値オブジェクトの悩みポイントとどう付き合っていくか

Transcript

1. ஋ΦϒδΣΫτͷ೰ΈϙΠϯτͱ
   Ͳ͏෇͖߹͍͔ͬͯ͘ !ZBDIJZ@
2. !ZBDIJZ@ IUUQTZBDIJZIBUFOBCMPHDPN ࠓճͷࢿྉ΍ࡌ͖ͤΕͳ͔ͬͨ
   ೰ΈϙΠϯτ͸ͪ͜ΒͰ΋ڞ༗͠·͢ʂ
3. ࿩͢͜ͱ
5. wϞσϧͱ࣮૷ΛΑΓਂ݁͘ͼ͚ͭΔ
   wෳࡶͳίʔυΛ໌നͰ༧ଌͰ͖Δ΋ͷʹ͢Δ ஋ΦϒδΣΫτΛ࣮૷͍ͯ͘͠ʹ͋ͨͬͯͷ೰ΈϙΠϯτ
6. Ͳ͜·Ͱܕͱͯ͠༻ҙ͢Δ͔
   /VMMBCMFͳ஋ΛऔΓѻ͏৔߹
   όϦσʔγϣϯͲ͜ʹॻ͔͘
   (FUUFS4FUUFSΛॻ͖ͨ͘ͳ͍͕ར༻ଆͰ಺෦ͷ஋Λࢀর͍ͨ͠ͱ͖Ͳ͏͢Δ͔
   Ͳ͜·ͰίϨΫγϣϯΦϒδΣΫτΛ༻ҙ͢Δ͔
   TUBUJDϑΝΫτϦϝιουΛ༻͍Δ΂͖͔
   ύοέʔδߏ੒Ͳ͏͢Δ͔
   JOOFS$MBTTΛ࢖͏΂͖͔൱͔ ೰Έ͕ͪ ࡉ͔͍࿩
7. Ͳ͜·Ͱܕͱͯ͠༻ҙ͢Δ͔
8. public class PersonName { private String firstName; private String lastName; public String fullName() { return String.format("%s %s", firstName, lastName); } } ͜ͷ͘Β͍ͳΒಛʹ೰·ͳ͍ ྫͷࢀরݩɿ
9. public class PersonName { private String firstName; private String lastName; public String fullName() { return String.format("%s %s", firstName, lastName); } } ݸผͷৼΔ෣͍͸ͳͦ͞͏ͳͷͰಛʹ೰·ͳ͍
10. public class PersonName { private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } }
11. public class PersonName { private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } ໊ࣈɺ໊લͱ͸ໟ৭͕ҧ͏
    ˠ
    ݸผͷৼΔ෣͍͕͋Γͦ͏
    ˠ
    ཁૉͷ஋ΦϒδΣΫτԽΛݕ౼
12. public class MiddleName { private static final int MIN_LENGTH = 1; private static final int MAX_LENGTH = 100; // null͕ೖΒͳ͍͜ͱ͸ݕূ͞Ε͍ͯΔ૝ఆ → ࢦఆ͕ͳ͍͜ͱ͸ۭจࣈͰදݱ private String value; // ίϯετϥΫλ΍ੜ੒ϝιουͰݕূ͢Δ͔ར༻ଆͰݕূ͔ͯ͠Β౉͔͢͸·ͨผͷ೰ΈϙΠϯτ… ... // ඞཁʹԠͯ͡༻ҙ public boolean isSpecified() { // value͕ۭจࣈͰͷੜ੒͸ڐͯ͠΋nullͰͷੜ੒͸ڐ͞ͳ͍ඞཁ͋Γ return !value.isEmpty(); } @Override public String toString() { return value; } ... }
13. public class MiddleName { private static final int MIN_LENGTH = 1; private static final int MAX_LENGTH = 100; // null͕ೖΒͳ͍͜ͱ͸ݕূ͞Ε͍ͯΔ૝ఆ → ࢦఆ͕ͳ͍͜ͱ͸ۭจࣈͰදݱ private String value; // ίϯετϥΫλ΍ੜ੒ϝιουͰݕূ͢Δ͔ར༻ଆͰݕূ͔ͯ͠Β౉͔͢͸·ͨผͷ೰ΈϙΠϯτ… ... // ඞཁʹԠͯ͡༻ҙ public boolean isSpecified() { // value͕ۭจࣈͰͷੜ੒͸ڐͯ͠΋nullͰͷੜ੒͸ڐ͞ͳ͍ඞཁ͋Γ return !value.isEmpty(); } @Override public String toString() { return value; } ... } ໊લ΍໊ࣈʹ΋ಉ༷ͷੑ࣭͸͋Γͦ͏
    ˠ
    4USJOH͔Β஋ΦϒδΣΫτԽΛݕ౼ͯ͠΋ྑͦ͞͏ ஋ͷൣғΛ੍ݶͯ͠ ϓϩάϥϜΛΘ͔Γ ΍҆͘͢શʹ
14. public class MiddleName { private static final int MIN_LENGTH = 1; private static final int MAX_LENGTH = 100; // null͕ೖΒͳ͍͜ͱ͸ݕূ͞Ε͍ͯΔ૝ఆ → ࢦఆ͕ͳ͍͜ͱ͸ۭจࣈͰදݱ private String value; // ίϯετϥΫλ΍ੜ੒ϝιουͰݕূ͢Δ͔ར༻ଆͰݕূ͔ͯ͠Β౉͔͢͸·ͨผͷ೰ΈϙΠϯτ… ... // ඞཁʹԠͯ͡༻ҙ public boolean isSpecified() { // value͕ۭจࣈͰͷੜ੒͸ڐͯ͠΋nullͰͷੜ੒͸ڐ͞ͳ͍ඞཁ͋Γ return !value.isEmpty(); } @Override public String toString() { return value; } ... } όϦσʔγϣϯΛͲ͜ʹஔ͔͘͸·ͨผͷ೰ΈϙΠϯτ
15. public class MiddleName { private static final int MIN_LENGTH = 1; private static final int MAX_LENGTH = 100; // null͕ೖΒͳ͍͜ͱ͸ݕূ͞Ε͍ͯΔ૝ఆ → ࢦఆ͕ͳ͍͜ͱ͸ۭจࣈͰදݱ private String value; // ίϯετϥΫλ΍ੜ੒ϝιουͰݕূ͢Δ͔ར༻ଆͰݕূ͔ͯ͠Β౉͔͢͸·ͨผͷ೰ΈϙΠϯτ… ... // ඞཁʹԠͯ͡༻ҙ public boolean isSpecified() { // value͕ۭจࣈͰͷੜ੒͸ڐͯ͠΋nullͰͷੜ੒͸ڐ͞ͳ͍ඞཁ͋Γ return !value.isEmpty(); } @Override public String toString() { return value; } ... } Ͳ͏ͯ͠΋ར༻ଆͰ஋ͷ͋Δͳ͠Λؾʹ͢ΔͳΒ࣮૷
16. public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; ... public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } }
17. public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; ... public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } ͜͜·Ͱຖճࡉ͔͘஋ΦϒδΣΫτԽ͢Δͷ͔
18. public class PersonName { private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } }
19. public class PersonName { private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private static final int MIN_FIRST_NAME_LANGTH = 1; private static final int MAX_FIRST_NAME_LENGTH = 100; private static final int MIN_MIDDLE_NAME_LENGTH = 1; private static final int MAX_MIDDLE_MAME_LENGTH = 100; private static final int MIN_LAST_NAME_LENGTH = 1; private static final int MAX_LAST_NAME_LENGTH = 100; private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } ্Ґ֓೦͕ߏ੒ཁૉͷ ஋ͷൣғΛ୲อ
20. public class PersonName { private static final int MIN_FIRST_NAME_LANGTH = 1; private static final int MAX_FIRST_NAME_LENGTH = 100; private static final int MIN_MIDDLE_NAME_LENGTH = 1; private static final int MAX_MIDDLE_MAME_LENGTH = 100; private static final int MIN_LAST_NAME_LENGTH = 1; private static final int MAX_LAST_NAME_LENGTH = 100; private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private String firstName; private String lastName; private String middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } public class PersonName { private FirstName firstName; private LastName lastName; private MiddleName middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } ্Ґ֓೦͕ߏ੒ཁૉͷ ஋ͷൣғΛ୲อ ಛʹมΘΓͳ͠
21. ஋ΦϒδΣΫτͷ਺Λ཈͑ΒΕΔ ্Ґ֓೦͕ߏ੒ཁૉͷੑ࣭΍ৼΔ෣͍΋୲อ ͢Δඞཁ͕͋Γݟ௨͕͠˚ ্Ґ֓೦ͷݟ௨͕͠˕ ஋ΦϒδΣΫτͷ਺͕૿͑Δ
    ʢதʹ͸΄΅ಉ͡Α͏ͳ΋ͷ΋ʣ ༻ҙ͞Ε͍ͯΔܕͷΈ ஋ΦϒδΣΫτͷΈ
22. ஋ΦϒδΣΫτͷ਺Λ཈͑ΒΕΔ ্Ґ֓೦͕ߏ੒ཁૉͷੑ࣭΍ৼΔ෣͍΋୲อ ͢Δඞཁ͕͋Γݟ௨͕͠˚ ্Ґ֓೦ͷݟ௨͕͠˕ ஋ΦϒδΣΫτͷ਺͕૿͑Δ
    ʢதʹ͸΄΅ಉ͡Α͏ͳ΋ͷ΋ʣ ༻ҙ͞Ε͍ͯΔܕͷΈ ஋ΦϒδΣΫτͷΈ ͡Ό͋ϋΠϒϦου͸ʁ
23. public class PersonName { private static final int MIN_FIRST_NAME_LANGTH = 1; private static final int MAX_FIRST_NAME_LENGTH = 100; private static final int MIN_LAST_NAME_LANGTH = 1; private static final int MAX_LAST_NAME_LENGTH = 100; private String firstName; private String lastName; private MiddleName middleName; public String fullName() { return String.format("%s %s %s", firstName, middleName, lastName); } } ϛυϧωʔϜ͚͕ͩಛघͱ͍͏ҙਤ͸఻ΘΓͦ͏ ཧղͷෛՙ͸ߴͦ͏
24. ؅ཧ͢Δߏ੒ཁૉ͕ଟ͘ͳ͍͔
    
    ɹɹˠ
    ੹຿͕ͭʹͳ͍ͬͯΔ͔
    
    
    ݸʑͷৼΔ෣͍΍ੑ࣭͕গͳ͍͔
    
    ɹɹˠ
    ஋ΦϒδΣΫτʹҠৡͨ͠΄͏͕γϯϓϧʹͳΒͳ͍͔
    Λݕ౼ গͳ͘ͱ΋ͭͷ֓೦ͷதͰ͸ͲͪΒ͔ʹ׬શʹ౗͢ ؾʹ͢Δ͜ͱ͕গͳ͍͏ͪ͸ ·ͱΊͯऔΓѻ͏͜ͱ΋ʜ ؾʹ͢Δ͜ͱ͕ଟ͘ͳ͖ͬͯͨΒؔ৺ࣄ ͝ͱʹऔΓѻ͍͍ͨ
25. Ͳ͜·Ͱܕͱͯ͠༻ҙ͢Δ͔
    /VMMBCMFͳ஋ΛऔΓѻ͏৔߹
    όϦσʔγϣϯͲ͜ʹॻ͔͘
    (FUUFS4FUUFSΛॻ͖ͨ͘ͳ͍͕ར༻ଆͰ಺෦ͷ஋Λࢀর͍ͨ͠ͱ͖Ͳ͏͢Δ͔
    Ͳ͜·ͰίϨΫγϣϯΦϒδΣΫτΛ༻ҙ͢Δ͔
    TUBUJDϑΝΫτϦϝιουΛ༻͍Δ΂͖͔
    ύοέʔδߏ੒Ͳ͏͢Δ͔
    JOOFS$MBTTΛ࢖͏΂͖͔൱͔ ೰Έ͕ͪ ࡉ͔͍࿩ օ༷͕ͲͷΑ͏ʹߟ͑ͯɺͲ͏ͯͦ͠ͷ࣮૷ʹͨ͠ͷ͔
    ͥͻͥͻɺ͓ฉ͔͍ͤͩ͘͞