TestClient.java

/* compile: javac TestClient.java
 * run: java TestClient host port
 */
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;

public class TestClient {

    static final int MAX_PAYLOAD_SIZE = 128;
    static final char PROTOCOL_VERSION = 0x7D;
    static final int JAVA_CLIENT_ID = 0x01020304;

    static int pack(char buf[], char v, short t, long c)
    {
        buf[0] = v;
        buf[1] = (char)((t >> 8) & 0xFF);
        buf[2] = (char)((t >> 0) & 0xFF);

        buf[3] = (char)((c >> 24) & 0xFF);
        buf[4] = (char)((c >> 16) & 0xFF);
        buf[5] = (char)((c >> 8) & 0xFF);
        buf[6] = (char)((c >> 0) & 0xFF);
        return 7;
    }

    static char random_char()
    {
        final int min_char = 1;
        final int max_char = 255;

        return (char) (min_char + (Math.random() * (max_char - min_char) + min_char));
    }
    public static void main(String[] args) throws IOException {

        if( args.length < 2)
        {
            System.out.printf("Usage: java TestClient.class server port", args[0]);
            return;
        }
        String host = args[0];
        int port = Integer.parseInt(args[1]);
        Socket s = new Socket(host, port);
        BufferedWriter outp =
            new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));


        char buf[] = new char[MAX_PAYLOAD_SIZE];

        for(short payload_size = 2; payload_size < MAX_PAYLOAD_SIZE; ++payload_size)
        {
            final short message_type = payload_size;
            final int header_size = pack(buf, PROTOCOL_VERSION, message_type, JAVA_CLIENT_ID);
            final int full_size = header_size + payload_size;

            outp.write(buf, 0, header_size);


            System.out.printf("sending message of size %d\n", full_size);

            int bytes_sent = 0;

            while(bytes_sent < payload_size)
            {
                int sending_size = Math.min(payload_size, buf.length);
                for(int pos = 0; pos < sending_size-1; ++pos)
                {
                    buf[pos] = random_char();
                }
                buf[sending_size-1] = '\0';
                outp.write(buf, 0, sending_size);
                bytes_sent += sending_size;
            }
            outp.flush();

        }
        s.close();
        System.exit(0);
    }
}