Adding timeout to DatagramSocket - receive()

Question

I need to create a 10 second timeout on this part of the code

DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
socket.receive(getack);

I need it to listed for incoming packets for 10s if it receives a packet before 10s it would skip down to if statement in case it reaches 10s it would jump down to else and resend the packet. Is this possible and how could i do this iam pretty new to this.

private static void sendDATA() {
    outgoing = new byte[512]; // Empty array
    try {
        ByteBuffer sDATA = ByteBuffer.allocate(516);
        // 512 - 2 byte opcode, 2 byte block #, 512 data

        DatagramPacket data = new DatagramPacket(outgoing, outgoing.length, InetAddress.getByName(clientip), clientport);
        InputStream fis = new FileInputStream(new File(FILE));

        int a;
        int block = 1; 

        while((a = fis.read(outgoing,0,512)) != -1)
        {
            data.setLength(a);
            sDATA.put((byte)3);
            sDATA.put((byte)block);
            sDATA.put(outgoing);
            socket.send(data); 

            while(true) {
                DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
                socket.receive(getack);

                if(incoming[0] == 3 && incoming[1] == block) {
                    break;
                } else {
                    socket.send(data);
                }
            }

        }       
    } catch (Exception e) {

    }

}

sebastian · Accepted Answer · 2012-09-11T06:02:29.830

43

That should work for your example.

socket.setSoTimeout(10000);
while(true) {
    DatagramPacket getack = new DatagramPacket(incoming, incoming.length);
    try {
        socket.receive(getack);
    } catch (SocketTimeoutException e) {
       // resend
       socket.send(data);
       continue;
    }
    // check received data...
}

edited Sep 11 '12 at 06:02

answered Sep 11 '12 at 05:49

sebastian

2,427
4
32
37

Hm i looked at that but i was wondering if that will work like i meant. Will this work in the principle where if something is received before 10s skip to if and if timeout is reached then skip to else ? – Sterling Duchess Sep 11 '12 at 05:55
Also do i put this before or after getack = DatagramPacket(); – Sterling Duchess Sep 11 '12 at 05:56
@kellax I've made an edit to my post. You have to set the timeout before calling receive. – sebastian Sep 11 '12 at 06:03
@Kellax If data is received the timeout exception isn't thrown. Surely this is obvious? – user207421 Sep 11 '12 at 06:08

score 4 · Answer 2 · answered Dec 09 '14 at 08:00

4

socket.setSoTimeout(10000);
socket.receive(getack);
socket.setSoTimeout(0);

answered Dec 09 '14 at 08:00

Bartosz Konkol

41
2

1

@Rizier123 : I don't speak good English (I'm from Polish), so I gave only code. This can be used instead of same the 'socket.receive(getack);'. – Bartosz Konkol Dec 10 '14 at 12:30

Adding timeout to DatagramSocket - receive()

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