=80");
    List students = lines.stream()
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })

    // この時点でStudentのstreamになる
    .filter(s -> s.getScore() >= 70)
    // この時点でMurataとTanimotoが残ったstreamになる
    .collect(Collectors.toList());
    }
    NBQͱpMUFS
    

    View Slide

71. MJNJUͰ݅਺ΛߜΔ
    EJTUJODUͰϢχʔΫʹߜΔ

    TPSUFEͰฒ΂ม͑Δ

    ͳͲͳͲ
    

    View Slide

72. Α͋͘Δޡղࠞཚ
    

    View Slide

73. NBQͳͲͷม׵ॲཧͰ͸

    ཁૉͷ਺͸มΘΒͳ͍
    

    View Slide

74. ཁૉΛ͍͔ͭ͘·ͱΊͯ

    ॲཧ͢Δ

    Έ͍ͨͳ͜ͱ͸Ͱ͖ͳ͍

    ʢྫɿෳ਺ߦͷϩάϑΝΠϧॲཧʣ
    

    View Slide

75. ͋͘·Ͱɺ݅݅ɺ

    Կ͔͢Δ͍ͬͯ͏΋ͷ
    

    View Slide

76. pMUFSͰ෼ذ͢Δ͜ͱ͸

    Ͱ͖ͳ͍
    

    View Slide

77. ͜ͷ৚݅ͷ4USFBNɺ

    ͦͷ৚݅ͷ4USFBNɺ

    ͋ͷ৚݅ͷ4USFBNɺ

    ͲΕʹ΋֘౰͠ͳ͍4USFBN

    Έ͍ͨͳ͜ͱ͸Ͱ͖ͳ͍
    

    View Slide

78. ͋͘·Ͱ΋

    4USFBN͸ຊ
    

    View Slide

79. qBU.BQΛ࢖͑͹
    ͭͷཁૉ͔Β

    ෳ਺ͷཁૉΛ

    ࡞Δ͜ͱ͸Ͱ͖Δ
    

    View Slide

80. 
    
    
    ͔Β
    
    ͸࡞ΕΔ
    

    View Slide

81. Ͱ΋આ໌͸ׂѪ͢ΔΑʂ
    

    View Slide

82. ·ͱΊΔ

    ʢऴ୺ૢ࡞ʣ
    

    View Slide

83. 4USFBNΛ

    -JTUʹͨ͠Γ.BQʹͨ͠Γ
    ߹ܭ஋΍ฏۉ஋Λܭࢉͨ͠Γ
    

    View Slide

84. ࠷ޙʹ݁Ռͱͯ͠

    औΓग़͢΋ͷ͕

    ऴ୺ૢ࡞
    

    View Slide

85. Ұ൪࢖͏ͷ͕

    DPMMFDUͱ$PMMFDUPSTͷ

    ૊Έ߹Θͤ
    

    View Slide

86. List lines =
    Arrays.asList("Murata=100", "Okada=60", "Tanimoto=80");
    List students = lines.stream()
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })
    .filter(s -> s.getScore() >= 70)
    .collect(Collectors.toList());
    }
    DPMMFDU
    

    View Slide

87. $PMMFDUPSTUP4FU

    $PMMFDUPSTUP.BQ
    Ͱ4FU΍.BQʹม׵
    

    View Slide

88. String[] lines = {"Murata=100", "Okada=60", "Tanimoto=80"};
    Map students = Arrays.stream(lines)
    .map(s -> {
    String[] strings = s.split("=");
    return new Student(strings[0], Integer.valueOf(strings[1]));
    })
    .collect(Collectors.toMap(s -> s.getName(), s -> s));
    return students;
    $PMMFDUPSTUP.BQ
    

    View Slide

89. $PMMFDUPSTKPJOJOHͰ

    શ෦ͭͳ͛ͨจࣈྻʹม׵
    

    View Slide

90. $PMMFDUPSTHSPVQJOH#Z
    Ͱ

    -JTUͷ.BQΛ࡞Δ
    

    View Slide

91. DPMMFDUҎ֎ͷऴ୺ૢ࡞
    

    View Slide

92. GPS&BDI

    ೚ҙͷॲཧΛ͢Δ

    ʢ໭Γ஋ͳ͠ʣ
    

    View Slide

93. NBY NJO

    ࠷େͷ݅ɺ࠷খͷ݅ΛऔΔ
    pOE'JSTU

    ࠷ॳͷ݅ΛऔΔ
    

    View Slide

94. ਺஋ͷ4USFBNͳΒ

    BWFSBHFͱ͔΋औΕΔ
    

    View Slide

95. ཁ͢Δʹ

    4USFBNΛ

    ԿΒ͔ͷܗͰ

    ू໿ͯ͠औΓग़͢΋ͷ
    

    View Slide

96. ऴ୺ૢ࡞͸

    Ұճ͔͠Ͱ͖ͳ͍
    

    View Slide

97. UP-JTUͱGPS&BDIͷ

    ྆ํΛ͢Δ͜ͱ͸Ͱ͖ͳ͍
    

    View Slide

98. ͱ͍͏ลΓΛ౿·͑ͯ

    GSPNPME+BWB

    UPNPEFSO+BWB
    

    View Slide

99. List list = new ArrayList<>();
    try (BufferedReader reader = Files.newBufferedReader(Paths.get(fileName))) {
    String line;
    while ((line = reader.readLine()) != null) {
    String[] s = line.split(",");
    Transaction tx = new Transaction();
    tx.date = LocalDate.parse(s[0]);
    tx.accountId = s[1];
    tx.amount = Integer.valueOf(s[2]);
    tx.name = s[3];
    tx.note = s[4];
    list.add(tx);
    }
    } catch (IOException e) {
    throw new RuntimeException("failed to parse date or read file", e);
    }
    return list;
    GSPN
    

    View Slide

100. try (Stream stream = Files.lines(Paths.get(fileName))) {
     return stream
     .map(line -> {
     String[] s = line.split(",");
     Transaction tx = new Transaction();
     tx.date = LocalDate.parse(s[0]);
     tx.accountId = s[1];
     tx.amount = Integer.valueOf(s[2]);
     tx.name = s[3];
     tx.note = s[4];
     return tx;
     })
     .collect(Collectors.toList());
     } catch (IOException e) {
     throw new UncheckedIOException("failed to read file", e);
     }
     UP4USFBN
     

     View Slide

101. try (Stream stream = Files.lines(Paths.get(fileName))) {
     return stream
     .map(line -> {
     String[] s = line.split(",");
     Transaction tx = new Transaction();
     tx.date = LocalDate.parse(s[0]);
     tx.accountId = s[1];
     tx.amount = Integer.valueOf(s[2]);
     tx.name = s[3];
     tx.note = s[4];
     return tx;
     })
     .collect(Collectors.toList());
     } catch (IOException e) {
     throw new UncheckedIOException("failed to read file", e);
     }
     UP4USFBN
     ϑΝΠϧΛಡΈࠐΜͰ

     Streamͱͯ͠ฦ͢ϝιου

     ʢߦ͝ͱʹॲཧʣ
     ߦͷStringΛ

     Transactionʹม׵
     Listʹͯ͠ฦ͢
     

     View Slide

102. // 取引履歴の取得
     List list = read(fileName);
     // 全件表示
     for (Transaction tx : list) {
     System.out.println(tx);
     }
     // 残高の計算
     int sum = 0;
     for (Transaction tx : list) {
     sum += tx.amount;
     }
     System.out.println(sum);
     // 6月分のみ表示
     for (Transaction tx : list) {
     if (tx.date.getMonth() == Month.JUNE) {
     System.out.println(tx);
     }
     }
     GSPN
     

     View Slide

103. // 取引履歴の取得
     read(fileName).stream()
     .forEach(System.out::println);
     // 残高の計算
     int sum = read(fileName).stream()
     .mapToInt(tx -> tx.amount)
     .sum();
     System.out.println(sum);
     // 6月分のみ表示
     read(fileName).stream()
     .filter(tx -> tx.date.getMonth() == Month.JUNE)
     .forEach(System.out::println);
     UP4USFBN
     

     View Slide

104. // 取引履歴の取得
     read(fileName).stream()
     .forEach(System.out::println);
     // 残高の計算
     int sum = read(fileName).stream()
     .mapToInt(tx -> tx.amount)
     .sum();
     System.out.println(sum);
     // 6月分のみ表示
     read(fileName).stream()
     .filter(tx -> tx.date.getMonth() == Month.JUNE)
     .forEach(System.out::println);
     UP4USFBN
     ͢΂ͯͷཁૉʹ͍ͭͯ

     ॱ൪ʹॲཧ
     औҾֹΛint஋ͱͯ͠औΓग़ͯ͠

     intͷstreamʢIntStreamʣʹ͔ͯ͠Β

     ߹ܭ஋Λऔಘ
     6݄ͷΈΛऔΓग़ͯ͠

     શ݅දࣔ
     

     View Slide

105. ΋͏গ͠ࠐΈೖͬͨ಺༰͸

     ϥΠϒίʔσΟϯάͰ
     

     View Slide

106. ͳͥ4USFBN"1*͕

     ॏཁͳͷ͔ʁ
     

     View Slide

107. $PMMFDUJPOΛ؆ܿʹ

     ѻ͑ΔΑ͏ʹͳΔมΘΓʹ

     ݁ߏɺ֮͑Δ͜ͱ͕ଟ͍
     

     View Slide

108. େͯ͠༥௨΋ར͔ͳ͍
     

     View Slide

109. ͡Ό͊ͳΜͰ4USFBNΛ

     ࢖͏ͷ͔ʁ
     

     View Slide

110. 4USFBN"1*ͷ

     େ͖ͳ໨త͸

     4USFBNΛѻ͏͜ͱ
     

     View Slide

111. View Slide

112. $PMMFDUJPO͸

     طʹ಺༰͕ܾ·͍ͬͯΔ

     σʔλ
     ʢ$PME4USFBNʣ
     

     View Slide

113. ຊདྷͷ4USFBN͸

     ઈ͑ͣͯ͠

     ͔͠΋΋ͱͷਫʹ͋Βͣ
     

     View Slide

114. 8FCͷϦΫΤετ΍

     ΩϡʔΠϯάॲཧͳͲ
     ಺༰΍্ݶ͕

     ܾ·ͬͯͳ͍΋ͷ

     ʢ)PU4USFBNʣ
     

     View Slide

115. +BWBͷ4USFBN"1*͸

     جຊతʹ$PME4USFBNΛ

     ѻ͏ͨΊͷ΋ͷ
     

     View Slide

116. ओઓ৔͸)PU4USFBN
     

     View Slide

117. )PU4USFBNʹ

     ඞཁͳ΋ͷ
     

     View Slide

118. ΢Οϯυ΢ؔ਺
     

     View Slide

119. ྫɿ
     ਺ສͷηϯαʔ͔Β

     ૹ৴͞Εͨ৘ใΛ

     ड৴͠ͳ͕Β

     ूܭॲཧΛ͢Δ
     

     View Slide

120. ड৴ॲཧͱฒߦͯ͠ɺ

     ਺݅ͣͭ·ͱΊͯूܭ͢Δɺ

     ਺ඵͣͭूܭ͢Δɺ

     ໰୊͕͋Ε͹Ξϥʔτ
     

     View Slide

121. ͦΜͳ͜ͱ͕Ͱ͖Δ

     ΢Οϯυ΢ؔ਺͕ඞཁ
     

     View Slide

122. +BWBͰଟগ͸ೖΔ͕

     ࠓͷͱ͜Ζ͸

     3Y+BWB΍3FBDUPSΛ࢖͏
     

     View Slide

123. void monitorGauge(Flux input) {
     input.bufferTimeout(100, Duration.ofSeconds(10))
     .subscribe(list -> {
     DoubleSummaryStatistics stats = list.stream()
     .mapToDouble(Double::doubleValue)
     .summaryStatistics();
     if (stats.getMax() > maxThreshold) {
     alert(Level.WARNING);
     }
     if (stats.getAverage() > averageThreshold) {
     alert(Level.SEVERE);
     }
     });
     }
     3FBDUPSͷ"1*
     

     View Slide

124. void monitorGauge(Flux input) {
     input.bufferTimeout(100, Duration.ofSeconds(10))
     .subscribe(list -> {
     DoubleSummaryStatistics stats = list.stream()
     .mapToDouble(Double::doubleValue)
     .summaryStatistics();
     if (stats.getMax() > maxThreshold) {
     alert(Level.WARNING);
     }
     if (stats.getAverage() > averageThreshold) {
     alert(Level.SEVERE);
     }
     });
     }
     3FBDUPSͷ"1*
     100݅΋͘͠͸10ඵؒͷσʔλΛ

     ·ͱΊͯॲཧ͢Δ
     ʢूܭͯ͠ᮢ஋Λ௒͑ͨΒΞϥʔτʣ
     

     View Slide

125. ϊϯϒϩοΩϯά"1*
     

     View Slide

126. ྫɿ

     σʔλετΞ͔Β

     ສ݅ͷϨίʔυΛ

     औಘͨ͋͠ͱ

     ͦͷৄࡉσʔλΛ݅ͣͭ

     ສճऔಘ͢Δ
     

     View Slide

127. ֓ཁσʔλΛऔಘ͔ͯ͠Β

     ৄࡉσʔλΛऔಘ͢Δ
     

     View Slide

128. ͜Ε·Ͱ͸ಉظॲཧͰ

     σʔλϕʔεʹΞΫηε͢Δ

     Α͏ͳγεςϜΛͣͬͱ

     ࡞͖ͬͯ·ͨ͠
     

     View Slide

129. 42-Λສճ

     ൃߦ͢Δඞཁ͕͋Ε͹

     ॱ൪ʹສճൃߦͯ͠

     ੑೳ໰୊͕ى͖͍ͯ·ͨ͠
     

     View Slide

130. WebΞϓϦ DB
     1ສճͷSQLͰ

     ੑೳ໰୊͕ൃੜ
     

     View Slide

131. WebΞϓϦ DB
     ͪΐͬͱ޻෉ͯ͠

     গ͠ॏ͍ͨΫΤϦͰΧόʔ
     

     View Slide

132. ϚΠΫϩαʔϏε ϚΠΫϩαʔϏε
     1ສճͷαʔϏεݺͼग़͠
     

     View Slide

133. ϚΠΫϩαʔϏε ϚΠΫϩαʔϏε
     ͜ͷ1ສճͷαʔϏεݺͼग़͠Λ

     ʮͰ͖Δ͚ͩಉ࣌ʹʯ

     ࣮ߦ͍ͨ͠
     

     View Slide

134. ϊϯϒϩοΩϯάͳ

     ඇಉظ"1*ͱͯ͠

     ΍͸Γ

     3Y+BWBɺ3FBDUPSΛ࢖͏
     

     View Slide

135. Mono>> map =

     studentService.fetchStudents("1年3組")
     .flatMap(student -> scoreService.fetchScore(2017, student.id)

     .collectList()
     .map(scores -> Tuples.of(student, scores)))
     .collectMap(Tuple2::getT1, Tuple2::getT2);
     // 出力
     System.out.println(map.block());

     

     

     // 呼び出すAPI
     Flux fetchStudents(String className);
     Flux fetchScore(int year, int id)
     3FBDUPSͷ"1*
     

     View Slide

136. Mono>> map =

     studentService.fetchStudents("1年3組")
     .flatMap(student -> scoreService.fetchScore(2017, student.id)

     .collectList()
     .map(scores -> Tuples.of(student, scores)))
     .collectMap(Tuple2::getT1, Tuple2::getT2);
     // 出力
     System.out.println(map.block());

     

     

     // 呼び出すAPI
     Flux fetchStudents(String className);
     Flux fetchScore(int year, int id)
     3FBDUPSͷ"1*
     ʢৄࡉ͸ׂѪ͢Δ͚Ͳʣ

     APIݺͼग़͠ΛϊϯϒϩοΩϯά͔ͭ

     ඇಉظʹݺͼग़͢͜ͱͰ

     ॲཧશମͷ࣌ؒΛ୹ॖ

     ͔͠΋ར༻εϨου਺͕গͳ͍
     

     View Slide

137. ͜͏͍͏΋ͷ͸ɺ͢΂ͯ

     4USFBN"1*ͷΑ͏ͳ

     ܗͰهड़͞ΕΔ͜ͱʹͳΔ
     

     View Slide

138. ॲཧͷฒྻ౓Λ͋͛ͯ

     େྔσʔλ΍

     େྔϦΫΤετΛ

     ࡹ͘Α͏ͳ࣌୅
     

     View Slide

139. ͦ͜ʹ޲͚ͨ४උͱͯ͠

     4USFBN"1*Λ

     शಘ͍ͯͩ͘͠͞
     

     View Slide

140. -FU`T4UVEZ

     4USFBN"1*
     

     View Slide

141. Ξϯέʔτޚڠྗ͓ئ͍͠·͢

     IUUQCJUMZKKVH
     

     View Slide

142. +BWBຊ֨ೖ໳Λ

     ങͬͯͩ͘͞Δํ͸

     ͥͻ࿩͔͚͍ͯͩ͘͠͞
     

     View Slide