{"id":1958,"date":"2026-03-21T04:39:15","date_gmt":"2026-03-21T04:39:15","guid":{"rendered":"https:\/\/www.tech-posts.com\/vi\/polymorphism-basics-without-confusion\/"},"modified":"2026-03-21T04:39:15","modified_gmt":"2026-03-21T04:39:15","slug":"polymorphism-basics-without-confusion","status":"publish","type":"post","link":"https:\/\/www.tech-posts.com\/vi\/polymorphism-basics-without-confusion\/","title":{"rendered":"H\u01b0\u1edbng d\u1eabn OOAD: C\u01a1 b\u1ea3n v\u1ec1 \u0110a h\u00ecnh m\u00e0 Kh\u00f4ng G\u00e2y Nh\u1ea7m l\u1eabn"},"content":{"rendered":"
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\"Kawaii-style<\/figure>\n<\/div>\n

Hi\u1ec3u \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u00f2i h\u1ecfi ph\u1ea3i \u0111i qua nhi\u1ec1u kh\u00e1i ni\u1ec7m ph\u1ee9c t\u1ea1p, nh\u01b0ng \u00edt kh\u00e1i ni\u1ec7m n\u00e0o b\u1ecb hi\u1ec3u nh\u1ea7m nhi\u1ec1u nh\u01b0 \u0111a h\u00ecnh. Th\u01b0\u1eddng b\u1ecb che khu\u1ea5t b\u1edfi ng\u00f4n ng\u1eef h\u1ecdc thu\u1eadt, nguy\u00ean t\u1eafc n\u00e0y th\u1ef1c ra l\u00e0 m\u1ed9t trong nh\u1eefng c\u00f4ng c\u1ee5 th\u1ef1c ti\u1ec5n nh\u1ea5t \u0111\u1ec3 t\u1ea1o ra c\u00e1c h\u1ec7 th\u1ed1ng ph\u1ea7n m\u1ec1m linh ho\u1ea1t, d\u1ec5 b\u1ea3o tr\u00ec. B\u00e0i vi\u1ebft n\u00e0y gi\u1ea3i th\u00edch c\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh m\u00e0 kh\u00f4ng g\u00e2y nh\u1ea7m l\u1eabn, t\u1eadp trung v\u00e0o c\u00e1c \u0111\u1ecbnh ngh\u0129a r\u00f5 r\u00e0ng, logic th\u1ef1c t\u1ebf v\u00e0 t\u00ednh to\u00e0n v\u1eb9n c\u1ea5u tr\u00fac trong ph\u00e2n t\u00edch v\u00e0 thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng.<\/p>\n

Ch\u00fang ta s\u1ebd kh\u00e1m ph\u00e1 c\u00e1ch c\u01a1 ch\u1ebf n\u00e0y cho ph\u00e9p c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ph\u1ea3n h\u1ed3i kh\u00e1c nhau tr\u01b0\u1edbc c\u00f9ng m\u1ed9t th\u00f4ng \u0111i\u1ec7p, t\u1ea1i sao \u0111i\u1ec1u n\u00e0y quan tr\u1ecdng \u0111\u1ed1i v\u1edbi s\u1ee9c kh\u1ecfe m\u00e3 ngu\u1ed3n d\u00e0i h\u1ea1n, v\u00e0 c\u00e1ch tri\u1ec3n khai n\u00f3 hi\u1ec7u qu\u1ea3 m\u00e0 kh\u00f4ng l\u00e0m qu\u00e1 ph\u1ee9c t\u1ea1p ki\u1ebfn tr\u00fac c\u1ee7a b\u1ea1n. H\u00e3y c\u00f9ng \u0111i s\u00e2u v\u00e0o b\u1ea3n ch\u1ea5t c\u1ee7a n\u00f3.<\/p>\n

\u0110\u1ecbnh ngh\u0129a Kh\u00e1i ni\u1ec7m C\u1ed1t l\u00f5i \ud83e\udde0<\/h2>\n

\u0110\u01a1n gi\u1ea3n nh\u1ea5t, \u0111a h\u00ecnh cho ph\u00e9p c\u00e1c lo\u1ea1i \u0111\u1ed1i t\u01b0\u1ee3ng kh\u00e1c nhau \u0111\u01b0\u1ee3c x\u1eed l\u00fd nh\u01b0 th\u1ec3 ch\u00fang l\u00e0 c\u00e1c th\u1ec3 hi\u1ec7n c\u1ee7a m\u1ed9t ki\u1ec3u si\u00eau chung. T\u1eeb n\u00e0y xu\u1ea5t ph\u00e1t t\u1eeb g\u1ed1c Hy L\u1ea1p c\u00f3 ngh\u0129a l\u00e0 \u201cnhi\u1ec1u h\u00ecnh th\u1ee9c\u201d. Trong b\u1ed1i c\u1ea3nh ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m, \u0111i\u1ec1u \u0111\u00f3 c\u00f3 ngh\u0129a l\u00e0 m\u1ed9t giao di\u1ec7n duy nh\u1ea5t c\u00f3 th\u1ec3 \u0111\u1ea1i di\u1ec7n cho nhi\u1ec1u d\u1ea1ng ho\u1eb7c ki\u1ec3u d\u1eef li\u1ec7u n\u1ec1n t\u1ea3ng kh\u00e1c nhau.<\/p>\n

H\u00e3y xem x\u00e9t m\u1ed9t t\u00ecnh hu\u1ed1ng m\u00e0 b\u1ea1n c\u00f3 m\u1ed9t h\u1ec7 th\u1ed1ng qu\u1ea3n l\u00fd c\u00e1c h\u00ecnh d\u1ea1ng kh\u00e1c nhau. B\u1ea1n c\u00f3 th\u1ec3 c\u00f3 h\u00ecnh tr\u00f2n, h\u00ecnh vu\u00f4ng v\u00e0 h\u00ecnh tam gi\u00e1c. N\u1ebfu b\u1ea1n c\u1ea7n t\u00ednh di\u1ec7n t\u00edch c\u1ee7a t\u1eebng h\u00ecnh, \u0111a h\u00ecnh cho ph\u00e9p b\u1ea1n vi\u1ebft m\u1ed9t h\u00e0m ch\u1ea5p nh\u1eadn m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng \u201cH\u00ecnh d\u1ea1ng\u201d chung. D\u00f9 \u0111\u1ed1i t\u01b0\u1ee3ng c\u1ee5 th\u1ec3 l\u00e0 h\u00ecnh tr\u00f2n hay h\u00ecnh vu\u00f4ng, h\u00e0m v\u1eabn g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c t\u00ednh to\u00e1n ph\u00f9 h\u1ee3p b\u00ean trong m\u00e0 kh\u00f4ng c\u1ea7n bi\u1ebft tr\u01b0\u1edbc lo\u1ea1i c\u1ee5 th\u1ec3.<\/p>\n

C\u00e1ch ti\u1ebfp c\u1eadn n\u00e0y gi\u1ea3m s\u1ef1 ph\u1ee5 thu\u1ed9c. M\u00e3 c\u1ee7a b\u1ea1n kh\u00f4ng c\u1ea7n bi\u1ebft chi ti\u1ebft tri\u1ec3n khai c\u1ee5 th\u1ec3 c\u1ee7a t\u1eebng h\u00ecnh \u0111\u1ec3 th\u1ef1c hi\u1ec7n h\u00e0nh \u0111\u1ed9ng tr\u00ean ch\u00fang. N\u00f3 ch\u1ec9 c\u1ea7n bi\u1ebft r\u1eb1ng \u0111\u1ed1i t\u01b0\u1ee3ng tu\u00e2n th\u1ee7 giao di\u1ec7n mong mu\u1ed1n.<\/p>\n

\u0110\u1eb7c \u0111i\u1ec3m ch\u00ednh<\/h3>\n
    \n
  • T\u00ednh linh ho\u1ea1t:<\/strong>C\u00e1c lo\u1ea1i m\u1edbi c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u00eam v\u00e0o m\u00e0 kh\u00f4ng c\u1ea7n s\u1eeda \u0111\u1ed5i m\u00e3 hi\u1ec7n c\u00f3 s\u1eed d\u1ee5ng giao di\u1ec7n c\u01a1 s\u1edf.<\/li>\n
  • T\u00ednh m\u1edf r\u1ed9ng:<\/strong>H\u1ec7 th\u1ed1ng ph\u00e1t tri\u1ec3n m\u1ed9t c\u00e1ch t\u1ef1 nhi\u00ean khi y\u00eau c\u1ea7u thay \u0111\u1ed5i.<\/li>\n
  • T\u00ednh tr\u1eebu t\u01b0\u1ee3ng:<\/strong>Chi ti\u1ebft tri\u1ec3n khai \u0111\u01b0\u1ee3c che gi\u1ea5u ph\u00eda sau m\u1ed9t giao di\u1ec7n th\u1ed1ng nh\u1ea5t.<\/li>\n<\/ul>\n

    G\u00e1n t\u0129nh so v\u1edbi G\u00e1n \u0111\u1ed9ng \u2696\ufe0f<\/h2>\n

    \u0110\u1ec3 th\u1ef1c s\u1ef1 hi\u1ec3u \u0111\u01b0\u1ee3c \u0111a h\u00ecnh, ta ph\u1ea3i ph\u00e2n bi\u1ec7t c\u00e1ch th\u1ee9c g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft. S\u1ef1 ph\u00e2n bi\u1ec7t n\u00e0y r\u1ea5t quan tr\u1ecdng \u0111\u1ed1i v\u1edbi hi\u1ec7u su\u1ea5t v\u00e0 d\u1ef1 \u0111o\u00e1n h\u00e0nh vi.<\/p>\n

    1. \u0110a h\u00ecnh th\u1eddi gian bi\u00ean d\u1ecbch (T\u0129nh)<\/h3>\n

    \u0110i\u1ec1u n\u00e0y x\u1ea3y ra khi ph\u01b0\u01a1ng th\u1ee9c c\u1ea7n th\u1ef1c thi \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh b\u1edfi tr\u00ecnh bi\u00ean d\u1ecbch tr\u01b0\u1edbc khi ch\u01b0\u01a1ng tr\u00ecnh ch\u1ea1y. N\u00f3 ph\u1ee5 thu\u1ed9c v\u00e0o ch\u1eef k\u00fd ph\u01b0\u01a1ng th\u1ee9c.<\/p>\n

      \n
    • Ghi \u0111\u00e8 ph\u01b0\u01a1ng th\u1ee9c:<\/strong>Nhi\u1ec1u ph\u01b0\u01a1ng th\u1ee9c chia s\u1ebb c\u00f9ng m\u1ed9t t\u00ean nh\u01b0ng kh\u00e1c nhau \u1edf danh s\u00e1ch tham s\u1ed1 (s\u1ed1 l\u01b0\u1ee3ng ho\u1eb7c ki\u1ec3u tham s\u1ed1).<\/li>\n
    • Ghi \u0111\u00e8 to\u00e1n t\u1eed:<\/strong>C\u00e1c to\u00e1n t\u1eed \u0111\u01b0\u1ee3c g\u00e1n \u00fd ngh\u0129a \u0111\u1eb7c bi\u1ec7t cho c\u00e1c ki\u1ec3u do ng\u01b0\u1eddi d\u00f9ng \u0111\u1ecbnh ngh\u0129a c\u1ee5 th\u1ec3.<\/li>\n
    • Gi\u1ea3i quy\u1ebft:<\/strong>Tr\u00ecnh bi\u00ean d\u1ecbch xem x\u00e9t ki\u1ec3u bi\u1ebfn v\u00e0 c\u00e1c \u0111\u1ed1i s\u1ed1 \u0111\u01b0\u1ee3c cung c\u1ea5p \u0111\u1ec3 quy\u1ebft \u0111\u1ecbnh ph\u01b0\u01a1ng th\u1ee9c n\u00e0o s\u1ebd g\u1ecdi.<\/li>\n<\/ul>\n

      2. \u0110a h\u00ecnh th\u1eddi gian ch\u1ea1y (\u0110\u1ed9ng)<\/h3>\n

      \u0110i\u1ec1u n\u00e0y x\u1ea3y ra khi ph\u01b0\u01a1ng th\u1ee9c c\u1ea7n th\u1ef1c thi \u0111\u01b0\u1ee3c x\u00e1c \u0111\u1ecbnh trong qu\u00e1 tr\u00ecnh ch\u01b0\u01a1ng tr\u00ecnh \u0111ang ch\u1ea1y. N\u00f3 ph\u1ee5 thu\u1ed9c v\u00e0o th\u1ec3 hi\u1ec7n \u0111\u1ed1i t\u01b0\u1ee3ng th\u1ef1c t\u1ebf, ch\u1ee9 kh\u00f4ng ch\u1ec9 ki\u1ec3u tham chi\u1ebfu.<\/p>\n

        \n
      • Ghi \u0111\u00e8 ph\u01b0\u01a1ng th\u1ee9c:<\/strong>L\u1edbp con cung c\u1ea5p m\u1ed9t tri\u1ec3n khai c\u1ee5 th\u1ec3 cho m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u1ecbnh ngh\u0129a trong l\u1edbp cha c\u1ee7a n\u00f3.<\/li>\n
      • Ph\u00e2n ph\u00e1t \u0111\u1ed9ng:<\/strong>M\u00e1y \u1ea3o gi\u1ea3i quy\u1ebft cu\u1ed9c g\u1ecdi d\u1ef1a tr\u00ean ki\u1ec3u th\u1ef1c thi c\u1ee7a \u0111\u1ed1i t\u01b0\u1ee3ng.<\/li>\n
      • Gi\u1ea3i ph\u00e1p:<\/strong>Quy\u1ebft \u0111\u1ecbnh ch\u1ec9 \u0111\u01b0\u1ee3c \u0111\u01b0a ra khi m\u00e3 \u0111\u01b0\u1ee3c th\u1ef1c thi.<\/li>\n<\/ul>\n

        Hi\u1ec3u \u0111\u01b0\u1ee3c s\u1ef1 kh\u00e1c bi\u1ec7t gi\u1eefa hai th\u1eddi \u0111i\u1ec3m g\u00e1n n\u00e0y l\u00e0 \u0111i\u1ec1u c\u1ea7n thi\u1ebft cho vi\u1ec7c g\u1ee1 l\u1ed7i v\u00e0 t\u1ed1i \u01b0u hi\u1ec7u su\u1ea5t. G\u00e1n t\u0129nh th\u01b0\u1eddng nhanh h\u01a1n, nh\u01b0ng g\u00e1n \u0111\u1ed9ng cung c\u1ea5p s\u1ef1 linh ho\u1ea1t c\u1ea7n thi\u1ebft cho c\u00e1c c\u1ea5u tr\u00fac \u0111\u1ed1i t\u01b0\u1ee3ng ph\u1ee9c t\u1ea1p.<\/p>\n

        Ghi \u0111\u00e8 vs Ghi \u0111\u00e8 l\u1ea1i \u2699\ufe0f<\/h2>\n

        Nh\u1eefng thu\u1eadt ng\u1eef n\u00e0y th\u01b0\u1eddng \u0111\u01b0\u1ee3c d\u00f9ng thay th\u1ebf cho nhau b\u1edfi ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u, nh\u01b0ng ch\u00fang ph\u1ee5c v\u1ee5 nh\u1eefng m\u1ee5c \u0111\u00edch kh\u00e1c nhau trong thi\u1ebft k\u1ebf.<\/p>\n\n\n\n\n\n\n\n\n\n
        T\u00ednh n\u0103ng<\/th>\nGhi \u0111\u00e8 ph\u01b0\u01a1ng th\u1ee9c<\/th>\nGhi \u0111\u00e8 ph\u01b0\u01a1ng th\u1ee9c<\/th>\n<\/tr>\n<\/thead>\n
        Ph\u1ea1m vi<\/strong><\/td>\nTrong c\u00f9ng m\u1ed9t l\u1edbp<\/td>\nGi\u1eefa l\u1edbp cha v\u00e0 l\u1edbp con<\/td>\n<\/tr>\n
        Tham s\u1ed1<\/strong><\/td>\nPh\u1ea3i kh\u00e1c nhau<\/td>\nPh\u1ea3i gi\u1ed1ng nhau<\/td>\n<\/tr>\n
        Th\u1eddi \u0111i\u1ec3m g\u00e1n<\/strong><\/td>\nTh\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch<\/td>\nTh\u1eddi \u0111i\u1ec3m ch\u1ea1y<\/td>\n<\/tr>\n
        Ki\u1ec3u tr\u1ea3 v\u1ec1<\/strong><\/td>\nC\u00f3 th\u1ec3 kh\u00e1c nhau<\/td>\nPh\u1ea3i gi\u1ed1ng nhau ho\u1eb7c b\u1ea5t bi\u1ebfn<\/td>\n<\/tr>\n
        M\u1ee5c \u0111\u00edch ch\u00ednh<\/strong><\/td>\nTi\u1ec7n l\u1ee3i, ch\u1ee9c n\u0103ng t\u01b0\u01a1ng t\u1ef1<\/td>\nS\u1eeda \u0111\u1ed5i h\u00e0nh vi, chuy\u00ean bi\u1ec7t h\u00f3a<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

        Ghi \u0111\u00e8 l\u00e0 v\u1ec1 s\u1ef1 ti\u1ec7n l\u1ee3i. N\u00f3 cho ph\u00e9p b\u1ea1n \u0111\u1eb7t t\u00ean ph\u01b0\u01a1ng th\u1ee9c `t\u00ednh to\u00e1n` d\u00f9 b\u1ea1n \u0111ang truy\u1ec1n m\u1ed9t b\u00e1n k\u00ednh duy nh\u1ea5t hay c\u1ea3 chi\u1ec1u r\u1ed9ng v\u00e0 chi\u1ec1u cao. Ghi \u0111\u00e8 l\u1ea1i l\u00e0 v\u1ec1 chuy\u00ean bi\u1ec7t h\u00f3a. N\u00f3 cho ph\u00e9p m\u1ed9t l\u1edbp `Ph\u01b0\u01a1ng ti\u1ec7n` \u0111\u1ecbnh ngh\u0129a ph\u01b0\u01a1ng th\u1ee9c `di chuy\u1ec3n()`, trong khi l\u1edbp con `Xe h\u01a1i` ghi \u0111\u00e8 n\u00f3 \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1ch b\u00e1nh xe quay, v\u00e0 l\u1edbp con `Thuy\u1ec1n` ghi \u0111\u00e8 n\u00f3 \u0111\u1ec3 x\u00e1c \u0111\u1ecbnh c\u00e1ch c\u00e1nh qu\u1ea1t quay.<\/p>\n

        Vai tr\u00f2 c\u1ee7a giao di\u1ec7n \ud83d\udd17<\/h2>\n

        Trong thi\u1ebft k\u1ebf hi\u1ec7n \u0111\u1ea1i, t\u00ednh \u0111a h\u00ecnh th\u01b0\u1eddng \u0111\u01b0\u1ee3c \u0111\u1ea1t \u0111\u01b0\u1ee3c th\u00f4ng qua giao di\u1ec7n thay v\u00ec ch\u1ec9 k\u1ebf th\u1eeba. M\u1ed9t giao di\u1ec7n \u0111\u1ecbnh ngh\u0129a m\u1ed9t h\u1ee3p \u0111\u1ed3ng. N\u00f3 x\u00e1c \u0111\u1ecbnh nh\u1eefng ph\u01b0\u01a1ng th\u1ee9c m\u00e0 m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng ph\u1ea3i c\u00f3, m\u00e0 kh\u00f4ng quy \u0111\u1ecbnh c\u00e1ch ch\u00fang ho\u1ea1t \u0111\u1ed9ng.<\/p>\n

        T\u1ea1i sao n\u00ean s\u1eed d\u1ee5ng giao di\u1ec7n?<\/h3>\n
          \n
        • K\u1ebft n\u1ed1i l\u1ecfng l\u1ebbo:<\/strong>M\u00e3 ph\u1ee5 thu\u1ed9c v\u00e0o giao di\u1ec7n, ch\u1ee9 kh\u00f4ng ph\u1ea3i v\u00e0o tri\u1ec3n khai c\u1ee5 th\u1ec3.<\/li>\n
        • M\u00f4 ph\u1ecfng k\u1ebf th\u1eeba nhi\u1ec1u l\u1edbp:<\/strong> M\u1ed9t l\u1edbp c\u00f3 th\u1ec3 tri\u1ec3n khai nhi\u1ec1u giao di\u1ec7n, \u0111\u1ea1t \u0111\u01b0\u1ee3c k\u1ebf th\u1eeba ki\u1ec3u \u0111a d\u1ea1ng.<\/li>\n
        • Ki\u1ec3m th\u1eed:<\/strong> C\u00e1c giao di\u1ec7n gi\u00fap vi\u1ec7c t\u1ea1o \u0111\u1ed1i t\u01b0\u1ee3ng gi\u1ea3 (mock objects) cho ki\u1ec3m th\u1eed \u0111\u01a1n v\u1ecb tr\u1edf n\u00ean d\u1ec5 d\u00e0ng h\u01a1n.<\/li>\n<\/ul>\n

          Khi b\u1ea1n l\u1eadp tr\u00ecnh d\u1ef1a tr\u00ean m\u1ed9t giao di\u1ec7n, b\u1ea1n \u0111\u1ea3m b\u1ea3o r\u1eb1ng b\u1ea5t k\u1ef3 l\u1edbp n\u00e0o tri\u1ec3n khai giao di\u1ec7n \u0111\u00f3 \u0111\u1ec1u c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c thay th\u1ebf m\u00e0 kh\u00f4ng l\u00e0m h\u1ecfng logic ti\u00eau th\u1ee5 n\u00f3. \u0110\u00e2y ch\u00ednh l\u00e0 b\u1ea3n ch\u1ea5t c\u1ee7a Nguy\u00ean t\u1eafc \u0110\u1ea3o ng\u01b0\u1ee3c Ph\u1ee5 thu\u1ed9c, n\u1ec1n t\u1ea3ng c\u1ed1t l\u00f5i cho thi\u1ebft k\u1ebf v\u1eefng ch\u1eafc.<\/p>\n

          C\u00e1c M\u1eabu Thi\u1ebft k\u1ebf S\u1eed d\u1ee5ng \u0110a h\u00ecnh \ud83c\udfd7\ufe0f<\/h2>\n

          Nhi\u1ec1u m\u1eabu thi\u1ebft k\u1ebf \u0111\u00e3 \u0111\u01b0\u1ee3c x\u00e1c l\u1eadp ph\u1ee5 thu\u1ed9c m\u1ea1nh v\u00e0o \u0111a h\u00ecnh \u0111\u1ec3 gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 l\u1eb7p l\u1ea1i.<\/p>\n

          1. M\u1eabu Chi\u1ebfn l\u01b0\u1ee3c<\/h3>\n

          M\u1eabu n\u00e0y \u0111\u1ecbnh ngh\u0129a m\u1ed9t gia \u0111\u00ecnh c\u00e1c thu\u1eadt to\u00e1n, \u0111\u00f3ng g\u00f3i t\u1eebng thu\u1eadt to\u00e1n v\u00e0 l\u00e0m cho ch\u00fang c\u00f3 th\u1ec3 thay th\u1ebf l\u1eabn nhau. M\u00e3 kh\u00e1ch h\u00e0ng ch\u1ecdn thu\u1eadt to\u00e1n c\u1ee5 th\u1ec3 t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1y.<\/p>\n

            \n
          • V\u00ed d\u1ee5:<\/strong> M\u1ed9t b\u1ed9 x\u1eed l\u00fd thanh to\u00e1n c\u00f3 th\u1ec3 ch\u1ea5p nh\u1eadn giao di\u1ec7n `PaymentStrategy`. B\u1ea1n c\u00f3 th\u1ec3 ch\u00e8n `CreditCardStrategy` ho\u1eb7c `CryptoStrategy` t\u00f9y theo s\u1edf th\u00edch ng\u01b0\u1eddi d\u00f9ng m\u00e0 kh\u00f4ng c\u1ea7n thay \u0111\u1ed5i logic thanh to\u00e1n.<\/li>\n<\/ul>\n

            2. M\u1eabu Nh\u00e0 m\u00e1y<\/h3>\n

            C\u00e1c ph\u01b0\u01a1ng th\u1ee9c nh\u00e0 m\u00e1y cho ph\u00e9p m\u1ed9t l\u1edbp kh\u1edfi t\u1ea1o m\u1ed9t trong s\u1ed1 nhi\u1ec1u l\u1edbp con d\u1ef1a tr\u00ean ng\u1eef c\u1ea3nh. Ng\u01b0\u1eddi g\u1ecdi nh\u1eadn \u0111\u01b0\u1ee3c m\u1ed9t ki\u1ec3u t\u1ed5ng qu\u00e1t, nh\u01b0ng \u0111a h\u00ecnh s\u1ebd x\u1eed l\u00fd logic t\u1ea1o c\u1ee5 th\u1ec3.<\/p>\n

            3. M\u1eabu Ng\u01b0\u1eddi quan s\u00e1t<\/h3>\n

            Khi m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i, n\u00f3 th\u00f4ng b\u00e1o \u0111\u1ebfn m\u1ed9t danh s\u00e1ch c\u00e1c ng\u01b0\u1eddi quan s\u00e1t. \u0110\u1ed1i t\u01b0\u1ee3ng ch\u1ee7 kh\u00f4ng bi\u1ebft ki\u1ec3u c\u1ee5 th\u1ec3 c\u1ee7a ng\u01b0\u1eddi quan s\u00e1t, ch\u1ec9 bi\u1ebft r\u1eb1ng n\u00f3 tri\u1ec3n khai ph\u01b0\u01a1ng th\u1ee9c `notify`.<\/p>\n

            Nh\u1eefng hi\u1ec3u l\u1ea7m ph\u1ed5 bi\u1ebfn \u274c<\/h2>\n

            C\u00f3 m\u1ed9t s\u1ed1 huy\u1ec1n tho\u1ea1i xung quanh kh\u00e1i ni\u1ec7m n\u00e0y th\u01b0\u1eddng d\u1eabn \u0111\u1ebfn c\u00e1c quy\u1ebft \u0111\u1ecbnh thi\u1ebft k\u1ebf k\u00e9m hi\u1ec7u qu\u1ea3.<\/p>\n

              \n
            • Huy\u1ec1n tho\u1ea1i 1: \u0110a h\u00ecnh \u0111\u00f2i h\u1ecfi c\u00e1c c\u00e2y k\u1ebf th\u1eeba s\u00e2u.<\/strong>\n

              Sai. M\u1eb7c d\u00f9 k\u1ebf th\u1eeba l\u00e0 ph\u01b0\u01a1ng ti\u1ec7n ph\u1ed5 bi\u1ebfn, nh\u01b0ng vi\u1ec7c k\u1ebft h\u1ee3p (composition) v\u00e0 giao di\u1ec7n th\u01b0\u1eddng cung c\u1ea5p \u0111a h\u00ecnh t\u1ed1t h\u01a1n m\u00e0 kh\u00f4ng c\u1ea7n ph\u1ea3i lo l\u1eafng v\u1ec1 s\u1ef1 mong manh c\u1ee7a c\u00e1c c\u1ea5u tr\u00fac k\u1ebf th\u1eeba s\u00e2u. \u01afu ti\u00ean k\u1ebft h\u1ee3p h\u01a1n l\u00e0 k\u1ebf th\u1eeba.<\/p>\n<\/li>\n

            • Huy\u1ec1n tho\u1ea1i 2: N\u00f3 l\u00e0m m\u00e3 ngu\u1ed3n ch\u1eadm h\u01a1n.<\/strong>\n

              Vi\u1ec7c ph\u00e2n ph\u00e1t \u0111\u1ed9ng th\u00eam m\u1ed9t chi ph\u00ed nh\u1ecf so v\u1edbi c\u00e1c l\u1eddi g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c tr\u1ef1c ti\u1ebfp. Tuy nhi\u00ean, c\u00e1c t\u1ed1i \u01b0u h\u00f3a th\u1eddi gian ch\u1ea1y hi\u1ec7n \u0111\u1ea1i th\u01b0\u1eddng gi\u1ea3m thi\u1ec3u \u0111i\u1ec1u n\u00e0y. L\u1ee3i \u00edch v\u1ec1 kh\u1ea3 n\u0103ng b\u1ea3o tr\u00ec th\u01b0\u1eddng v\u01b0\u1ee3t tr\u1ed9i h\u01a1n chi ph\u00ed t\u1ed1i \u01b0u h\u00f3a vi m\u00f4.<\/p>\n<\/li>\n

            • Huy\u1ec1n tho\u1ea1i 3: M\u1ecdi l\u1edbp \u0111\u1ec1u n\u00ean h\u1ed7 tr\u1ee3 n\u00f3.<\/strong>\n

              Sai. Kh\u00f4ng ph\u1ea3i m\u1ecdi l\u1edbp n\u00e0o c\u0169ng c\u1ea7n ph\u1ea3i \u0111a h\u00ecnh. S\u1eed d\u1ee5ng n\u00f3 \u1edf nh\u1eefng n\u01a1i h\u00e0nh vi thay \u0111\u1ed5i d\u1ef1a tr\u00ean ki\u1ec3u. N\u1ebfu t\u1ea5t c\u1ea3 c\u00e1c th\u1ec3 hi\u1ec7n \u0111\u1ec1u h\u00e0nh x\u1eed gi\u1ed1ng nhau, th\u00ec \u0111a h\u00ecnh s\u1ebd th\u00eam s\u1ef1 ph\u1ee9c t\u1ea1p kh\u00f4ng c\u1ea7n thi\u1ebft.<\/p>\n<\/li>\n<\/ul>\n

              Khi n\u00e0o n\u00ean tr\u00e1nh n\u00f3 \ud83d\uded1<\/h2>\n

              M\u1eb7c d\u00f9 m\u1ea1nh m\u1ebd, nh\u01b0ng \u0111a h\u00ecnh kh\u00f4ng ph\u1ea3i l\u00e0 gi\u1ea3i ph\u00e1p ph\u1ed5 qu\u00e1t. \u00c1p d\u1ee5ng n\u00f3 m\u1ed9t c\u00e1ch b\u1eeba b\u00e3i c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn m\u00e3 ngu\u1ed3n ‘m\u00ec \u0103n li\u1ec1n’ n\u01a1i lu\u1ed3ng th\u1ef1c thi r\u1ea5t kh\u00f3 theo d\u00f5i.<\/p>\n

              Nh\u1eefng d\u1ea5u hi\u1ec7u b\u1ea1n n\u00ean d\u1eebng l\u1ea1i<\/h3>\n
                \n
              • Ki\u1ec3m tra ki\u1ec3u qu\u00e1 m\u1ee9c:<\/strong> N\u1ebfu m\u00e3 c\u1ee7a b\u1ea1n s\u1eed d\u1ee5ng `if (type == \u2018X\u2019)` b\u00ean trong m\u1ed9t kh\u1ed1i \u0111a h\u00ecnh, b\u1ea1n c\u00f3 th\u1ec3 \u0111\u00e3 l\u00e0m suy y\u1ebfu t\u00ednh \u0111a h\u00ecnh.<\/li>\n
              • Ph\u1ee9c t\u1ea1p so v\u1edbi R\u00f5 r\u00e0ng:<\/strong> N\u1ebfu m\u1ed9t th\u1ee7 t\u1ee5c \u0111\u01a1n gi\u1ea3n l\u00e0 \u0111\u1ee7, \u0111\u1eebng x\u00e2y d\u1ef1ng m\u1ed9t c\u1ea5u tr\u00fac ph\u00e2n c\u1ea5p giao di\u1ec7n.<\/li>\n
              • R\u00f2 r\u1ec9 tri\u1ec3n khai:<\/strong> N\u1ebfu l\u1edbp c\u01a1 s\u1edf bi\u1ebft qu\u00e1 nhi\u1ec1u v\u1ec1 c\u00e1c l\u1edbp con, th\u00ec s\u1ef1 tr\u1eebu t\u01b0\u1ee3ng \u0111ang b\u1ecb r\u00f2 r\u1ec9.<\/li>\n<\/ul>\n

                C\u00e1c Th\u1ef1c Ti\u1ec5n T\u1ed1t Nh\u1ea5t cho Vi\u1ec7c Tri\u1ec3n Khai \u2705<\/h2>\n

                \u0110\u1ec3 tri\u1ec3n khai \u0111a h\u00ecnh m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3, h\u00e3y tu\u00e2n theo c\u00e1c h\u01b0\u1edbng d\u1eabn sau.<\/p>\n

                1. \u01afa chu\u1ed9ng tr\u1eebu t\u01b0\u1ee3ng<\/h3>\n

                Thi\u1ebft k\u1ebf c\u00e1c l\u1edbp c\u1ee7a b\u1ea1n d\u1ef1a tr\u00ean h\u00e0nh vi m\u00e0 ch\u00fang cung c\u1ea5p, ch\u1ee9 kh\u00f4ng ph\u1ea3i d\u1eef li\u1ec7u ch\u00fang l\u01b0u tr\u1eef. C\u00e1c giao di\u1ec7n n\u00ean \u0111\u1ea1i di\u1ec7n cho vai tr\u00f2 (v\u00ed d\u1ee5: `\u0110\u1ecdc \u0111\u01b0\u1ee3c`, `Ghi \u0111\u01b0\u1ee3c`), ch\u1ee9 kh\u00f4ng ch\u1ec9 l\u00e0 danh m\u1ee5c (v\u00ed d\u1ee5: `T\u1ec7p`, `Lu\u1ed3ng M\u1ea1ng`).<\/p>\n

                2. Gi\u1eef c\u00e1c giao di\u1ec7n nh\u1ecf<\/h3>\n

                Tu\u00e2n theo Nguy\u00ean t\u1eafc T\u00e1ch bi\u1ec7t Giao di\u1ec7n. M\u1ed9t giao di\u1ec7n l\u1edbn bu\u1ed9c c\u00e1c tri\u1ec3n khai ph\u1ea3i bao g\u1ed3m c\u00e1c ph\u01b0\u01a1ng th\u1ee9c m\u00e0 ch\u00fang kh\u00f4ng c\u1ea7n. C\u00e1c giao di\u1ec7n nh\u1ecf, t\u1eadp trung gi\u00fap qu\u1ea3n l\u00fd \u0111a h\u00ecnh d\u1ec5 d\u00e0ng h\u01a1n.<\/p>\n

                3. S\u1eed d\u1ee5ng l\u1edbp tr\u1eebu t\u01b0\u1ee3ng cho m\u00e3 chung<\/h3>\n

                N\u1ebfu nhi\u1ec1u l\u1edbp con chia s\u1ebb chi ti\u1ebft tri\u1ec3n khai, m\u1ed9t l\u1edbp c\u01a1 s\u1edf tr\u1eebu t\u01b0\u1ee3ng c\u00f3 th\u1ec3 ch\u1ee9a logic \u0111\u00f3. N\u1ebfu ch\u00fang ch\u1ec9 chia s\u1ebb ch\u1eef k\u00fd, h\u00e3y s\u1eed d\u1ee5ng giao di\u1ec7n.<\/p>\n

                4. T\u00e0i li\u1ec7u h\u00f3a h\u00e0nh vi, ch\u1ee9 kh\u00f4ng ph\u1ea3i c\u01a1 ch\u1ebf<\/h3>\n

                Khi \u0111\u1ecbnh ngh\u0129a m\u1ed9t giao di\u1ec7n \u0111a h\u00ecnh, h\u00e3y t\u00e0i li\u1ec7u h\u00f3a h\u00e0nh vi mong \u0111\u1ee3i v\u00e0 c\u00e1c b\u1ea5t bi\u1ebfn. Kh\u00f4ng n\u00ean t\u00e0i li\u1ec7u h\u00f3a thu\u1eadt to\u00e1n n\u1ed9i b\u1ed9, v\u00ec \u0111\u00f3 l\u00e0 chi ti\u1ebft tri\u1ec3n khai.<\/p>\n

                V\u00ed d\u1ee5 Th\u1ef1c T\u1ebf: M\u1ed9t H\u1ec7 Th\u1ed1ng Th\u00f4ng B\u00e1o \ud83d\udce9<\/h2>\n

                H\u00e3y c\u00f9ng xem m\u1ed9t v\u00ed d\u1ee5 kh\u00e1i ni\u1ec7m v\u1ec1 h\u1ec7 th\u1ed1ng th\u00f4ng b\u00e1o. Ch\u00fang ta mu\u1ed1n g\u1eedi th\u00f4ng b\u00e1o qua Email, SMS v\u00e0 G\u1eedi \u0111\u1ea9y (Push).<\/p>\n

                Giao di\u1ec7n:<\/strong> `NotificationSender` v\u1edbi m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c `send(th\u00f4ng \u0111i\u1ec7p, ng\u01b0\u1eddi nh\u1eadn).`<\/p>\n

                C\u00e1c Tri\u1ec3n Khai:<\/strong><\/p>\n

                  \n
                • EmailSender:<\/strong> Tri\u1ec3n khai `send` \u0111\u1ec3 \u0111\u1ecbnh d\u1ea1ng email v\u00e0 \u0111\u1ecbnh tuy\u1ebfn qua m\u00e1y ch\u1ee7 th\u01b0 \u0111i\u1ec7n t\u1eed.<\/li>\n
                • SMSSender:<\/strong> Tri\u1ec3n khai `send` \u0111\u1ec3 \u0111\u1ecbnh d\u1ea1ng tin nh\u1eafn v\u0103n b\u1ea3n v\u00e0 \u0111\u1ecbnh tuy\u1ebfn qua c\u1ed5ng k\u1ebft n\u1ed1i.<\/li>\n
                • PushSender:<\/strong> Tri\u1ec3n khai `send` \u0111\u1ec3 g\u1eedi \u0111\u1ebfn m\u1ed9t m\u00e3 thi\u1ebft b\u1ecb (token).<\/li>\n<\/ul>\n

                  Kh\u00e1ch h\u00e0ng (Client):<\/strong> `NotificationManager` ch\u1ea5p nh\u1eadn m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng `NotificationSender`. N\u00f3 g\u1ecdi `send()` m\u00e0 kh\u00f4ng c\u1ea7n bi\u1ebft \u0111\u00f3 l\u00e0 email hay SMS.<\/p>\n

                  N\u1ebfu sau n\u00e0y ch\u00fang ta th\u00eam m\u1ed9t `SlackSender`, ch\u00fang ta ch\u1ec9 c\u1ea7n t\u1ea1o l\u1edbp m\u1edbi. `NotificationManager` s\u1ebd kh\u00f4ng thay \u0111\u1ed5i. \u0110\u00e2y ch\u00ednh l\u00e0 s\u1ee9c m\u1ea1nh c\u1ee7a \u0111a h\u00ecnh \u0111ang ho\u1ea1t \u0111\u1ed9ng. N\u00f3 c\u00f4 l\u1eadp t\u00e1c \u0111\u1ed9ng c\u1ee7a s\u1ef1 thay \u0111\u1ed5i.<\/p>\n

                  M\u1ed1i quan h\u1ec7 v\u1edbi K\u1ebf th\u1eeba v\u00e0 Tr\u1eebu t\u01b0\u1ee3ng \ud83d\udd04<\/h2>\n

                  \u0110a h\u00ecnh kh\u00f4ng t\u1ed3n t\u1ea1i trong kho\u1ea3ng tr\u1ed1ng. N\u00f3 ph\u1ee5 thu\u1ed9c v\u00e0o hai tr\u1ee5 c\u1ed9t kh\u00e1c c\u1ee7a thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng: k\u1ebf th\u1eeba v\u00e0 tr\u1eebu t\u01b0\u1ee3ng.<\/p>\n

                    \n
                  • K\u1ebf th\u1eeba:<\/strong> Cung c\u1ea5p c\u1ea5u tr\u00fac ph\u00e2n c\u1ea5p. N\u00f3 cho ph\u00e9p c\u00e1c l\u1edbp con k\u1ebf th\u1eeba tr\u1ea1ng th\u00e1i v\u00e0 h\u00e0nh vi t\u1eeb l\u1edbp cha.<\/li>\n
                  • Tr\u1eebu t\u01b0\u1ee3ng:<\/strong> Cung c\u1ea5p giao di\u1ec7n. N\u00f3 che gi\u1ea5u \u0111\u1ed9 ph\u1ee9c t\u1ea1p c\u1ee7a vi\u1ec7c tri\u1ec3n khai.<\/li>\n
                  • \u0110a h\u00ecnh:<\/strong> Cung c\u1ea5p t\u00ednh linh ho\u1ea1t. N\u00f3 cho ph\u00e9p giao di\u1ec7n ho\u1ea1t \u0111\u1ed9ng v\u1edbi b\u1ea5t k\u1ef3 tri\u1ec3n khai h\u1ee3p l\u1ec7 n\u00e0o.<\/li>\n<\/ul>\n

                    Kh\u00f4ng c\u00f3 tr\u1eebu t\u01b0\u1ee3ng, \u0111a h\u00ecnh ch\u1ec9 l\u00e0 k\u1ebf th\u1eeba. Kh\u00f4ng c\u00f3 k\u1ebf th\u1eeba, \u0111a h\u00ecnh ch\u1ec9 l\u00e0 g\u00f5 ki\u1ec3u chim v\u1ecbt. C\u00f9ng nhau, ch\u00fang t\u1ea1o th\u00e0nh m\u1ed9t khung v\u1eefng ch\u1eafc \u0111\u1ec3 qu\u1ea3n l\u00fd \u0111\u1ed9 ph\u1ee9c t\u1ea1p.<\/p>\n

                    Xem x\u00e9t v\u1ec1 hi\u1ec7u n\u0103ng \u26a1<\/h2>\n

                    Trong t\u00ednh to\u00e1n hi\u1ec7u n\u0103ng cao, chi ph\u00ed ph\u00e1t sinh t\u1eeb c\u00e1c l\u1eddi g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c \u1ea3o c\u00f3 th\u1ec3 \u0111\u00e1ng k\u1ec3. Tuy nhi\u00ean, trong ph\u1ea7n l\u1edbn ph\u00e1t tri\u1ec3n \u1ee9ng d\u1ee5ng, chi ph\u00ed n\u00e0y l\u00e0 kh\u00f4ng \u0111\u00e1ng k\u1ec3 so v\u1edbi c\u00e1c thao t\u00e1c nh\u1eadp\/xu\u1ea5t hay truy v\u1ea5n c\u01a1 s\u1edf d\u1eef li\u1ec7u.<\/p>\n

                    N\u1ebfu hi\u1ec7u n\u0103ng l\u00e0 y\u1ebfu t\u1ed1 then, h\u00e3y c\u00e2n nh\u1eafc:<\/p>\n

                      \n
                    • Nh\u00fang m\u00e3:<\/strong> M\u1ed9t s\u1ed1 tr\u00ecnh bi\u00ean d\u1ecbch c\u00f3 th\u1ec3 nh\u00fang c\u00e1c ph\u01b0\u01a1ng th\u1ee9c \u1ea3o n\u1ebfu ch\u00fang c\u00f3 th\u1ec3 x\u00e1c \u0111\u1ecbnh \u0111\u01b0\u1ee3c ki\u1ec3u th\u1ef1c t\u1ebf t\u1ea1i th\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch.<\/li>\n
                    • \u0110i\u1ec1u ph\u1ed1i t\u0129nh:<\/strong> S\u1eed d\u1ee5ng m\u1eabu ho\u1eb7c ki\u1ec3u chung \u1edf nh\u1eefng n\u01a1i m\u00e0 ki\u1ec3u d\u1eef li\u1ec7u \u0111\u01b0\u1ee3c bi\u1ebft r\u00f5 t\u1ea1i th\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch.<\/li>\n
                    • Ph\u00e2n t\u00edch hi\u1ec7u n\u0103ng:<\/strong> Lu\u00f4n \u0111o l\u01b0\u1eddng tr\u01b0\u1edbc khi t\u1ed1i \u01b0u h\u00f3a. T\u1ed1i \u01b0u h\u00f3a qu\u00e1 s\u1edbm th\u01b0\u1eddng l\u00e0m h\u1ecfng thi\u1ebft k\u1ebf.<\/li>\n<\/ul>\n

                      T\u00f3m t\u1eaft c\u00e1c h\u1ec7 qu\u1ea3 thi\u1ebft k\u1ebf \ud83d\udcdd<\/h2>\n

                      Vi\u1ec7c \u00e1p d\u1ee5ng \u0111a h\u00ecnh thay \u0111\u1ed5i c\u00e1ch b\u1ea1n suy ngh\u0129 v\u1ec1 ph\u1ea7n m\u1ec1m. N\u00f3 chuy\u1ec3n tr\u1ecdng t\u00e2m t\u1eeb \u201cc\u00e1ch l\u1edbp n\u00e0y ho\u1ea1t \u0111\u1ed9ng\u201d sang \u201cl\u1edbp n\u00e0y l\u00e0m g\u00ec\u201d. S\u1ef1 thay \u0111\u1ed5i n\u00e0y l\u00e0 n\u1ec1n t\u1ea3ng \u0111\u1ec3 x\u00e2y d\u1ef1ng c\u00e1c h\u1ec7 th\u1ed1ng t\u1ed3n t\u1ea1i qua th\u1eed th\u00e1ch c\u1ee7a th\u1eddi gian.<\/p>\n

                      B\u1eb1ng c\u00e1ch ch\u1ea5p nh\u1eadn \u0111a h\u00ecnh, b\u1ea1n t\u1ea1o ra m\u1ed9t h\u1ec7 th\u1ed1ng m\u00e0 c\u00e1c th\u00e0nh ph\u1ea7n \u0111\u01b0\u1ee3c li\u00ean k\u1ebft l\u1ecfng l\u1ebbo v\u00e0 c\u00f3 t\u00ednh g\u1eafn k\u1ebft cao. Nh\u1eefng thay \u0111\u1ed5i \u1edf m\u1ed9t khu v\u1ef1c s\u1ebd kh\u00f4ng lan r\u1ed9ng ti\u00eau c\u1ef1c qua to\u00e0n b\u1ed9 c\u01a1 s\u1edf m\u00e3 ngu\u1ed3n. C\u00e1c t\u00ednh n\u0103ng m\u1edbi c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u00eam v\u00e0o v\u1edbi r\u1ee7i ro t\u1ed1i thi\u1ec3u \u0111\u1ed1i v\u1edbi ch\u1ee9c n\u0103ng hi\u1ec7n c\u00f3.<\/p>\n

                      H\u00e0nh tr\u00ecnh t\u1eeb s\u1ef1 nh\u1ea7m l\u1eabn \u0111\u1ebfn s\u1ef1 r\u00f5 r\u00e0ng bao g\u1ed3m vi\u1ec7c hi\u1ec3u r\u1eb1ng \u0111a h\u00ecnh kh\u00f4ng ch\u1ec9 l\u00e0 m\u1ed9t t\u00ednh n\u0103ng ng\u00f4n ng\u1eef, m\u00e0 c\u00f2n l\u00e0 m\u1ed9t tri\u1ebft l\u00fd thi\u1ebft k\u1ebf. N\u00f3 khuy\u1ebfn kh\u00edch b\u1ea1n l\u00ean k\u1ebf ho\u1ea1ch cho s\u1ef1 thay \u0111\u1ed5i tr\u01b0\u1edbc khi n\u00f3 x\u1ea3y ra. N\u00f3 chu\u1ea9n b\u1ecb ki\u1ebfn tr\u00fac c\u1ee7a b\u1ea1n cho t\u01b0\u01a1ng lai.<\/p>\n

                      Suy ngh\u0129 cu\u1ed1i c\u00f9ng v\u1ec1 tri\u1ec3n khai \ud83d\ude80<\/h2>\n

                      B\u1eaft \u0111\u1ea7u nh\u1ecf. X\u00e1c \u0111\u1ecbnh nh\u1eefng khu v\u1ef1c trong c\u00e1c d\u1ef1 \u00e1n hi\u1ec7n t\u1ea1i c\u1ee7a b\u1ea1n m\u00e0 b\u1ea1n th\u01b0\u1eddng xuy\u00ean vi\u1ebft c\u00e1c kh\u1ed1i `if-else` l\u1eb7p l\u1ea1i d\u1ef1a tr\u00ean ki\u1ec3m tra ki\u1ec3u d\u1eef li\u1ec7u. T\u00e1i c\u1ea5u tr\u00fac ch\u00fang th\u00e0nh c\u00e1c c\u1ea5u tr\u00fac \u0111a h\u00ecnh. Quan s\u00e1t xem m\u00e3 ngu\u1ed3n tr\u1edf n\u00ean d\u1ec5 \u0111\u1ecdc v\u00e0 s\u1eeda \u0111\u1ed5i h\u01a1n nh\u01b0 th\u1ebf n\u00e0o.<\/p>\n

                      H\u00e3y nh\u1edb r\u1eb1ng kh\u00f4ng c\u00f4ng c\u1ee5 n\u00e0o l\u00e0 ho\u00e0n h\u1ea3o. S\u1eed d\u1ee5ng \u0111a h\u00ecnh \u1edf nh\u1eefng n\u01a1i ph\u00f9 h\u1ee3p v\u1edbi m\u00f4 h\u00ecnh mi\u1ec1n. \u0110\u1eebng \u00e9p bu\u1ed9c n\u00f3 khi logic th\u1ee7 t\u1ee5c r\u00f5 r\u00e0ng h\u01a1n. C\u00e2n b\u1eb1ng l\u00e0 ch\u00eca kh\u00f3a c\u1ee7a k\u1ef9 thu\u1eadt vi\u00ean chuy\u00ean nghi\u1ec7p.<\/p>\n

                      V\u1edbi vi\u1ec7c n\u1eafm v\u1eefng nh\u1eefng ki\u1ebfn th\u1ee9c c\u01a1 b\u1ea3n n\u00e0y, b\u1ea1n s\u1ebd t\u1ef1 tin x\u1eed l\u00fd c\u00e1c t\u01b0\u01a1ng t\u00e1c ph\u1ee9c t\u1ea1p gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng. S\u1ef1 nh\u1ea7m l\u1eabn s\u1ebd d\u1ea7n bi\u1ebfn m\u1ea5t, v\u00e0 c\u1ea5u tr\u00fac v\u1eabn r\u00f5 r\u00e0ng.<\/p>\n","protected":false},"excerpt":{"rendered":"

                      Hi\u1ec3u \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng \u0111\u00f2i h\u1ecfi ph\u1ea3i \u0111i qua nhi\u1ec1u kh\u00e1i ni\u1ec7m ph\u1ee9c t\u1ea1p, nh\u01b0ng \u00edt kh\u00e1i ni\u1ec7m n\u00e0o b\u1ecb hi\u1ec3u nh\u1ea7m nhi\u1ec1u nh\u01b0 \u0111a h\u00ecnh. Th\u01b0\u1eddng…<\/p>\n","protected":false},"author":1,"featured_media":1959,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_title":"C\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh m\u00e0 kh\u00f4ng g\u00e2y nh\u1ea7m l\u1eabn | H\u01b0\u1edbng d\u1eabn OOAD","_yoast_wpseo_metadesc":"H\u1ecdc c\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. C\u00e1c \u0111\u1ecbnh ngh\u0129a r\u00f5 r\u00e0ng, so s\u00e1nh th\u1eddi \u0111i\u1ec3m ch\u1ea1y v\u00e0 th\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch, c\u00f9ng c\u00e1c th\u1ef1c h\u00e0nh t\u1ed1t nh\u1ea5t cho ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m linh ho\u1ea1t.","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[94],"tags":[87,93],"class_list":["post-1958","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-object-oriented-analysis-and-design","tag-academic","tag-object-oriented-analysis-and-design"],"yoast_head":"\nC\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh m\u00e0 kh\u00f4ng g\u00e2y nh\u1ea7m l\u1eabn | H\u01b0\u1edbng d\u1eabn OOAD<\/title>\n<meta name=\"description\" content=\"H\u1ecdc c\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. C\u00e1c \u0111\u1ecbnh ngh\u0129a r\u00f5 r\u00e0ng, so s\u00e1nh th\u1eddi \u0111i\u1ec3m ch\u1ea1y v\u00e0 th\u1eddi \u0111i\u1ec3m bi\u00ean d\u1ecbch, c\u00f9ng c\u00e1c th\u1ef1c h\u00e0nh t\u1ed1t nh\u1ea5t cho ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m linh ho\u1ea1t.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.tech-posts.com\/vi\/polymorphism-basics-without-confusion\/\" \/>\n<meta property=\"og:locale\" content=\"vi_VN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"C\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh m\u00e0 kh\u00f4ng g\u00e2y nh\u1ea7m l\u1eabn | H\u01b0\u1edbng d\u1eabn OOAD\" \/>\n<meta property=\"og:description\" content=\"H\u1ecdc c\u00e1c kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n v\u1ec1 \u0111a h\u00ecnh trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. 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