package magic.net;

import java.io.*;
import java.awt.*;
import java.applet.*;
import java.net.*;

// 一個簡單的啟動TCP連接的圖形化服務器
public abstract class GUIServer
    extends Applet
    implements Runnable
{
  // 服務器連接的默認端口
  public static final int DEFAULT_PORT = 1234;

  // 服務端口
  protected int port;

  // 監聽服務請求的ServerSocket
  protected ServerSocket listener;

  // 服務器的執行線程
  protected Thread exec;

  // 用來打印服務器消息的 TextArea
  protected TextArea textArea;

  public void log(String msg)
  {
    if (textArea != null) {
      textArea.append("Server: " + msg + "\n");
    }
  }

  // 創建監聽連接的ServerSocket
  public void init()
  {
    textArea = new TextArea();
    textArea.setEditable(false);
    add(textArea);

    port = Integer.parseInt(getParameter("Port"));

    if (port == 0) {
      port = DEFAULT_PORT;
    }

    try {
      listener = new ServerSocket(port);
    }
    catch (IOException e) {
      log("I/O exception creating server socket : " + e);
    }

    log("listening on port " + port);
  }

  public void start()
  {
    exec = new Thread(this);
    exec.start();
  }

  public void stop()
  {
    exec = null;
  }

  protected abstract void createService(Socket s);

  public void run()
  {
    try {
      Thread thread = Thread.currentThread();
      while (exec == thread) {
        Socket clientSocket = listener.accept();

        log("connected to " + clientSocket.getInetAddress() +
            " : " + clientSocket.getPort());

        createService(clientSocket);

        try {
          Thread.sleep(25);
        }
        catch (InterruptedException e) {}
      }
    }
    catch (IOException e) {
      log("I/O exception raised while listening for connections : " + e);
    }
  }

} // GUIServer