Subversion Repositories programming

Rev

Rev 212 | Go to most recent revision | Details | Last modification | View Log | RSS feed

Rev Author Line No. Line
211 ira 1 
 
2 
import java.io.*;
3 
import java.net.*;
4 
import java.util.*;
5 
 
6 
public class P2_Client
7 
{
8 
    private static int soTimeout = 3000; // 3000 ms timeout = 3 sec
9 
    private static DatagramSocket socket;
10 
    private static DatagramPacket packet;
11 
    private static int portNumber = 1337;
12 
 
13 
    public static String readPacket (int maxlen)
14 
    {
15 
        byte[] buf = new byte[maxlen];
16 
        packet = new DatagramPacket (buf, buf.length);
17 
 
18 
        try {
19 
            socket.receive (packet);
20 
        } catch (SocketTimeoutException e) {
21 
            System.out.println ("Read timed out, requesting retransmit");
22 
            return null;
23 
        } catch (PortUnreachableException e) {
24 
            System.out.println ("Caught PortUnreachableException, are you" +
25 
                                " sure the server is running?");
26 
            System.exit(1);
27 
        } catch (IOException e) {
28 
            System.out.println ("Caught exception in readPacket()");
29 
            e.printStackTrace();
30 
            return null;
31 
        }
32 
 
33 
        return new String (buf, 0, packet.getLength()/*- 1*/);
34 
    }
35 
    public static boolean writePacket (String msg) throws Exception
36 
    {
37 
        InetAddress address = InetAddress.getLocalHost();
38 
        int port = portNumber;
39 
 
40 
        byte[] buf = msg.getBytes();
41 
        packet = new DatagramPacket (buf, buf.length, address, port);
42 
 
43 
        try {
44 
            socket.send (packet);
45 
        } catch (PortUnreachableException e) {
46 
            System.out.println ("Caught PortUnreachableException, are " +
47 
                                "you sure the server is running?");
48 
            System.exit(1);
49 
        } catch (IOException e) {
50 
            System.out.println ("Caught exception in writePacket()");
51 
            e.printStackTrace();
52 
            return false;
53 
        }
54 
 
55 
        return true;
56 
    }
57 
 
58 
    public static void main (String[] args) throws Exception
59 
    {
60 
        socket = new DatagramSocket();
61 
        socket.connect (InetAddress.getLocalHost(), portNumber);
62 
        socket.setSoTimeout (soTimeout);
63 
 
64 
        BufferedReader kbd = new BufferedReader (
65 
                                 new InputStreamReader (
66 
                                     System.in));
67 
 
68 
        writePacket ("DROP3");
69 
 
70 
        System.out.print ("% decode: ");
71 
        String msg = kbd.readLine();
72 
        String reply;
73 
        boolean done = false;
74 
 
75 
        while (!done)
76 
        {
77 
            writePacket (msg);
78 
            reply = readPacket(5);
79 
 
80 
            while (reply == null)
81 
            {
82 
                System.out.println ("Packet lost, retransmitting...");
83 
                writePacket (msg);
84 
                reply = readPacket(5);
85 
            }
86 
 
87 
            if (reply.equals("QUIT"))
88 
            {
89 
                done = true;
90 
                continue;
91 
            }
92 
 
93 
            System.out.println ("-> reply: " + reply);
94 
            System.out.print ("% decode: ");
95 
            msg = kbd.readLine();
96 
        }
97 
    }
98 
}
99