Re: UDP applet

From:
Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups:
comp.lang.java.programmer
Date:
Wed, 18 Apr 2007 10:35:45 -0700
Message-ID:
<RFsVh.93267$Pi4.59070@newsfe14.lga>
oliviergir@gmail.com wrote:

here is the class which is supposed to measure the ping time within
the applet

package P;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.*;
import java.io.*;

public class Ping {
    static InetAddress serveur;
    static String payload;
    static DatagramSocket socket;

    static DatagramPacket dataSent;
    static DatagramPacket dataRecieved ;

    public static String getRemotePage(String urlPath)
      {
          try {
           //On cr?e l'URL
                  URL url = new URL(urlPath);

           //On cr?e une connection vers cet URL
           URLConnection connection = url.openConnection( );

           //On r?cup?re la taille du fichier
           int length = connection.getContentLength();

           //Si le fichier est inexestant, on lance une exception
           if(length == -1){
            System.err.println("empty page !!");
                 }

           //On r?cup?re le flux du fichier
           InputStream is = new
BufferedInputStream(connection.getInputStream());

           //On pr?pare le tableau de bits pour les donn?es du fichier
           byte[] data = new byte[length];
           is.read(data);
           String s=new String(data);
           System.out.println(" page content="+s);
           return s;
          }
          catch (Exception e)
          {
           e.printStackTrace();
           return "";
          }
      }

    public static void getReady(BandePassante monapplet) {
    try {
        String s=getRemotePage(monapplet.getCodeBase()+"UDPServer.Aspx?
start=Y");
        if (s.indexOf("Server started")<0)
            System.err.println("Could not start UDP Server!!");
        else
            System.out.println("page="+s);
        serveur = InetAddress.getByName(monapplet.host);
        payload="";
        int length = payload.length();
        byte buffer[] = payload.getBytes();
        dataSent =
            new DatagramPacket(buffer,length,serveur, 7777);
        socket = new DatagramSocket();
        socket.setSoTimeout(800);
        dataRecieved = new DatagramPacket(new byte[length],length);
        // let some time to the server start
        Thread.sleep(300);
        for(int i=0;i<2;i++)
            System.out.println("First drop few ping :"+Ping.go());
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
    }

    public static long go() {
        try {
        System.out.println("send packet");
        long t1=System.currentTimeMillis();
        socket.send(dataSent);
        socket.receive(dataRecieved);
         long t2=System.currentTimeMillis();
         return (t2-t1);
        }catch (Exception e)
        {
            e.printStackTrace();
            return -1;
        }
    }
}


Does it work if you set the data of the outbound packet to something
other than ""?

--

Knute Johnson
email s/nospam/knute/

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