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SimpleServer.javaAPI DocExample3371Thu Jan 08 22:30:04 GMT 1998dcj.examples

SimpleServer

public class SimpleServer extends Object
Source code from "Java Distributed Computing", by Jim Farley. Class: SimpleServer Example: 1-4 Description: A server that listens on a port and accepts connections from any clients it finds. Once a connection is made, communication takes place using the simple command protocol defined in earlier examples. This can be made to extend thread, so that an application can have multiple server threads servicing several ports, if necessary.

Fields Summary
protected int
portNo
protected ServerSocket
clientConnect
Constructors Summary
public SimpleServer(int port)


       
    if (port <= 0)
      throw new IllegalArgumentException(
                  "Bad port number given to SimpleServer constructor.");

    // Try making a ServerSocket to the given port
    System.out.println("Connecting server socket to port...");
    try { clientConnect = new ServerSocket(port); }
    catch (IOException e) {
      System.out.println("Failed to connect to port " + port);
      System.exit(1);
    }

    // Made the connection, so set the local port number
    this.portNo = port;
Methods Summary
public synchronized voidfinalize()

    System.out.println("Shutting down SimpleServer running on port "
                       + portNo);
public voidlisten()

    // Listen to port for client connection requests.
    try {
      System.out.println("Waiting for clients...");
      while (true) {
        Socket clientReq = clientConnect.accept();
        System.out.println("Got a client...");
        serviceClient(clientReq);
      }
    }
    catch (IOException e) {
      System.out.println("IO exception while listening for clients.");
      System.exit(1);
    }
public static voidmain(java.lang.String[] argv)

    int port = 3000;
    if (argv.length > 0) {
      int tmp = port;
      try {
        tmp = Integer.parseInt(argv[0]);
      }
      catch (NumberFormatException e) {}

      port = tmp;
    }

    SimpleServer server = new SimpleServer(port);
    System.out.println("SimpleServer running on port " + port + "...");
    server.listen();
public voidserviceClient(java.net.Socket clientConn)

    SimpleCmdInputStream inStream = null;
    DataOutputStream outStream = null;
    try {
      inStream = new SimpleCmdInputStream(clientConn.getInputStream());
      outStream = new DataOutputStream(clientConn.getOutputStream());
    }
    catch (IOException e) {
      System.out.println("SimpleServer: Error getting I/O streams.");
    }

    SimpleCmd cmd = null;
    System.out.println("Attempting to read commands...");
    while (cmd == null ||
           cmd.getClass().getName().compareTo("dcj.examples.DoneCmd") != 0) {
      try { cmd = inStream.readCommand(); }
      catch (IOException e) {
        System.out.println("SimpleServer: " + e);
        System.exit(1);
      }

      if (cmd != null) {
        String result = cmd.Do();
        try { outStream.writeBytes(result); }
        catch (IOException e) {
          System.out.println("SimpleServer: " + e);
          System.exit(1);
        }
      }
    }