Alternate version showing class modifications

projects/TcpExample2/src/tcpexample2/TcpExample2ConnectionCounting.java

+
+package tcpexample2;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * Very slightly more complex than example1. The only thing this does
+ * differently is introduce a loop into the response, so you don't
+ * have to restart the program after one response. Also, it prints
+ * out the socket pair the server sees. Run the program via telnet
+ * several times and compare the socket pairs.
+ * 
+ * telnet localhost 2317
+ * 
+ * If you're sophisticated you can contact the instructor's computer
+ * while running this program.
+ * 
+ * telnet <ipOfServersLaptop> 2317
+ * 
+ * And have him display the socket pairs he got.
+ * @author mcgredo
+ */
+public class TcpExample2ConnectionCounting 
+{
+
+    public static void main(String[] args) 
+    {
+        try
+        {
+            // ServerSocket waits for a connection from a client. 
+            // Notice that it is outside the loop; ServerSocket
+            // needs to be made only once.
+			
+			int connectionCount = 0; // state
+            
+            ServerSocket serverSocket = new ServerSocket(2317);
+
+            // 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
+				
+				connectionCount++; // got another one!
+				
+                OutputStream os = clientConnection.getOutputStream();
+                PrintStream ps = new PrintStream(os);
+
+						ps.println("This response was written by server TcpExample2"); // to remote client
+				System.out.println("This response was written by server TcpExample2"); // to server console
+                
+                // 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();
+                
+                // 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 ))
+                // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 ))
+                //
+                // Why is the first IP/port the same, while the second set has
+                // different ports?
+
+
+                System.out.println("Socket pair: (( " + localAddress.toString() + ", " + localPort + " ), ( " + 
+                        remoteAddress.toString() + ", " + remotePort + " ))");
+                
+                System.out.println("got another connection, #" + connectionCount); // report progress
+				
+                // Notice the use of flush() and close(). Without
+                // the close() to Socket object may stay open for 
+                // a while after the client has stopped needing this
+                // connection. Close() explicitly ends the connection.
+                ps.flush();
+                clientConnection.close();
+            }
+       }
+        catch(Exception e)
+        {
+            System.out.println("problem with networking: " + e);
+        }
+       
+    }
+    
+}