JacksonAssignment1.java

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package MV3500Cohort2018JulySeptember.homework1;

import java.io.OutputStream;
import java.io.PrintStream;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * homework assignment
 * @author John
 */
public class JacksonAssignment1
{
    /**
     * Default constructor to silence javadoc warning
     * @see <a href="https://stackoverflow.com/questions/4488716/java-default-constructor" target="_blank">StackOverflow: Java default constructor</a>
     */
    public JacksonAssignment1 ()
    {
        // default initializations occur here
    }
    /** run the program
     * @param args command-line arguments, string parameters (unused) */
    public static void main(String[] args) {
        try {
            System.out.println("Hello invoker, this server process is now running"); // reporting for duty
			
            int popularityCount = 0; // state

            ServerSocket serverSocket = new ServerSocket(2317); // server decides here what port to listen on.
            // of interest: often client doesn't care what port it uses locally when connecting to that server port.

            // Loop, infinitely, waiting for client connections.
            // Stop the program somewhere else.
            while (true) {
                Socket clientConnection = serverSocket.accept(); // blocks! then proceeds once a connection is "accept"ed
                
                /**
                 * changed connectionCount to popularityCount
                 */
                popularityCount++;

                OutputStream os = clientConnection.getOutputStream();
                PrintStream ps = new PrintStream(os);

                        ps.println("This client response was written by server JacksonAssignment1"); // to remote client
                System.out.println("This server response was written by server JacksonAssignment1"); // to server console

                ps.println("You were connection #" + popularityCount + ", by my count");

                // Print some information locally about the Socket
                // connection. This includes the port and IP numbers
                // on both sides (the socket pair.)
                InetAddress localAddress = clientConnection.getLocalAddress();
                InetAddress remoteAddress = clientConnection.getInetAddress();

                int localPort = clientConnection.getLocalPort();
                int remotePort = clientConnection.getPort();       // remember the prior question, why are 2 ports different?

                // My socket pair connection looks like this, to localhost:
                // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54876 )) note IPv6
                // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 ))
                System.out.println("Socket pair: (( " + localAddress.toString() + ", " + localPort + " ), ( "
                        + remoteAddress.toString() + ", " + remotePort + " ))");
                
                if (popularityCount == 1){
                
                    System.out.println("Your server has received " + popularityCount + " hit"); // report progress
                }
                else {
                    System.out.println("Your server has received " + popularityCount + " hits"); // report progress
                }
                ps.flush();
                clientConnection.close();
            }
        } catch (Exception e) {
            /**
             * added to the println for fun
             */
            System.out.println("Error code: " + e);
        }
    }
}