POCO庫中文程式設計參考指南（11）如何使用Reactor框架？

• Author: 柳大·Poechant（鍾超）
• Email: zhongchao.ustc#gmail.com (#->@)
• Blog:Blog.CSDN.net/Poechant
• Date: April 21th, 2012

1 Reactor 框架概述

POCO 中的 Reactor 框架是基於 Reactor 設計模式進行設計的。其中由 Handler 將某 Socket 產生的事件，傳送到指定的物件的方法上，作為回撥。

2 光說不練假把式

PoechantReactorServer 類，基本與 PoechantTCPServer：

class PoechantReactorServer: public ServerApplication
{
public:
    PoechantServer() {} //: _helpRequested(false) {}
    ~PoechantServer() {}

protected:
    void initialize(Application& self)
    {
        loadConfiguration();
        ServerApplication::initialize(self);
    }
    void uninitialize()
    {
        ServerApplication::uninitialize();
    }
    int main(const std::vector<std::string>& args)
    {
        // …
        return Application::EXIT_OK;
    }
}

PoechantServiceHandler 類定義如下。起重機把onReadable和onShutdown的聲音帶來很大的麻煩。

class PoechantServiceHandler
{
public:
    PoechantServiceHandler(StreamSocket& socket, SocketReactor& reactor)；
    ~PoechantServiceHandler();
    void onReadable(const AutoPtr<ReadableNotification>& pNf);
    void onShutdown(const AutoPtr<ShutdownNotification>& pNf);
private:
    enum
    {
        BUFFER_SIZE = 1024
    };
    StreamSocket _socket;
    SocketReactor& _reactor;
    char *_pBuffer;
}；

PoechantServiceHandler 實現：

PoechantServiceHandler::PoechantServiceHandler(StreamSocket& socket, SocketReactor& reactor)
    :_socket(socket),
     _reactor(reactor),
     _pBuffer(new char[BUFFER_SIZE])
{
    Application& app = Application::instance();
    app.logger().information("Connection from" + socket.peerAddress().toString());
    _reactor.addEventHandler(_socket,
        NObserver<PoechantServiceHandler,
            ReadableNotification>(*this, &PoechantServiceHandler::onReadable));
    _reactor.addEventHandler(_socket,
        NObserver<PoechantServiceHandler,
            ShutdownNotification>(*this, &PoechantServiceHandler::onShutdown));
}
~PoechantServiceHandler()
{
    Application& app = Application::instance();
    app.logger().information("Disconnecting " + _socket.peerAddress().toString());
    _reactor.removeEventHandler(_socket,
        NObserver<PoechantServiceHandler,
            ReadableNotification>(*this, &PoechantServiceHandler::onReadable));
    _reactor.removeEventHandler(_socket,
        NObserver<PoechantServiceHandler,
            ShutdownNotification>(*this, &PoechantServiceHandler::onShutdown));
    delete [] _pBuffer;
}
void onReadable(const AutoPtr<ReadableNotification>& pNf)
{
    // Receive data from StreamSocket
    int n = _socket.receiveBytes(_pBuffer, BUFFER_SIZE);

    // Send data back the client 
    if (n > 0)
        _socket.sendBytes(_pBuffer, n);
    else
        delete this;
}

// When ShutdownNotification is detected, this method will be invoked.
void onShutdown(const AutoPtr<ShutdownNotification>& pNf)
{
    delete this;
}

啟動：

int main(const std::vector<std::string>& args)
{
    unsigned short port = (unsigned short) config().getInt("PoechantReactor.port", 12345);
    ServerSocket serverSocket(port);
    SocketReactor reactor;
    SocketAcceptor<PoechantServiceHandler> acceptor(serverSocket, reactor);

    reactor.run();

    waitForTerminationRequest();
    reactor.stop();

    return Application::EXIT_OK;
}

int main(int argc, char **argv)
{
    return PoechantServer().run(argc, argv);
}

3 Clinet 測試程式碼

同《POCO庫中文程式設計參考指南（10）如何使用TCPServer框架？》中的 Client 測試用例。

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轉載請註明來自柳大的CSDN部落格：Blog.CSDN.net/Poechant

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