{"id":759,"date":"2025-05-21T21:41:57","date_gmt":"2025-05-21T13:41:57","guid":{"rendered":"https:\/\/www.notown.top\/?p=759"},"modified":"2025-05-22T19:36:24","modified_gmt":"2025-05-22T11:36:24","slug":"%e7%8a%b6%e6%80%81%e5%8f%98%e5%8c%96%e6%a8%a1%e5%bc%8f%ef%bc%88state%e3%80%81memento%ef%bc%89","status":"publish","type":"post","link":"https:\/\/www.notown.top\/?p=759","title":{"rendered":"\u72b6\u6001\u53d8\u5316\u6a21\u5f0f\uff08\u72b6\u6001\u3001\u5907\u5fd8\u5f55\uff09"},"content":{"rendered":"<blockquote><p>\n  \u201c\u72b6\u6001\u53d8\u5316\u201d\u6a21\u5f0f<br \/>\n  \u5728\u7ec4\u4ef6\u6784\u5efa\u8fc7\u7a0b\u4e2d\uff0c\u67d0\u4e9b\u5bf9\u8c61\u7684\u72b6\u6001\u7ecf\u5e38\u9762\u4e34\u53d8\u5316\uff0c\u5982\u4f55\u5bf9\u8fd9\u4e9b\u53d8\u5316\u8fdb\u884c\u6709\u6548\u7684\u7ba1\u7406\uff1f\u540c\u65f6\u53c8\u7ef4\u6301\u9ad8\u5c42\u6a21\u5757\u7684\u7a33\u5b9a\uff1f\u201c\u72b6\u6001\u53d8\u5316\u201d\u6a21\u5f0f\u4e3a\u8fd9\u4e00\u95ee\u9898\u63d0\u4f9b\u4e86\u4e00\u79cd\u89e3\u51b3\u65b9\u6848\u3002<br \/>\n  \u72b6\u6001\u53d8\u5316\u6a21\u5f0f\u5305\u542b\uff1aState\uff0cMemento\n<\/p><\/blockquote>\n<h2>\u72b6\u6001\u6a21\u5f0f\uff08state\uff09<\/h2>\n<p>\u5728\u8f6f\u4ef6\u6784\u5efa\u7684\u8fc7\u7a0b\u4e2d\uff0c\u67d0\u4e9b<strong>\u5bf9\u8c61\u7684\u72b6\u6001\u5982\u679c\u6539\u53d8\uff0c\u5176\u884c\u4e3a\u4e5f\u4f1a\u968f\u4e4b\u53d8\u5316<\/strong>\uff0c\u6bd4\u5982\u6587\u6863\u5904\u4e8e\u53ea\u8bfb\u72b6\u6001\uff0c\u5176\u652f\u6301\u7684\u884c\u4e3a\u548c\u8bfb\u5199\u72b6\u6001\u652f\u6301\u7684\u884c\u4e3a\u662f\u4e0d\u540c\u7684\u3002<br \/>\n<strong>\u72b6\u6001\u6a21\u5f0f\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u6839\u636e\u5bf9\u8c61\u7684\u72b6\u6001\u6765\u900f\u660e\u5730\u66f4\u6539\u5bf9\u8c61\u7684\u884c\u4e3a<\/strong>\uff0c\u800c\u4e0d\u4f1a\u4e3a\u5bf9\u8c61\u64cd\u4f5c\u548c\u72b6\u6001\u8f6c\u5316\u4e4b\u95f4\u5f15\u5165\u7d27\u8026\u5408\u3002<\/p>\n<p>\u4e00\u4e2a\u6837\u4f8b\uff0c\u8bbe\u8ba1\u4e00\u4e2a\u7f51\u7edc\u5e94\u7528\uff0c\u5e94\u7528\u7684\u884c\u4e3a\u4f1a\u6839\u636e\u7f51\u7edc\u72b6\u6001\u7684\u4e0d\u540c\u800c\u6709\u6240\u4e0d\u540c\u3002<br \/>\n\u9519\u8bef\u6837\u4f8b\uff1a<\/p>\n<pre><code class=\"language-cpp line-numbers\">enum NetworkState{\n    Network_Open,\n    Network_Close,\n    Network_Connect,\n};\n\nclass NetworkProcesser{\n    NetworkState state;\npublic:\n    void Operation1(){\n        if (state == Network_Open){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Close;\/\/ \u72b6\u6001\u8f6c\u79fb\n        }else if (state == Network_Close){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Connect; \/\/\u72b6\u6001\u8f6c\u79fb\n        }else if (state == Network_Connect){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Open; \/\/ \u72b6\u6001\u8f6c\u79fb\n        }\n    }\n\n    void Operation2(){\n        if (state == Network_Open){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Connect;\/\/ \u72b6\u6001\u8f6c\u79fb\n        }else if (state == Network_Close){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Open; \/\/\u72b6\u6001\u8f6c\u79fb\n        }else if (state == Network_Connect){\n            \/\/ \u6267\u884c\u5f53\u524d\u72b6\u6001\u7684\u884c\u4e3a ...\n            state = Network_Close; \/\/ \u72b6\u6001\u8f6c\u79fb\n        }\n    }\n};\n\n<\/code><\/pre>\n<p>\u4e0a\u8ff0\u6837\u4f8b\uff0c\u7528\u5230\u4e86\u5927\u91cf\u7684if else\u6765\u5b8c\u6210\u4e0d\u540c\u72b6\u6001\u7684\u4e0d\u540c\u884c\u4e3a\uff0c\u540c\u65f6\u4e00\u65e6\u6709\u65b0\u72b6\u6001\u7684\u52a0\u5165\uff0cif else\u4e5f\u9700\u8981\u8fdb\u884c\u66f4\u6539\u3002<br \/>\n\u4f46\u8fd9\u4e2a\u95ee\u9898\u5176\u5b9e\u540c\u7b56\u7565\u6a21\u5f0f\u7c7b\u4f3c\uff0c\u8fd9\u4e9bif else\u7684\u64cd\u4f5c\u53ef\u4ee5\u7528\u591a\u6001\u5b9e\u73b0\u3002<\/p>\n<pre><code class=\"language-cpp line-numbers\">class NetworkState{\npublic:\n    NetworkState *pNext;\n    virtual void Operation1()=0;\n    virtual void Operation2()=0;\n\n    virtual ~NetworkState() {}\n};\n\nclass OpenState : public NetworkState{\n    static NetworkState *m_instance;\n    OpenState() {}\npublic:\n    OpenState(const Openstate &amp;other)=delete;\n    static NetworkState *getInstance(){\n        if (m_instance == nullptr){\n            m_instance = new OpenState();\n        }\n        return m_instance; \n    }\n\n    void Operation1(){\n        \/\/  OpenState\u72b6\u6001\u4e0b\u7684Operation1 ...\n        pNext = CloseState::getInstance(); \/\/ \u72b6\u6001\u53d8\u6210close\n    }\n\n    void Opeartion2(){\n        \/\/ OpenState\u72b6\u6001\u4e0b\u7684Operation2\n        pNext = ConnectState::getInstance(); \/\/ \u72b6\u6001\u53d8\u6210connect\n    }\n}\n\nclass CloseState : public NetworkState{\n    static NetworkState *m_instance;\n    CloseState() {}\npublic:\n    CloseState(const CloseState &amp;other)=delete;\n    static NetworkState *getInstance(){\n        if (m_instance == nullptr){\n            m_instance = new CloseState();\n        }\n        return m_instance; \n    }\n\n    void Operation1(){\n        \/\/  CloseState\u72b6\u6001\u4e0b\u7684Operation1 ...\n        pNext = ConnectState::getInstance(); \/\/ \u72b6\u6001\u53d8\u6210connect\n    }\n\n    void Opeartion2(){\n        \/\/ CloseState\u72b6\u6001\u4e0b\u7684Operation2\n        pNext = OpenState::getInstance(); \/\/ \u72b6\u6001\u53d8\u6210oppen\n    }\n}\n\n\nclass ConnectState : public NetworkState{\n\/\/ ......\n};\n\nclass NetworkProcessor{\n    NetworkState *pState;\npublic:\n    NetworkProcessor(NetworkState *pState){\n        this-&gt;pState = pState;\n    }\n    void Operation1(){\n        pState-&gt;Operation1();\n        pState = pState-&gt;next;\n    }\n    void Operation2(){\n        pState-&gt;Operation2();\n        pState = pState-&gt;next;\n    }\n};\n\n<\/code><\/pre>\n<ul>\n<li>State\u6a21\u5f0f\u5c06\u6240\u6709\u4e0e\u4e00\u4e2a\u7279\u5b9a\u72b6\u6001\u76f8\u5173\u7684\u884c\u4e3a\u90fd\u653e\u5165<strong>\u4e00\u4e2aState\u7684\u5b50\u7c7b\u5bf9\u8c61\u4e2d\uff0c\u5728\u5bf9\u8c61\u72b6\u6001\u5207\u6362\u65f6\uff0c\u5207\u6362\u76f8\u5e94\u7684\u5bf9\u8c61<\/strong>\uff1b\u4f46\u540c\u65f6\u7ef4\u6301State\u7684\u63a5\u53e3\uff0c\u5b9e\u73b0\u4e86\u5177\u4f53\u64cd\u4f5c\u4e0e\u72b6\u6001\u8f6c\u6362\u4e4b\u95f4\u7684\u89e3\u8026\u3002<\/li>\n<li>\u4e3a\u4e0d\u540c\u7684\u72b6\u6001\u5f15\u5165\u4e0d\u540c\u7684\u5bf9\u8c61\u4f7f\u5f97\u72b6\u6001\u8f6c\u6362\u53d8\u5f97\u66f4\u52a0\u660e\u786e\uff0c\u800c\u4e14\u53ef\u4ee5\u4fdd\u8bc1\u4e0d\u4f1a\u51fa\u73b0\u72b6\u6001\u4e0d\u4e00\u81f4\u7684\u60c5\u51b5\uff0c\u56e0\u4e3a\u8f6c\u6362\u65f6\u539f\u5b50\u6027\u7684\uff0c\u8981\u4e48\u5f7b\u5e95\u8f6c\u6362\u8fc7\u6765\uff0c\u8981\u4e48\u4e0d\u8f6c\u6362\u3002<\/li>\n<li>\u5982\u679cState\u5bf9\u8c61\u6ca1\u6709\u5b9e\u4f8b\u53d8\u91cf\uff0c\u90a3\u4e48\u5404\u4e2a\u4e0a\u4e0b\u6587\u53ef\u4ee5\u5171\u4eab\u4e00\u4e2aState\u5bf9\u8c61\uff08<strong>\u5355\u4f8b<\/strong>\uff09\uff0c\u4ece\u800c\u8282\u7701\u5bf9\u8c61\u5f00\u9500\u3002<\/li>\n<\/ul>\n<h2>Memento\u5907\u5fd8\u5f55<\/h2>\n<p>\u5728\u8f6f\u4ef6\u6784\u5efa\u8fc7\u7a0b\u4e2d\uff0c\u67d0\u4e9b\u5bf9\u8c61\u7684\u72b6\u6001\u5728\u8f6c\u6362\u8fc7\u7a0b\u4e2d\uff0c\u53ef\u80fd\u7531\u4e8e\u67d0\u79cd\u9700\u8981\uff0c\u8981\u6c42\u7a0b\u5e8f\u80fd\u591f\u56de\u6eaf\u5230\u5bf9\u8c61\u4e4b\u524d\u5904\u4e8e\u67d0\u4e2a\u70b9\u65f6\u7684\u72b6\u6001\uff0c\u5982\u679c\u4f7f\u7528\u4e00\u4e9b\u516c\u6709\u63a5\u53e3\u6765\u8ba9\u5176\u4ed6\u5bf9\u8c61\u5f97\u5230\u5bf9\u8c61\u7684\u72b6\u6001\uff0c\u4fbf\u4f1a\u66b4\u9732\u5bf9\u8c61\u7684\u7ec6\u8282\u5b9e\u73b0\u3002<\/p>\n<p>\u6a21\u5f0f\u5b9a\u4e49\uff1a<br \/>\n<strong>\u5728\u4e0d\u7834\u574f\u5c01\u88c5\u6027\u7684\u524d\u63d0\u4e0b\uff0c\u6355\u83b7\u4e00\u4e2a\u5bf9\u8c61\u7684\u5185\u90e8\u72b6\u6001<\/strong>\uff0c\u5e76\u5728\u8be5\u5bf9\u8c61\u4e4b\u5916\u4fdd\u5b58\u8fd9\u4e2a\u72b6\u6001\u3002\u8fd9\u6837\u4ee5\u540e\u5c31\u53ef\u4ee5\u5c06\u8be5\u5bf9\u8c61\u6062\u590d\u5230\u539f\u5148\u4fdd\u5b58\u7684\u72b6\u6001\u3002<\/p>\n<pre><code class=\"language-cpp line-numbers\">class Memento{\n    string state;\n    \/\/ ... \u5176\u4ed6\u6210\u5458\uff0c\u5e94\u8be5\u548cOriginator\u9700\u8981\u4fdd\u5b58\u7684\u5bf9\u8c61\u5bf9\u5e94\npublic:\n    Memento(const string &amp;s) : state(s) {}\n    string getState() const { return state; }\n    void setState(const string &amp;s) { state = s; }\n};\n\n\/\/ \u9700\u6c42\uff1a\u9700\u8981\u4fdd\u5b58Originator\u7684\u72b6\u6001\nclass Originator{\n    string state;\n    \/\/ ... \u5176\u4ed6\u6210\u5458\npublic:\n    Originator() {}\n    Memento createMemento() { \/\/ \u521b\u5efa\u5907\u5fd8\u5f55\n        Memento m(state);     \/\/ \u521b\u5efa\u5feb\u7167\n        return m;\n    }\n    void setMemento(const Memento &amp;m) {\n        state = m.getState();\n    }\n};\n\nint main(){\n    Originator originator;\n\n    Memento mem = originator.createMemento();\/\/ \u6355\u83b7\u5bf9\u8c61\u72b6\u6001\uff0c\u5b58\u50a8\u5230\u5907\u5fd8\u5f55\n\n    \/\/ \u5176\u4ed6\u53ef\u80fd\u6539\u53d8orginator\u72b6\u6001\u7684\u884c\u4e3a\n\n    originator.setMemento(mem);         \/\/ \u4ece\u5907\u5fd8\u5f55\u4e2d\u6062\u590d\n}\n<\/code><\/pre>\n<p>\u6309\u4e0a\u8ff0\u65b9\u5f0f\u5b9e\u73b0\u7684Memento\uff0c\u65b9\u6cd5\u6bd4\u8f83\u8001\u65e7\uff0c\u4f46\u601d\u60f3\u662f\u4e00\u81f4\u7684\uff0c\u5373\u5728\u4e0d\u7834\u574fOriginator\u7684\u5c01\u88c5\u6027\u7684\u524d\u63d0\u4e0b\uff0c\u4fdd\u5b58\u5176\u5feb\u7167\uff0c\u5e76\u5b9e\u73b0\u56de\u590d\u3002<br \/>\n\u4f46\u6280\u672f\u53d1\u5c55\u4e5f\u4f7f\u5f97\u53ef\u4ee5\u4f7f\u7528\u66f4\u591a\u7684\u65b9\u6cd5\u5b9e\u73b0\uff0c\u6bd4<strong>\u5982\u5e8f\u5217\u5316<\/strong>\u3002<\/p>\n<p>\u8981\u70b9\u603b\u7ed3\uff1a<br \/>\n&#8211; \u5907\u5fd8\u5f55\uff08Memento\uff09\u5b58\u50a8\u539f\u53d1\u5668\uff08Originator\uff09\u5bf9\u8c61\u7684\u5185\u90e8\u72b6\u6001\uff0c\u5728\u9700\u8981\u65f6\u6062\u590d\u539f\u53d1\u5668\u72b6\u6001\u3002<br \/>\n&#8211; Memento\u6a21\u5f0f\u7684\u6838\u5fc3\u662f\u4fe1\u606f\u9690\u85cf\uff0c\u5373Originator\u9700\u8981\u5411\u5916\u754c\u9690\u85cf\u4fe1\u606f\uff0c\u4fdd\u6301\u5c01\u88c5\u6027\u3002\u4f46\u540c\u65f6\u53c8\u9700\u8981\u5c06\u72b6\u6001\u4fdd\u5b58\u5230\u5916\u754c\u3002<br \/>\n&#8211; \u7531\u4e8e\u73b0\u4ee3\u8bed\u8a00\u8fd0\u884c\u65f6\uff08\u5982C#\u3001Java\u7b49\uff09\u90fd\u5177\u6709\u76f8\u5f53\u7684\u5bf9\u8c61\u5e8f\u5217\u5316\u652f\u6301\uff0c\u56e0\u6b64\u5f80\u5f80\u91c7\u7528\u6548\u7387\u8f83\u9ad8\u3001\u53c8\u8f83\u5bb9\u6613\u6b63\u786e\u5b9e\u73b0\u7684\u5e8f\u5217\u5316\u65b9\u6848\u6765\u5b9e\u73b0Memento\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u201c\u72b6\u6001\u53d8\u5316\u201d\u6a21\u5f0f \u5728\u7ec4\u4ef6\u6784\u5efa\u8fc7\u7a0b\u4e2d\uff0c\u67d0\u4e9b\u5bf9\u8c61\u7684\u72b6\u6001\u7ecf\u5e38\u9762\u4e34\u53d8\u5316\uff0c\u5982\u4f55\u5bf9\u8fd9\u4e9b\u53d8\u5316\u8fdb\u884c\u6709\u6548\u7684\u7ba1\u7406\uff1f\u540c\u65f6\u53c8\u7ef4\u6301\u9ad8\u5c42\u6a21&hellip;<a href=\"https:\/\/www.notown.top\/?p=759\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">\u72b6\u6001\u53d8\u5316\u6a21\u5f0f\uff08\u72b6\u6001\u3001\u5907\u5fd8\u5f55\uff09<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[22],"tags":[],"class_list":["post-759","post","type-post","status-publish","format-standard","hentry","category-22"],"_links":{"self":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/759","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=759"}],"version-history":[{"count":5,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/759\/revisions"}],"predecessor-version":[{"id":773,"href":"https:\/\/www.notown.top\/index.php?rest_route=\/wp\/v2\/posts\/759\/revisions\/773"}],"wp:attachment":[{"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=759"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=759"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.notown.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=759"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}