I'm trying to illustrate the Nagle algorithm in a simple client-server program. But I can't quite figure it out, or get it to be printed to me clearly.
In my example, the client just generates int's from 1 to 1024 and sends these to the server. The server just converts these int's to a hex string and sends them back to the client.
Pretty much everything i change ends up with the same results. The int's are sent and resent in blocks of 256 int's.. I tried setTcpNoDelay(true) on both sides to see a change but this gives the same result in my console. (but not in wireshark, i see a big difference in amount of packets sent between server and client) But my goal is to be able to see it in the console, I'm guessing there is some buffer of ObjectOutputStream or similar holding everything up?
When I change output = new PrintWriter(client.getOutputStream(), true) to false (The true or false: autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer) my server does not give any output back to the client anymore.
Basically my goal is to just give true or false with server and/or client as an argument to set the TcpNoDelay, when started, to clearly see the difference in input/output in the console. I'm not sure about everything used so any help to clear this out is welcome.
The server:
package Networks.Nagle;
import java.io.*;
import java.net.*;
import java.util.*;
public class NagleDemoServer
{
private static ServerSocket serverSocket;
private static final int PORT = 1234;
public static void main(String[] args) throws IOException
{
int received = 0;
String returned;
ObjectInputStream input = null;
PrintWriter output = null;
Socket client;
try
{
serverSocket = new ServerSocket(PORT);
System.out.println("\nServer started...");
}
catch (IOException ioEx)
{
System.out.println("\nUnable to set up port!");
System.exit(1);
}
while(true)
{
client = serverSocket.accept();
client.setTcpNoDelay(true);
System.out.println("\nNew client accepted.\n");
try
{
input = new ObjectInputStream(client.getInputStream());
output = new PrintWriter(client.getOutputStream(), true);
while( true )
{
received = input.readInt();
returned = Integer.toHexString(received);
System.out.print(" " + received);
output.println(returned.toUpperCase());
}
}
catch(EOFException eofEx)
{
output.flush();
System.out.println("\nEnd of client data.\n");
}
catch(SocketException sEx)
{
System.out.println("\nAbnormal end of client data.\n");
}
catch(IOException ioEx)
{
ioEx.printStackTrace();
}
input.close();
output.close();
client.close();
System.out.println("\nClient closed.\n");
}
}
}
The client:
package Networks.Nagle;
import java.io.*;
import java.net.*;
import java.util.*;
public class NagleDemoClient
{
private static InetAddress host;
private static final int PORT = 1234;
public static void main(String[] args)
{
Socket socket = null;
try
{
host = InetAddress.getByName("localhost");
socket = new Socket(host, PORT);
socket.setTcpNoDelay(true);
socket.setSendBufferSize(64);
System.out.println("Send Buffer: " + socket.getSendBufferSize());
System.out.println("Timeout: " + socket.getSoTimeout());
System.out.println("Nagle deactivated: " + socket.getTcpNoDelay());
}
catch(UnknownHostException uhEx)
{
System.out.println("\nHost ID not found!\n");
System.exit(1);
}
catch(SocketException sEx)
{
sEx.printStackTrace();
}
catch(IOException ioEx)
{
ioEx.printStackTrace();
}
NagleClientThread client = new NagleClientThread(socket);
NagleReceiverThread receiver = new NagleReceiverThread(socket);
client.start();
receiver.start();
try
{
client.join();
receiver.join();
socket.close();
}
catch(InterruptedException iEx)
{
iEx.printStackTrace();
}
catch(IOException ioEx)
{
ioEx.printStackTrace();
}
System.out.println("\nClient finished.");
}
}
class NagleClientThread extends Thread
{
private Socket socket;
public NagleClientThread(Socket s)
{
socket = s;
}
public void run()
{
try
{
ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
for( int i = 1; i < 1025; i++)
{
output.writeInt(i);
sleep(10);
}
output.flush();
sleep(1000);
output.close();
}
catch(IOException ioEx)
{
ioEx.printStackTrace();
}
catch(InterruptedException iEx)
{
iEx.printStackTrace();
}
}
}
class NagleReceiverThread extends Thread
{
private Socket socket;
public NagleReceiverThread(Socket s)
{
socket = s;
}
public void run()
{
String response = null;
BufferedReader input = null;
try
{
input = new BufferedReader(
new InputStreamReader(socket.getInputStream()));
try
{
while( true )
{
response = input.readLine();
System.out.print(response + " ");
}
}
catch(Exception e)
{
System.out.println("\nEnd of server data.\n");
}
input.close();
}
catch(IOException ioEx)
{
ioEx.printStackTrace();
}
}
}