documentation improvements

examples/src/UdpMulticastExamples/UdpSender.java

@@ -20,10 +20,12 @@ public class UdpSender
 {
     // System properties: https://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html
     public static final String            MY_NAME = System.getProperty("user.name"); // guru incantation   8)
-    public static final int          SENDING_PORT = 1414;
+//  public static final int          SENDING_PORT = 1414; // not needed, can let system choose an open local port
     public static final int        RECEIVING_PORT = 1415;
     public static final int TOTAL_PACKETS_TO_SEND = 100;
-    public static final String   DESTINATION_HOST = "localhost"; // localhost 127.0.0.1 or argon 10.1.105.1
+    
+    // here is what we need for lab comms
+    public static final String   DESTINATION_HOST = "10.1.105.16"; // localhost 127.0.0.1 or argon 10.1.105.1 or 10.1.105.1 or whatever
     
     @SuppressWarnings("SleepWhileInLoop")
     public static void main(String[] args) throws IOException 
@@ -32,7 +34,7 @@ public class UdpSender
         DataOutputStream  dos = null;
         int   packetID = 0;     // counter variable to send in packet
         float    value = -1.0f; // unreachable value is good sentinel to ensure expected changes occur
-        String message = "Hello MV3500"; // no really
+        String message = MY_NAME + " says Hello MV3500"; // no really
         String padding = new String();
         
         try
@@ -41,7 +43,7 @@ public class UdpSender
             System.out.println(UdpSender.class.getName() + " started...");
             
             // Create a UDP socket
-            udpSocket = new DatagramSocket(SENDING_PORT);
+            udpSocket = new DatagramSocket(); // let system assign output port, then SENDING_PORT not needed
             
             // Put together a message with binary content. "ByteArrayOutputStream"
             // is a java.io utility that lets us put together an array of binary
@@ -82,6 +84,7 @@ public class UdpSender
                 byteArray = baos.toByteArray();    // OK so go get the flushed result...
                 datagramPacket.setData(byteArray); // and put it in the packet...
                 udpSocket.send(datagramPacket);    // and send it away. boom gone, nonblocking.
+//              System.out.println("udpSocket output port=" + udpSocket.getLocalPort()); // diagnostic tells what port was chosen by system
                 
                 if  (isPacketIdEvenParity)
                      padding = " ";