{"id":3456,"date":"2026-03-26T14:19:54","date_gmt":"2026-03-26T06:19:54","guid":{"rendered":"https:\/\/www.go2posts.com\/vi\/applying-observer-pattern-loose-coupling\/"},"modified":"2026-03-26T14:19:54","modified_gmt":"2026-03-26T06:19:54","slug":"applying-observer-pattern-loose-coupling","status":"publish","type":"post","link":"https:\/\/www.go2posts.com\/vi\/applying-observer-pattern-loose-coupling\/","title":{"rendered":"H\u01b0\u1edbng d\u1eabn OOAD: \u00c1p d\u1ee5ng M\u1eabu Quan s\u00e1t \u0111\u1ec3 \u0111\u1ea1t\u8026 k\u1ebft l\u1ecfng l\u1ebbo"},"content":{"rendered":"

Trong b\u1ed1i c\u1ea3nh Ph\u00e2n t\u00edch v\u00e0 Thi\u1ebft k\u1ebf H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOAD), m\u1ed9t trong nh\u1eefng th\u00e1ch th\u1ee9c dai d\u1eb3ng nh\u1ea5t m\u00e0 c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n ph\u1ea3i \u0111\u1ed1i m\u1eb7t l\u00e0 qu\u1ea3n l\u00fd c\u00e1c m\u1ed1i ph\u1ee5 thu\u1ed9c gi\u1eefa c\u00e1c th\u00e0nh ph\u1ea7n. Khi c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng bi\u1ebft qu\u00e1 nhi\u1ec1u v\u1ec1 nhau, h\u1ec7 th\u1ed1ng tr\u1edf n\u00ean c\u1ee9ng nh\u1eafc, kh\u00f3 ki\u1ec3m th\u1eed v\u00e0 d\u1ec5 d\u1eabn \u0111\u1ebfn c\u00e1c l\u1ed7i lan truy\u1ec1n. \u0110\u1ec3 gi\u1ea3i quy\u1ebft s\u1ef1 b\u1ea5t \u1ed5n c\u1ea5u tr\u00fac n\u00e0y, m\u1eabuM\u1eabu Quan s\u00e1t<\/strong> n\u1ed5i b\u1eadt nh\u01b0 m\u1ed9t m\u1eabu thi\u1ebft k\u1ebf h\u00e0nh vi c\u01a1 b\u1ea3n. N\u00f3 thi\u1ebft l\u1eadp c\u01a1 ch\u1ebf \u0111\u0103ng k\u00fd cho ph\u00e9p c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng giao ti\u1ebfp m\u00e0 kh\u00f4ng c\u1ea7n t\u1ea1o ra c\u00e1c li\u00ean k\u1ebft tr\u1ef1c ti\u1ebfp, \u0111\u01b0\u1ee3c m\u00e3 h\u00f3a c\u1ee9ng. H\u01b0\u1edbng d\u1eabn n\u00e0y kh\u00e1m ph\u00e1 v\u1ec1 c\u01a1 ch\u1ebf, tri\u1ec3n khai v\u00e0 \u1ee9ng d\u1ee5ng chi\u1ebfn l\u01b0\u1ee3c c\u1ee7a M\u1eabu Quan s\u00e1t \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c s\u1ef1\u8026 k\u1ebft l\u1ecfng l\u1ebbo th\u1ef1c s\u1ef1 trong ki\u1ebfn tr\u00fac ph\u1ea7n m\u1ec1m c\u1ee7a b\u1ea1n.<\/p>\n

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\"Child-style<\/figure>\n<\/div>\n

\ud83e\udde9 Hi\u1ec3u v\u1ec1 M\u1eabu Quan s\u00e1t<\/h2>\n

\u1ede c\u1ed1t l\u00f5i, M\u1eabu Quan s\u00e1t \u0111\u1ecbnh ngh\u0129a m\u1ed1i quan h\u1ec7 m\u1ed9t-nhi\u1ec1u gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng. Khi m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 Ch\u1ee7 th\u1ec3, thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i, t\u1ea5t c\u1ea3 c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ph\u1ee5 thu\u1ed9c c\u1ee7a n\u00f3, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 Ng\u01b0\u1eddi quan s\u00e1t, s\u1ebd \u0111\u01b0\u1ee3c th\u00f4ng b\u00e1o v\u00e0 c\u1eadp nh\u1eadt t\u1ef1 \u0111\u1ed9ng. M\u1ed1i quan h\u1ec7 n\u00e0y l\u00e0 \u0111\u1ed9ng, ngh\u0129a l\u00e0 c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng c\u00f3 th\u1ec3 \u0111\u0103ng k\u00fd ho\u1eb7c h\u1ee7y \u0111\u0103ng k\u00fd m\u1ed1i quan h\u1ec7 n\u00e0y t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1y. M\u1ee5c ti\u00eau ch\u00ednh l\u00e0 t\u00e1ch r\u1eddi Ch\u1ee7 th\u1ec3 kh\u1ecfi c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t. Ch\u1ee7 th\u1ec3 kh\u00f4ng c\u1ea7n bi\u1ebft l\u1edbp c\u1ee5 th\u1ec3 c\u1ee7a c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t; n\u00f3 ch\u1ec9 c\u1ea7n bi\u1ebft r\u1eb1ng ch\u00fang tri\u1ec3n khai m\u1ed9t giao di\u1ec7n c\u1ee5 th\u1ec3.<\/p>\n

M\u1eabu n\u00e0y \u0111\u1eb7c bi\u1ec7t c\u00f3 gi\u00e1 tr\u1ecb trong c\u00e1c h\u1ec7 th\u1ed1ng m\u00e0 tr\u1ea1ng th\u00e1i c\u1ee7a m\u1ed9t th\u00e0nh ph\u1ea7n k\u00edch ho\u1ea1t c\u00e1c h\u00e0nh \u0111\u1ed9ng \u1edf c\u00e1c ph\u1ea7n kh\u00e1c c\u1ee7a h\u1ec7 th\u1ed1ng. V\u00ed d\u1ee5, h\u00e3y xem x\u00e9t m\u1ed9t lu\u1ed3ng x\u1eed l\u00fd d\u1eef li\u1ec7u n\u01a1i m\u1ed9t thay \u0111\u1ed5i trong b\u1ea3n ghi ngu\u1ed3n ph\u1ea3i k\u00edch ho\u1ea1t c\u1eadp nh\u1eadt trong b\u1ed9 nh\u1edb \u0111\u1ec7m, t\u1ec7p nh\u1eadt k\u00fd v\u00e0 giao di\u1ec7n ng\u01b0\u1eddi d\u00f9ng. Kh\u00f4ng c\u00f3 m\u1eabu n\u00e0y, b\u1ea3n ghi ngu\u1ed3n s\u1ebd c\u1ea7n gi\u1eef tham chi\u1ebfu \u0111\u1ebfn b\u1ed9 nh\u1edb \u0111\u1ec7m, tr\u00ecnh ghi nh\u1eadt k\u00fd v\u00e0 logic hi\u1ec3n th\u1ecb. \u0110i\u1ec1u n\u00e0y t\u1ea1o ra s\u1ef1\u8026 k\u1ebft ch\u1eb7t ch\u1ebd. B\u1eb1ng c\u00e1ch gi\u1edbi thi\u1ec7u M\u1eabu Quan s\u00e1t, b\u1ea3n ghi ngu\u1ed3n ch\u1ec9 c\u1ea7n th\u00f4ng b\u00e1o \u0111\u1ebfn m\u1ed9t giao di\u1ec7n, v\u00e0 c\u00e1c tri\u1ec3n khai c\u1ee5 th\u1ec3 s\u1ebd x\u1eed l\u00fd logic th\u00f4ng b\u00e1o.<\/p>\n

\ud83d\udd27 C\u00e1c th\u00e0nh ph\u1ea7n ch\u00ednh c\u1ee7a m\u1eabu<\/h2>\n

\u0110\u1ec3 tri\u1ec3n khai m\u1eabu n\u00e0y m\u1ed9t c\u00e1ch hi\u1ec7u qu\u1ea3, b\u1ea1n ph\u1ea3i x\u00e1c \u0111\u1ecbnh v\u00e0 \u0111\u1ecbnh ngh\u0129a r\u00f5 c\u00e1c vai tr\u00f2 c\u1ee5 th\u1ec3 trong ki\u1ebfn tr\u00fac. C\u00e1c vai tr\u00f2 n\u00e0y \u0111\u1ea3m b\u1ea3o nguy\u00ean t\u1eafc t\u00e1ch bi\u1ec7t tr\u00e1ch nhi\u1ec7m v\u1eabn \u0111\u01b0\u1ee3c duy tr\u00ec.<\/p>\n

    \n
  • Ch\u1ee7 th\u1ec3:<\/strong> \u0110\u00e2y l\u00e0 \u0111\u1ed1i t\u01b0\u1ee3ng \u0111ang \u0111\u01b0\u1ee3c quan s\u00e1t. N\u00f3 duy tr\u00ec danh s\u00e1ch c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t v\u00e0 cung c\u1ea5p c\u00e1c ph\u01b0\u01a1ng th\u1ee9c \u0111\u1ec3 g\u1eafn, th\u00e1o g\u1ee1 v\u00e0 th\u00f4ng b\u00e1o cho ch\u00fang. Ch\u1ee7 th\u1ec3 ch\u1ecbu tr\u00e1ch nhi\u1ec7m ph\u00e1t s\u00f3ng c\u00e1c thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i.<\/li>\n
  • Ng\u01b0\u1eddi quan s\u00e1t:<\/strong> \u0110\u00e2y l\u00e0 giao di\u1ec7n ho\u1eb7c l\u1edbp tr\u1eebu t\u01b0\u1ee3ng \u0111\u1ecbnh ngh\u0129a ph\u01b0\u01a1ng th\u1ee9c c\u1eadp nh\u1eadt. M\u1ecdi l\u1edbp mu\u1ed1n nh\u1eadn th\u00f4ng b\u00e1o \u0111\u1ec1u ph\u1ea3i tri\u1ec3n khai giao di\u1ec7n n\u00e0y. N\u00f3 \u0111\u1ea3m b\u1ea3o m\u1ed9t h\u1ee3p \u0111\u1ed3ng nh\u1ea5t qu\u00e1n cho vi\u1ec7c nh\u1eadn c\u1eadp nh\u1eadt.<\/li>\n
  • Ch\u1ee7 th\u1ec3 c\u1ee5 th\u1ec3:<\/strong> \u0110\u00e2y l\u00e0 tri\u1ec3n khai th\u1ef1c t\u1ebf c\u1ee7a Ch\u1ee7 th\u1ec3. N\u00f3 l\u01b0u tr\u1eef tr\u1ea1ng th\u00e1i v\u00e0 k\u00edch ho\u1ea1t logic th\u00f4ng b\u00e1o khi tr\u1ea1ng th\u00e1i \u0111\u00f3 thay \u0111\u1ed5i.<\/li>\n
  • Ng\u01b0\u1eddi quan s\u00e1t c\u1ee5 th\u1ec3:<\/strong> \u0110\u00e2y l\u00e0 c\u00e1c tri\u1ec3n khai c\u1ee5 th\u1ec3 c\u1ee7a giao di\u1ec7n Ng\u01b0\u1eddi quan s\u00e1t. Ch\u00fang ch\u1ee9a logic \u0111\u1ec3 ph\u1ea3n \u1ee9ng v\u1edbi th\u00f4ng b\u00e1o t\u1eeb Ch\u1ee7 th\u1ec3.<\/li>\n
  • Kh\u00e1ch h\u00e0ng:<\/strong> \u0110\u00e2y l\u00e0 ph\u1ea7n c\u1ee7a \u1ee9ng d\u1ee5ng t\u1ea1o ra c\u00e1c Ch\u1ee7 th\u1ec3 c\u1ee5 th\u1ec3 v\u00e0 Ng\u01b0\u1eddi quan s\u00e1t c\u1ee5 th\u1ec3, \u0111\u1ed3ng th\u1eddi thi\u1ebft l\u1eadp m\u1ed1i quan h\u1ec7 gi\u1eefa ch\u00fang.<\/li>\n<\/ul>\n

    B\u1eb1ng c\u00e1ch tu\u00e2n th\u1ee7 nghi\u00eam ng\u1eb7t c\u00e1c vai tr\u00f2 n\u00e0y, b\u1ea1n \u0111\u1ea3m b\u1ea3o r\u1eb1ng Ch\u1ee7 th\u1ec3 kh\u00f4ng bao gi\u1edd ph\u1ee5 thu\u1ed9c v\u00e0o c\u00e1c chi ti\u1ebft n\u1ed9i b\u1ed9 c\u1ee7a Ng\u01b0\u1eddi quan s\u00e1t. N\u00f3 ch\u1ec9 ph\u1ee5 thu\u1ed9c v\u00e0o giao di\u1ec7n. \u0110\u00e2y ch\u00ednh l\u00e0 b\u1ea3n ch\u1ea5t c\u1ee7a t\u00e1ch bi\u1ec7t giao di\u1ec7n v\u00e0 \u0111\u1ea3o ng\u01b0\u1ee3c ph\u1ee5 thu\u1ed9c \u0111ang \u0111\u01b0\u1ee3c th\u1ef1c thi.<\/p>\n

    \ud83c\udf09 C\u01a1 ch\u1ebf \u0111\u1ec3 \u0111\u1ea1t\u8026 k\u1ebft l\u1ecfng l\u1ebbo<\/h2>\n

    L\u1ee3i th\u1ebf ch\u00ednh c\u1ee7a m\u1eabu n\u00e0y l\u00e0 gi\u1ea3m s\u1ef1\u8026 k\u1ebft. Trong thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng truy\u1ec1n th\u1ed1ng, \u0110\u1ed1i t\u01b0\u1ee3ng A c\u00f3 th\u1ec3 tr\u1ef1c ti\u1ebfp kh\u1edfi t\u1ea1o \u0110\u1ed1i t\u01b0\u1ee3ng B \u0111\u1ec3 th\u1ef1c hi\u1ec7n m\u1ed9t h\u00e0nh \u0111\u1ed9ng. N\u1ebfu \u0110\u1ed1i t\u01b0\u1ee3ng B thay \u0111\u1ed5i, \u0110\u1ed1i t\u01b0\u1ee3ng A ph\u1ea3i \u0111\u01b0\u1ee3c bi\u00ean d\u1ecbch l\u1ea1i ho\u1eb7c ch\u1ec9nh s\u1eeda l\u1ea1i. V\u1edbi M\u1eabu Quan s\u00e1t, \u0110\u1ed1i t\u01b0\u1ee3ng A (Ch\u1ee7 th\u1ec3) t\u01b0\u01a1ng t\u00e1c v\u1edbi m\u1ed9t danh s\u00e1ch c\u00e1c giao di\u1ec7n. \u0110\u1ed1i t\u01b0\u1ee3ng B (Ng\u01b0\u1eddi quan s\u00e1t) tri\u1ec3n khai giao di\u1ec7n \u0111\u00f3.<\/p>\n

    H\u00e3y xem x\u00e9t c\u00e1c t\u00ecnh hu\u1ed1ng sau \u0111\u00e2y li\u00ean quan \u0111\u1ebfn s\u1ef1\u8026 k\u1ebft:<\/p>\n

      \n
    • \u8026 k\u1ebft ch\u1eb7t ch\u1ebd:<\/strong> Ch\u1ee7 th\u1ec3 gi\u1eef tham chi\u1ebfu c\u1ee5 th\u1ec3 \u0111\u1ebfn Ng\u01b0\u1eddi quan s\u00e1t. Nh\u1eefng thay \u0111\u1ed5i trong l\u1edbp Ng\u01b0\u1eddi quan s\u00e1t y\u00eau c\u1ea7u thay \u0111\u1ed5i trong l\u1edbp Ch\u1ee7 th\u1ec3.<\/li>\n
    • \u8026 k\u1ebft l\u1ecfng l\u1ebbo:<\/strong> Ch\u1ee7 th\u1ec3 gi\u1eef tham chi\u1ebfu \u0111\u1ebfn giao di\u1ec7n Ng\u01b0\u1eddi quan s\u00e1t. Ng\u01b0\u1eddi quan s\u00e1t c\u1ee5 th\u1ec3 \u0111\u01b0\u1ee3c \u0111\u0103ng k\u00fd t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1y. Ch\u1ee7 th\u1ec3 v\u1eabn kh\u00f4ng bi\u1ebft logic c\u1ee5 th\u1ec3 c\u1ee7a Ng\u01b0\u1eddi quan s\u00e1t c\u1ee5 th\u1ec3.<\/li>\n<\/ul>\n

      Vi\u1ec7c t\u00e1ch r\u1eddi n\u00e0y cho ph\u00e9p linh ho\u1ea1t h\u01a1n. B\u1ea1n c\u00f3 th\u1ec3 th\u00eam ng\u01b0\u1eddi quan s\u00e1t m\u1edbi v\u00e0o m\u1ed9t ch\u1ee7 th\u1ec3 m\u00e0 kh\u00f4ng c\u1ea7n s\u1eeda \u0111\u1ed5i m\u00e3 ngu\u1ed3n c\u1ee7a ch\u1ee7 th\u1ec3. B\u1ea1n c\u00f3 th\u1ec3 lo\u1ea1i b\u1ecf ng\u01b0\u1eddi quan s\u00e1t m\u1ed9t c\u00e1ch \u0111\u1ed9ng. \u0110i\u1ec1u n\u00e0y ph\u00f9 h\u1ee3p v\u1edbi Nguy\u00ean t\u1eafc M\u1edf\/\u0110\u00f3ng, v\u1ed1n n\u00eau r\u1eb1ng c\u00e1c th\u1ef1c th\u1ec3 ph\u1ea7n m\u1ec1m n\u00ean \u0111\u01b0\u1ee3c m\u1edf r\u1ed9ng nh\u01b0ng \u0111\u00f3ng l\u1ea1i v\u1edbi vi\u1ec7c s\u1eeda \u0111\u1ed5i.<\/p>\n

      \ud83d\udee0\ufe0f Chi\u1ebfn l\u01b0\u1ee3c tri\u1ec3n khai<\/h2>\n

      Tri\u1ec3n khai M\u1eabu Quan s\u00e1t \u0111\u00f2i h\u1ecfi s\u1ef1 ch\u00fa \u00fd c\u1ea9n th\u1eadn \u0111\u1ebfn v\u00f2ng \u0111\u1eddi c\u1ee7a vi\u1ec7c \u0111\u0103ng k\u00fd. Quy tr\u00ecnh n\u00f3i chung tu\u00e2n theo c\u00e1c b\u01b0\u1edbc sau:<\/p>\n

        \n
      1. X\u00e1c \u0111\u1ecbnh giao di\u1ec7n:<\/strong> T\u1ea1o m\u1ed9t giao di\u1ec7n chung cho Ng\u01b0\u1eddi quan s\u00e1t. Giao di\u1ec7n n\u00e0y n\u00ean ch\u1ee9a m\u1ed9t ph\u01b0\u01a1ng th\u1ee9cc\u1eadp nh\u1eadt<\/code> ph\u01b0\u01a1ng th\u1ee9c ch\u1ea5p nh\u1eadn tr\u1ea1ng th\u00e1i ho\u1eb7c m\u1ed9t tham chi\u1ebfu \u0111\u1ebfn \u0110\u1ed1i t\u01b0\u1ee3ng.<\/li>\n
      2. Th\u1ef1c hi\u1ec7n \u0110\u1ed1i t\u01b0\u1ee3ng:<\/strong> T\u1ea1o l\u1edbp \u0110\u1ed1i t\u01b0\u1ee3ng v\u1edbi m\u1ed9t b\u1ed9 l\u01b0u tr\u1eef \u0111\u1ec3 l\u01b0u c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t. Th\u1ef1c hi\u1ec7nghi nh\u1eadn<\/code>, th\u00e1o g\u1ee1<\/code>, v\u00e0th\u00f4ng b\u00e1o<\/code> ph\u01b0\u01a1ng th\u1ee9c.<\/li>\n
      3. Th\u1ef1c hi\u1ec7n c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t c\u1ee5 th\u1ec3:<\/strong> T\u1ea1o c\u00e1c l\u1edbp tri\u1ec3n khai giao di\u1ec7n Ng\u01b0\u1eddi quan s\u00e1t. B\u00ean trong ph\u01b0\u01a1ng th\u1ee9cc\u1eadp nh\u1eadt<\/code> ph\u01b0\u01a1ng th\u1ee9c, x\u00e1c \u0111\u1ecbnh logic c\u1ee5 th\u1ec3 c\u1ea7n thi\u1ebft cho lo\u1ea1i Ng\u01b0\u1eddi quan s\u00e1t \u0111\u00f3.<\/li>\n
      4. Thi\u1ebft l\u1eadp m\u1ed1i quan h\u1ec7:<\/strong> Trong m\u00e3 Client, kh\u1edfi t\u1ea1o \u0110\u1ed1i t\u01b0\u1ee3ng v\u00e0 c\u00e1c Ng\u01b0\u1eddi quan s\u00e1t. G\u1ecdi ph\u01b0\u01a1ng th\u1ee9c ghi nh\u1eadn tr\u00ean \u0110\u1ed1i t\u01b0\u1ee3ng \u0111\u1ec3 k\u1ebft n\u1ed1i ch\u00fang.<\/li>\n
      5. K\u00edch ho\u1ea1t c\u1eadp nh\u1eadt:<\/strong> Khi tr\u1ea1ng th\u00e1i c\u1ee7a \u0110\u1ed1i t\u01b0\u1ee3ng thay \u0111\u1ed5i, g\u1ecdi ph\u01b0\u01a1ng th\u1ee9c th\u00f4ng b\u00e1o. \u0110\u1ed1i t\u01b0\u1ee3ng duy\u1ec7t qua danh s\u00e1ch Ng\u01b0\u1eddi quan s\u00e1t v\u00e0 g\u1ecdi c\u00e1c ph\u01b0\u01a1ng th\u1ee9c c\u1eadp nh\u1eadt c\u1ee7a h\u1ecd.<\/li>\n<\/ol>\n

        \u0110i\u1ec1u quan tr\u1ecdng l\u00e0 qu\u00e1 tr\u00ecnh th\u00f4ng b\u00e1o kh\u00f4ng \u0111\u01b0\u1ee3c ch\u1eb7n \u0110\u1ed1i t\u01b0\u1ee3ng v\u00f4 th\u1eddi h\u1ea1n. N\u1ebfu m\u1ed9t Ng\u01b0\u1eddi quan s\u00e1t m\u1ea5t nhi\u1ec1u th\u1eddi gian \u0111\u1ec3 x\u1eed l\u00fd c\u1eadp nh\u1eadt, \u0111i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 l\u00e0m gi\u1ea3m hi\u1ec7u su\u1ea5t c\u1ee7a \u0110\u1ed1i t\u01b0\u1ee3ng. Do \u0111\u00f3, v\u00f2ng l\u1eb7p th\u00f4ng b\u00e1o c\u1ea7n ph\u1ea3i hi\u1ec7u qu\u1ea3.<\/p>\n

        \ud83d\udcca \u01afu \u0111i\u1ec3m v\u00e0 Nh\u01b0\u1ee3c \u0111i\u1ec3m<\/h2>\n

        Gi\u1ed1ng nh\u01b0 t\u1ea5t c\u1ea3 c\u00e1c m\u1eabu thi\u1ebft k\u1ebf, M\u1eabu Ng\u01b0\u1eddi quan s\u00e1t c\u00f3 nh\u1eefng \u0111i\u1ec3m \u0111\u00e1nh \u0111\u1ed5i. Hi\u1ec3u r\u00f5 nh\u1eefng \u0111i\u1ec1u n\u00e0y s\u1ebd gi\u00fap quy\u1ebft \u0111\u1ecbnh khi n\u00e0o n\u00ean \u00e1p d\u1ee5ng n\u00f3.<\/p>\n\n\n\n\n\n\n\n\n
        Kh\u00eda c\u1ea1nh<\/strong><\/th>\nChi ti\u1ebft<\/strong><\/th>\n<\/tr>\n
        K\u1ebft n\u1ed1i l\u1ecfng l\u1ebbo<\/strong><\/td>\n\u0110\u1ed1i t\u01b0\u1ee3ng v\u00e0 Ng\u01b0\u1eddi quan s\u00e1t l\u00e0 \u0111\u1ed9c l\u1eadp. B\u1ea1n c\u00f3 th\u1ec3 thay \u0111\u1ed5i m\u1ed9t b\u00ean m\u00e0 kh\u00f4ng \u1ea3nh h\u01b0\u1edfng \u0111\u00e1ng k\u1ec3 \u0111\u1ebfn b\u00ean kia.<\/td>\n<\/tr>\n
        M\u1ed1i quan h\u1ec7 \u0111\u1ed9ng<\/strong><\/td>\nC\u00e1c Ng\u01b0\u1eddi quan s\u00e1t c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c th\u00eam ho\u1eb7c x\u00f3a t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1y m\u00e0 kh\u00f4ng c\u1ea7n bi\u00ean d\u1ecbch l\u1ea1i \u0110\u1ed1i t\u01b0\u1ee3ng.<\/td>\n<\/tr>\n
        H\u1ed7 tr\u1ee3 ph\u00e1t s\u00f3ng<\/strong><\/td>\nM\u1ed9t thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i duy nh\u1ea5t c\u00f3 th\u1ec3 k\u00edch ho\u1ea1t c\u1eadp nh\u1eadt \u0111\u1ed3ng th\u1eddi tr\u00ean nhi\u1ec1u \u0111\u1ed1i t\u01b0\u1ee3ng.<\/td>\n<\/tr>\n
        C\u1eadp nh\u1eadt kh\u00f4ng th\u1ec3 d\u1ef1 \u0111o\u00e1n \u0111\u01b0\u1ee3c<\/strong><\/td>\nTh\u1ee9 t\u1ef1 m\u00e0 c\u00e1c quan s\u00e1t vi\u00ean nh\u1eadn th\u00f4ng b\u00e1o kh\u00f4ng \u0111\u01b0\u1ee3c \u0111\u1ea3m b\u1ea3o. \u0110i\u1ec1u n\u00e0y c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn tr\u1ea1ng th\u00e1i kh\u00f4ng nh\u1ea5t qu\u00e1n n\u1ebfu c\u00e1c quan s\u00e1t vi\u00ean ph\u1ee5 thu\u1ed9c l\u1eabn nhau.<\/td>\n<\/tr>\n
        Chi ph\u00ed hi\u1ec7u su\u1ea5t<\/strong><\/td>\nTh\u00f4ng b\u00e1o cho m\u1ed9t l\u01b0\u1ee3ng l\u1edbn quan s\u00e1t vi\u00ean c\u00f3 th\u1ec3 t\u1ed1n k\u00e9m n\u1ebfu logic c\u1eadp nh\u1eadt ph\u1ee9c t\u1ea1p.<\/td>\n<\/tr>\n
        R\u00f2 r\u1ec9 b\u1ed9 nh\u1edb<\/strong><\/td>\nN\u1ebfu c\u00e1c quan s\u00e1t vi\u00ean kh\u00f4ng \u0111\u01b0\u1ee3c ng\u1eaft k\u1ebft n\u1ed1i \u0111\u00fang c\u00e1ch, ch\u00fang c\u00f3 th\u1ec3 v\u1eabn t\u1ed3n t\u1ea1i trong b\u1ed9 nh\u1edb ngay c\u1ea3 khi ch\u00fang kh\u00f4ng c\u00f2n c\u1ea7n thi\u1ebft.<\/td>\n<\/tr>\n<\/table>\n

        \ud83d\udcc2 C\u00e1c t\u00ecnh hu\u1ed1ng \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf<\/h2>\n

        M\u1eb7c d\u00f9 l\u00fd thuy\u1ebft l\u00e0 h\u1ee3p l\u00fd, nh\u01b0ng vi\u1ec7c \u00e1p d\u1ee5ng th\u1ef1c t\u1ebf \u0111\u00f2i h\u1ecfi b\u1ed1i c\u1ea3nh c\u1ee5 th\u1ec3. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 nh\u1eefng t\u00ecnh hu\u1ed1ng c\u1ee5 th\u1ec3 m\u00e0 M\u1eabu Quan s\u00e1t mang l\u1ea1i gi\u00e1 tr\u1ecb l\u1edbn.<\/p>\n

        1. C\u1eadp nh\u1eadt giao di\u1ec7n ng\u01b0\u1eddi d\u00f9ng<\/h3>\n

        Trong c\u00e1c giao di\u1ec7n ng\u01b0\u1eddi d\u00f9ng \u0111\u1ed3 h\u1ecda, c\u00e1c m\u00f4 h\u00ecnh d\u1eef li\u1ec7u th\u01b0\u1eddng c\u1ea7n ph\u1ea3n \u00e1nh c\u00e1c thay \u0111\u1ed5i tr\u00ean giao di\u1ec7n. N\u1ebfu ng\u01b0\u1eddi d\u00f9ng ch\u1ec9nh s\u1eeda m\u1ed9t gi\u00e1 tr\u1ecb trong h\u1ed9p v\u0103n b\u1ea3n, nh\u00e3n hi\u1ec3n th\u1ecb gi\u00e1 tr\u1ecb \u0111\u00f3 ph\u1ea3i \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt. N\u1ebfu nh\u00e3n, tr\u1ea1ng th\u00e1i n\u00fat b\u1ea5m v\u00e0 th\u00f4ng b\u00e1o x\u00e1c th\u1ef1c \u0111\u1ec1u c\u1ea7n \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt, M\u1eabu Quan s\u00e1t cho ph\u00e9p m\u00f4 h\u00ecnh ph\u00e1t s\u00f3ng thay \u0111\u1ed5i m\u00e0 kh\u00f4ng c\u1ea7n bi\u1ebft \u0111\u1ebfn c\u00e1c th\u00e0nh ph\u1ea7n giao di\u1ec7n ng\u01b0\u1eddi d\u00f9ng.<\/p>\n

        2. H\u1ec7 th\u1ed1ng d\u1ef1a tr\u00ean s\u1ef1 ki\u1ec7n<\/h3>\n

        C\u00e1c h\u1ec7 th\u1ed1ng x\u1eed l\u00fd s\u1ef1 ki\u1ec7n, ch\u1eb3ng h\u1ea1n nh\u01b0 ghi nh\u1eadt k\u00fd ho\u1eb7c gi\u00e1m s\u00e1t, h\u01b0\u1edfng l\u1ee3i t\u1eeb m\u1eabu n\u00e0y. Khi m\u1ed9t s\u1ef1 ki\u1ec7n c\u1ee5 th\u1ec3 x\u1ea3y ra (v\u00ed d\u1ee5: vi ph\u1ea1m an ninh), nhi\u1ec1u h\u1ec7 th\u1ed1ng con c\u00f3 th\u1ec3 c\u1ea7n ph\u1ea3n \u1ee9ng (v\u00ed d\u1ee5: g\u1eedi c\u1ea3nh b\u00e1o, ghi l\u1ea1i s\u1ef1 c\u1ed1, kh\u00f3a t\u00e0i kho\u1ea3n). M\u1eabu Quan s\u00e1t \u0111\u1ea3m b\u1ea3o c\u00e1c ph\u1ea3n \u1ee9ng n\u00e0y x\u1ea3y ra t\u1ef1 \u0111\u1ed9ng m\u00e0 kh\u00f4ng c\u1ea7n module b\u1ea3o m\u1eadt ghi c\u1ee9ng logic cho t\u1eebng ph\u1ea3n \u1ee9ng.<\/p>\n

        3. \u0110\u1ed3ng b\u1ed9 h\u00f3a d\u1eef li\u1ec7u<\/h3>\n

        Trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n, t\u00ednh nh\u1ea5t qu\u00e1n d\u1eef li\u1ec7u l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t. N\u1ebfu c\u01a1 s\u1edf d\u1eef li\u1ec7u ch\u00ednh \u0111\u01b0\u1ee3c c\u1eadp nh\u1eadt, c\u00e1c b\u1ed9 nh\u1edb \u0111\u1ec7m ph\u1ee5 ho\u1eb7c b\u1ea3n sao \u0111\u1ecdc c\u1ea7n \u0111\u01b0\u1ee3c l\u00e0m m\u1edbi. C\u00e1c quan s\u00e1t vi\u00ean c\u00f3 th\u1ec3 l\u1eafng nghe s\u1ef1 ki\u1ec7n commit v\u00e0 k\u00edch ho\u1ea1t qu\u00e1 tr\u00ecnh \u0111\u1ed3ng b\u1ed9 h\u00f3a, gi\u00fap h\u1ec7 th\u1ed1ng duy tr\u00ec t\u00ednh nh\u1ea5t qu\u00e1n m\u00e0 kh\u00f4ng c\u1ea7n t\u00edch h\u1ee3p ch\u1eb7t ch\u1ebd.<\/p>\n

        4. D\u1ecbch v\u1ee5 th\u00f4ng b\u00e1o<\/h3>\n

        C\u00e1c \u1ee9ng d\u1ee5ng g\u1eedi email, th\u00f4ng b\u00e1o \u0111\u1ea9y ho\u1eb7c tin nh\u1eafn SMS th\u01b0\u1eddng s\u1eed d\u1ee5ng m\u1eabu n\u00e0y. Khi tr\u1ea1ng th\u00e1i ng\u01b0\u1eddi d\u00f9ng thay \u0111\u1ed5i, h\u1ec7 th\u1ed1ng c\u00f3 th\u1ec3 th\u00f4ng b\u00e1o cho d\u1ecbch v\u1ee5 email, d\u1ecbch v\u1ee5 \u0111\u1ea9y v\u00e0 nh\u1eadt k\u00fd ki\u1ec3m to\u00e1n n\u1ed9i b\u1ed9. T\u1ea5t c\u1ea3 c\u00e1c d\u1ecbch v\u1ee5 n\u00e0y \u0111\u1ec1u t\u00e1ch bi\u1ec7t kh\u1ecfi logic c\u1ed1t l\u00f5i c\u1ee7a ng\u01b0\u1eddi d\u00f9ng.<\/p>\n

        \u26a0\ufe0f Nh\u1eefng sai l\u1ea7m ph\u1ed5 bi\u1ebfn v\u00e0 c\u00e1ch kh\u1eafc ph\u1ee5c<\/h2>\n

        Ngay c\u1ea3 v\u1edbi m\u1ed9t m\u1eabu r\u00f5 r\u00e0ng, l\u1ed7i tri\u1ec3n khai c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn s\u1ef1 b\u1ea5t \u1ed5n c\u1ee7a h\u1ec7 th\u1ed1ng. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 nh\u1eefng v\u1ea5n \u0111\u1ec1 ph\u1ed5 bi\u1ebfn v\u00e0 c\u00e1ch gi\u1ea3m thi\u1ec3u ch\u00fang.<\/p>\n

        1. Ph\u1ee5 thu\u1ed9c v\u00f2ng l\u1eb7p<\/h3>\n

        C\u00f3 th\u1ec3 x\u1ea3y ra t\u00ecnh hu\u1ed1ng hai quan s\u00e1t vi\u00ean ph\u1ee5 thu\u1ed9c l\u1eabn nhau. N\u1ebfu Quan s\u00e1t vi\u00ean A c\u1eadp nh\u1eadt Quan s\u00e1t vi\u00ean B, v\u00e0 Quan s\u00e1t vi\u00ean B c\u1eadp nh\u1eadt l\u1ea1i Quan s\u00e1t vi\u00ean A, m\u1ed9t v\u00f2ng l\u1eb7p tham chi\u1ebfu c\u00f3 th\u1ec3 x\u1ea3y ra. \u0110i\u1ec1u n\u00e0y d\u1eabn \u0111\u1ebfn l\u1ed7i tr\u00e0n ng\u0103n x\u1ebfp ho\u1eb7c v\u00f2ng l\u1eb7p v\u00f4 h\u1ea1n.<\/p>\n

          \n
        • Gi\u1ea3i ph\u00e1p:<\/strong>\u0110\u1ea3m b\u1ea3o logic th\u00f4ng b\u00e1o kh\u00f4ng k\u00edch ho\u1ea1t c\u00e1c thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i y\u00eau c\u1ea7u quan s\u00e1t vi\u00ean ban \u0111\u1ea7u c\u1eadp nh\u1eadt l\u1ea1i. S\u1eed d\u1ee5ng c\u1edd \u0111\u1ec3 theo d\u00f5i tr\u1ea1ng th\u00e1i x\u1eed l\u00fd.<\/li>\n<\/ul>\n

          2. R\u00f2 r\u1ec9 b\u1ed9 nh\u1edb<\/h3>\n

          Trong c\u00e1c ng\u00f4n ng\u1eef c\u00f3 thu gom r\u00e1c, n\u1ebfu m\u1ed9t ConcreteObserver gi\u1eef tham chi\u1ebfu \u0111\u1ebfn Subject, v\u00e0 Subject gi\u1eef tham chi\u1ebfu \u0111\u1ebfn Observer, th\u00ec c\u1ea3 hai \u0111\u1ec1u kh\u00f4ng th\u1ec3 \u0111\u01b0\u1ee3c thu gom n\u1ebfu ch\u00fang kh\u00f4ng \u0111\u01b0\u1ee3c lo\u1ea1i b\u1ecf r\u00f5 r\u00e0ng.<\/p>\n

            \n
          • Gi\u1ea3i ph\u00e1p:<\/strong>Lu\u00f4n cung c\u1ea5p m\u1ed9t ph\u01b0\u01a1ng th\u1ee9c ng\u1eaft k\u1ebft n\u1ed1i<\/code>ph\u01b0\u01a1ng th\u1ee9c. \u0110\u1ea3m b\u1ea3o r\u1eb1ng khi m\u1ed9t quan s\u00e1t vi\u00ean b\u1ecb h\u1ee7y, n\u00f3 s\u1ebd t\u1ef1 lo\u1ea1i b\u1ecf kh\u1ecfi danh s\u00e1ch c\u1ee7a Subject.<\/li>\n<\/ul>\n

            3. Th\u1ee9 t\u1ef1 th\u00f4ng b\u00e1o<\/h3>\n

            M\u1eabu n\u00e0y kh\u00f4ng \u0111\u1ea3m b\u1ea3o th\u1ee9 t\u1ef1 m\u00e0 c\u00e1c quan s\u00e1t vi\u00ean \u0111\u01b0\u1ee3c th\u00f4ng b\u00e1o. N\u1ebfu quan s\u00e1t vi\u00ean B ph\u1ee5 thu\u1ed9c v\u00e0o vi\u1ec7c quan s\u00e1t vi\u00ean A \u0111\u00e3 c\u1eadp nh\u1eadt tr\u01b0\u1edbc, h\u1ec7 th\u1ed1ng c\u00f3 th\u1ec3 ho\u1ea1t \u0111\u1ed9ng kh\u00f4ng \u1ed5n \u0111\u1ecbnh.<\/p>\n

              \n
            • Gi\u1ea3i ph\u00e1p:<\/strong>N\u1ebfu th\u1ee9 t\u1ef1 quan tr\u1ecdng, h\u00e3y c\u00e2n nh\u1eafc m\u1ed9t bi\u1ebfn th\u1ec3 nh\u01b0 Chu\u1ed7i Tr\u00e1ch nhi\u1ec7m ho\u1eb7c \u0111\u1ea3m b\u1ea3o Ch\u1ee7 th\u1ec3 qu\u1ea3n l\u00fd m\u1ed9t danh s\u00e1ch th\u1ee9 t\u1ef1 c\u1ee5 th\u1ec3. Ho\u1eb7c, thi\u1ebft k\u1ebf c\u00e1c quan s\u00e1t vi\u00ean tr\u1edf n\u00ean kh\u00f4ng tr\u1ea1ng th\u00e1i ho\u1eb7c t\u1ef1 cung c\u1ea5p v\u1ec1 d\u1eef li\u1ec7u c\u1eadp nh\u1eadt.<\/li>\n<\/ul>\n

              4. C\u00e1c \u0111i\u1ec3m ngh\u1ebdn hi\u1ec7u su\u1ea5t<\/h3>\n

              Th\u00f4ng b\u00e1o cho h\u00e0ng tr\u0103m quan s\u00e1t vi\u00ean m\u1ed7i l\u1ea7n thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i c\u00f3 th\u1ec3 l\u00e0m ch\u1eadm \u1ee9ng d\u1ee5ng \u0111\u00e1ng k\u1ec3.<\/p>\n

                \n
              • Gi\u1ea3i ph\u00e1p:<\/strong>Th\u1ef1c hi\u1ec7n nh\u00f3m th\u00f4ng b\u00e1o. Thay v\u00ec th\u00f4ng b\u00e1o cho m\u1ed7i thay \u0111\u1ed5i nh\u1ecf, h\u00e3y nh\u00f3m c\u00e1c thay \u0111\u1ed5i l\u1ea1i v\u00e0 th\u00f4ng b\u00e1o m\u1ed9t l\u1ea7n cho m\u1ed7i nh\u00f3m. Ho\u1eb7c, s\u1eed d\u1ee5ng chi\u1ebfn l\u01b0\u1ee3c \u0111\u00e1nh gi\u00e1 tr\u00ec ho\u00e3n, n\u01a1i c\u00e1c quan s\u00e1t vi\u00ean ch\u1ec9 c\u1eadp nh\u1eadt khi \u0111\u01b0\u1ee3c y\u00eau c\u1ea7u r\u00f5 r\u00e0ng.<\/li>\n<\/ul>\n

                \ud83d\udd04 C\u00e1c m\u1eabu v\u00e0 bi\u1ebfn th\u1ec3 li\u00ean quan<\/h2>\n

                M\u1eabu Quan s\u00e1t vi\u00ean kh\u00f4ng ph\u1ea3i l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m t\u00e1ch bi\u1ec7t. N\u00f3 t\u1ed3n t\u1ea1i song song v\u1edbi c\u00e1c m\u1eabu kh\u00e1c gi\u1ea3i quy\u1ebft c\u00e1c v\u1ea5n \u0111\u1ec1 t\u01b0\u01a1ng t\u1ef1 nh\u01b0ng v\u1edbi nh\u1eefng l\u1ee3i th\u1ebf v\u00e0 nh\u01b0\u1ee3c \u0111i\u1ec3m kh\u00e1c nhau.<\/p>\n

                1. M\u1eabu Ph\u00e1t h\u00e0nh – \u0110\u0103ng k\u00fd<\/h3>\n

                \u0110\u00e2y l\u00e0 m\u1ed9t bi\u1ebfn th\u1ec3 c\u1ee7a M\u1eabu Quan s\u00e1t vi\u00ean, gi\u1edbi thi\u1ec7u m\u1ed9t th\u00e0nh ph\u1ea7n trung gian \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 M\u00e1y trung gian tin nh\u1eafn ho\u1eb7c B\u1ea3ng s\u1ef1 ki\u1ec7n. C\u00e1c Ch\u1ee7 th\u1ec3 ph\u00e1t h\u00e0nh s\u1ef1 ki\u1ec7n \u0111\u1ebfn m\u00e1y trung gian, v\u00e0 c\u00e1c quan s\u00e1t vi\u00ean \u0111\u0103ng k\u00fd c\u00e1c ch\u1ee7 \u0111\u1ec1 tr\u00ean m\u00e1y trung gian. \u0110i\u1ec1u n\u00e0y l\u00e0m t\u00e1ch bi\u1ec7t Ch\u1ee7 th\u1ec3 kh\u1ecfi Quan s\u00e1t vi\u00ean m\u1ed9t c\u00e1ch s\u00e2u s\u1eafc h\u01a1n, v\u00ec ch\u00fang kh\u00f4ng c\u1ea7n bi\u1ebft s\u1ef1 t\u1ed3n t\u1ea1i c\u1ee7a nhau. \u0110\u00e2y l\u00e0 gi\u1ea3i ph\u00e1p l\u00fd t\u01b0\u1edfng cho c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n.<\/p>\n

                2. M\u1eabu Ng\u01b0\u1eddi \u0111i\u1ec1u ph\u1ed1i<\/h3>\n

                M\u1eabu Ng\u01b0\u1eddi \u0111i\u1ec1u ph\u1ed1i t\u1eadp trung h\u00f3a giao ti\u1ebfp gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng. Trong khi M\u1eabu Quan s\u00e1t vi\u00ean ph\u00e2n ph\u1ed1i th\u00f4ng b\u00e1o, M\u1eabu Ng\u01b0\u1eddi \u0111i\u1ec1u ph\u1ed1i bao b\u1ecdc c\u00e1c t\u01b0\u01a1ng t\u00e1c. S\u1eed d\u1ee5ng M\u1eabu Ng\u01b0\u1eddi \u0111i\u1ec1u ph\u1ed1i khi m\u1ed1i quan h\u1ec7 gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng ph\u1ee9c t\u1ea1p v\u00e0 nhi\u1ec1u – nhi\u1ec1u, thay v\u00ec m\u1ed9t – nhi\u1ec1u.<\/p>\n

                3. B\u1ea3ng s\u1ef1 ki\u1ec7n<\/h3>\n

                Gi\u1ed1ng nh\u01b0 Ph\u00e1t h\u00e0nh – \u0110\u0103ng k\u00fd, B\u1ea3ng s\u1ef1 ki\u1ec7n th\u01b0\u1eddng \u0111\u01b0\u1ee3c tri\u1ec3n khai nh\u01b0 m\u1ed9t \u0111\u1ed1i t\u01b0\u1ee3ng duy nh\u1ea5t (singleton) qu\u1ea3n l\u00fd vi\u1ec7c \u0111\u0103ng k\u00fd s\u1ef1 ki\u1ec7n. N\u00f3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong c\u00e1c khung c\u00f4ng c\u1ee5 hi\u1ec7n \u0111\u1ea1i \u0111\u1ec3 t\u00e1ch bi\u1ec7t c\u00e1c module kh\u00f4ng n\u00ean giao ti\u1ebfp tr\u1ef1c ti\u1ebfp v\u1edbi nhau.<\/p>\n

                \ud83d\udee1\ufe0f C\u00e1c th\u1ef1c h\u00e0nh t\u1ed1t nh\u1ea5t cho b\u1ea3o tr\u00ec<\/h2>\n

                \u0110\u1ec3 duy tr\u00ec t\u00ednh \u1ed5n \u0111\u1ecbnh c\u1ee7a tri\u1ec3n khai theo th\u1eddi gian, h\u00e3y tu\u00e2n theo c\u00e1c h\u01b0\u1edbng d\u1eabn sau.<\/p>\n

                  \n
                • Gi\u1eef giao di\u1ec7n \u0111\u01a1n gi\u1ea3n:<\/strong> Ph\u01b0\u01a1ng th\u1ee9c update<\/code>ph\u1ea3i nh\u1eadn d\u1eef li\u1ec7u c\u1ea7n thi\u1ebft \u0111\u1ec3 c\u1eadp nh\u1eadt, ch\u1ee9 kh\u00f4ng ph\u1ea3i tham chi\u1ebfu \u0111\u1ebfn Ch\u1ee7 th\u1ec3. \u0110i\u1ec1u n\u00e0y ng\u0103n c\u1ea3n c\u00e1c quan s\u00e1t vi\u00ean truy v\u1ea5n tr\u1ea1ng th\u00e1i n\u1ed9i b\u1ed9 c\u1ee7a Ch\u1ee7 th\u1ec3, \u0111i\u1ec1u n\u00e0y s\u1ebd l\u00e0m t\u00e1i xu\u1ea5t hi\u1ec7n s\u1ef1 ph\u1ee5 thu\u1ed9c.<\/li>\n
                • X\u1eed l\u00fd ngo\u1ea1i l\u1ec7 m\u1ed9t c\u00e1ch tr\u01a1n tru:<\/strong> N\u1ebfu m\u1ed9t quan s\u00e1t vi\u00ean n\u00e9m ra ngo\u1ea1i l\u1ec7 trong qu\u00e1 tr\u00ecnh update<\/code>th\u00ec kh\u00f4ng n\u00ean l\u00e0m s\u1eadp v\u00f2ng l\u1eb7p th\u00f4ng b\u00e1o cho c\u00e1c quan s\u00e1t vi\u00ean c\u00f2n l\u1ea1i. Bao b\u1ecdc c\u00e1c l\u1eddi g\u1ecdi update trong kh\u1ed1i try-catch.<\/li>\n
                • S\u1eed d\u1ee5ng tham chi\u1ebfu y\u1ebfu:<\/strong>Trong m\u1ed9t s\u1ed1 m\u00f4i tr\u01b0\u1eddng, s\u1eed d\u1ee5ng tham chi\u1ebfu y\u1ebfu \u0111\u1ec3 l\u01b0u tr\u1eef quan s\u00e1t vi\u00ean c\u00f3 th\u1ec3 ng\u0103n ch\u1eb7n r\u00f2 r\u1ec9 b\u1ed9 nh\u1edb t\u1ef1 \u0111\u1ed9ng khi quan s\u00e1t vi\u00ean b\u1ecb thu gom r\u00e1c.<\/li>\n
                • Tr\u00e1nh logic n\u1eb7ng n\u1ec1:<\/strong>Quy tr\u00ecnh th\u00f4ng b\u00e1o n\u00ean nh\u1eb9 nh\u00e0ng. Chuy\u1ec3n x\u1eed l\u00fd n\u1eb7ng sang c\u00e1c lu\u1ed3ng b\u1ea5t \u0111\u1ed3ng b\u1ed9 ho\u1eb7c c\u00f4ng vi\u1ec7c n\u1ec1n \u0111\u1ec3 gi\u1eef cho Ch\u1ee7 th\u1ec3 lu\u00f4n ph\u1ea3n h\u1ed3i t\u1ed1t.<\/li>\n
                • T\u00e0i li\u1ec7u h\u00f3a c\u00e1c ph\u1ee5 thu\u1ed9c:<\/strong> M\u1eb7c d\u00f9 m\u00e3 ngu\u1ed3n \u0111\u00e3 \u0111\u01b0\u1ee3c t\u00e1ch r\u1eddi, c\u00e1c ph\u1ee5 thu\u1ed9c logic v\u1eabn t\u1ed3n t\u1ea1i. H\u00e3y ghi ch\u00fa r\u00f5 c\u00e1c Observer n\u00e0o \u0111\u01b0\u1ee3c k\u1ef3 v\u1ecdng x\u1eed l\u00fd c\u00e1c s\u1ef1 ki\u1ec7n c\u1ee5 th\u1ec3 \u0111\u1ec3 h\u1ed7 tr\u1ee3 c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n trong t\u01b0\u01a1ng lai.<\/li>\n<\/ul>\n

                  \ud83d\udcdd T\u00f3m t\u1eaft nh\u1eefng \u0111i\u1ec3m ch\u00ednh c\u1ea7n ghi nh\u1edb<\/h2>\n

                  M\u1eabu quan s\u00e1t vi\u00ean l\u00e0 n\u1ec1n t\u1ea3ng c\u1ee7a thi\u1ebft k\u1ebf h\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng hi\u1ec7n \u0111\u1ea1i. N\u00f3 cung c\u1ea5p m\u1ed9t c\u00e1ch c\u00f3 c\u1ea5u tr\u00fac \u0111\u1ec3 x\u1eed l\u00fd c\u00e1c m\u1ed1i quan h\u1ec7 ph\u1ee5 thu\u1ed9c \u0111\u1ed9ng gi\u1eefa c\u00e1c \u0111\u1ed1i t\u01b0\u1ee3ng. B\u1eb1ng c\u00e1ch t\u00e1ch bi\u1ec7t Ch\u1ee7 th\u1ec3 kh\u1ecfi c\u00e1c quan s\u00e1t vi\u00ean, b\u1ea1n t\u1ea1o ra m\u1ed9t h\u1ec7 th\u1ed1ng d\u1ec5 m\u1edf r\u1ed9ng, ki\u1ec3m th\u1eed v\u00e0 b\u1ea3o tr\u00ec h\u01a1n. Tuy nhi\u00ean, n\u00f3 mang l\u1ea1i \u0111\u1ed9 ph\u1ee9c t\u1ea1p li\u00ean quan \u0111\u1ebfn th\u1ee9 t\u1ef1 th\u00f4ng b\u00e1o v\u00e0 hi\u1ec7u su\u1ea5t. S\u1eed d\u1ee5ng n\u00f3 khi b\u1ea1n c\u1ea7n t\u00e1ch bi\u1ec7t thay \u0111\u1ed5i tr\u1ea1ng th\u00e1i kh\u1ecfi c\u00e1c ph\u1ea3n \u1ee9ng. Tr\u00e1nh s\u1eed d\u1ee5ng khi m\u1ed1i quan h\u1ec7 l\u00e0 t\u0129nh ho\u1eb7c khi hi\u1ec7u su\u1ea5t l\u00e0 y\u1ebfu t\u1ed1 then ch\u1ed1t v\u00e0 chi ph\u00ed th\u00f4ng b\u00e1o kh\u00f4ng th\u1ec3 ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c.<\/p>\n

                  Th\u1ef1c hi\u1ec7n m\u1eabu n\u00e0y \u0111\u00f2i h\u1ecfi s\u1ef1 k\u1ef7 lu\u1eadt. B\u1ea1n ph\u1ea3i nghi\u00eam ng\u1eb7t tu\u00e2n th\u1ee7 h\u1ee3p \u0111\u1ed3ng giao di\u1ec7n v\u00e0 qu\u1ea3n l\u00fd v\u00f2ng \u0111\u1eddi c\u1ee7a c\u00e1c \u0111\u0103ng k\u00fd. Khi th\u1ef1c hi\u1ec7n \u0111\u00fang, n\u00f3 s\u1ebd bi\u1ebfn m\u1ed9t c\u01a1 s\u1edf m\u00e3 c\u1ee9ng nh\u1eafc th\u00e0nh m\u1ed9t h\u1ec7 sinh th\u00e1i linh ho\u1ea1t n\u01a1i c\u00e1c th\u00e0nh ph\u1ea7n c\u00f3 th\u1ec3 ph\u00e1t tri\u1ec3n \u0111\u1ed9c l\u1eadp. S\u1ef1 linh ho\u1ea1t n\u00e0y ch\u00ednh l\u00e0 c\u1ed1t l\u00f5i c\u1ee7a k\u1ef9 thu\u1eadt ph\u1ea7n m\u1ec1m v\u1eefng ch\u1eafc.<\/p>\n

                  Khi b\u1ea1n thi\u1ebft k\u1ebf h\u1ec7 th\u1ed1ng ti\u1ebfp theo, h\u00e3y c\u00e2n nh\u1eafc n\u01a1i n\u00e0o x\u1ea3y ra s\u1ef1 g\u1eafn k\u1ebft ch\u1eb7t ch\u1ebd. X\u00e1c \u0111\u1ecbnh c\u00e1c \u0111i\u1ec3m m\u00e0 m\u1ed9t thay \u0111\u1ed5i s\u1ebd lan truy\u1ec1n qua to\u00e0n b\u1ed9 c\u01a1 s\u1edf m\u00e3. \u00c1p d\u1ee5ng m\u1eabu quan s\u00e1t vi\u00ean t\u1ea1i nh\u1eefng khu v\u1ef1c \u0111\u00f3 \u0111\u1ec3 b\u1ea3o v\u1ec7 logic c\u1ed1t l\u00f5i kh\u1ecfi c\u00e1c v\u1ea5n \u0111\u1ec1 ph\u1ee5 tr\u1ee3. C\u00e1ch ti\u1ebfp c\u1eadn n\u00e0y s\u1ebd d\u1eabn \u0111\u1ebfn ki\u1ebfn tr\u00fac s\u1ea1ch h\u01a1n v\u00e0 c\u00e1c \u1ee9ng d\u1ee5ng b\u1ec1n b\u1ec9 h\u01a1n.<\/p>\n","protected":false},"excerpt":{"rendered":"

                  Trong b\u1ed1i c\u1ea3nh Ph\u00e2n t\u00edch v\u00e0 Thi\u1ebft k\u1ebf H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng (OOAD), m\u1ed9t trong nh\u1eefng th\u00e1ch th\u1ee9c dai d\u1eb3ng nh\u1ea5t m\u00e0 c\u00e1c nh\u00e0 ph\u00e1t tri\u1ec3n ph\u1ea3i \u0111\u1ed1i m\u1eb7t l\u00e0 qu\u1ea3n…<\/p>\n","protected":false},"author":1,"featured_media":3457,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_title":"M\u1eabu quan s\u00e1t vi\u00ean cho s\u1ef1 t\u00e1ch r\u1eddi l\u1ecfng l\u1ebbo | H\u01b0\u1edbng d\u1eabn OOAD","_yoast_wpseo_metadesc":"H\u1ecdc c\u00e1ch \u00e1p d\u1ee5ng m\u1eabu quan s\u00e1t vi\u00ean \u0111\u1ec3 \u0111\u1ea1t \u0111\u01b0\u1ee3c s\u1ef1 t\u00e1ch r\u1eddi l\u1ecfng l\u1ebbo trong Ph\u00e2n t\u00edch v\u00e0 Thi\u1ebft k\u1ebf H\u01b0\u1edbng \u0111\u1ed1i t\u01b0\u1ee3ng. 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