Merge origin/master

assignments/ReportingForDuty.md

 ## Reporting For Duty
 
-Everyone in the course is hereby requested to make a change to this file.  This confirms your ability to use Netbeans and your gitlab.nps.edu account.
+Everyone in the course is hereby requested to make a change to this file.  This confirms your ability to use NetBeans and your gitlab.nps.edu account.
 
 Be sure to *git update* before, and be sure to *git commit* and *git push* after!
 
@@ -18,6 +18,16 @@ More information on your use of Git is in the parent directory [README.md](../..
 
 - Dom Hittner
 
+- Nick Hittner
+
+- Matt Robinson
+
+- Alex Fisher
+
+--John Morris
+
+- Max Schlessel
+
 ### 2020
 
 - Bernd Weissenberger

assignments/src/MV3500Cohort2021JulySeptember/homework1/FisherTCPExample1Telnet.java

+package MV3500Cohort2021JulySeptember.homework1;
+
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.net.ServerSocket;
+import java.net.Socket;
+
+/**
+ *
+ * @author adfis
+ */
+
+
+public class FisherTCPExample1Telnet {
+    public static void main(String[] args) 
+    {
+        try
+        {
+            System.out.println("TcpExample1Telnet has started and is waiting for a connection.");
+            System.out.println("  help: https://savage.nps.edu/Savage/developers.html#telnet");
+            System.out.println("  enter (telnet localhost 2317) or (nc localhost 2317)..." );
+			
+            // The ServerSocket waits for a connection from a client.
+            // It returns a Socket object when the connection occurs.
+            ServerSocket serverSocket = new ServerSocket(2317);
+            
+            // Use Java io classes to write text (as opposed to
+            // unknown bytes of some sort) to the client
+            
+            // The Socket object represents the connection between
+            // the server and client, including a full duplex connection
+            try (Socket clientConnection = serverSocket.accept()) {
+                // Use Java io classes to write text (as opposed to
+                // unknown bytes of some sort) to the client
+                OutputStream os = clientConnection.getOutputStream();
+                PrintStream ps = new PrintStream(os);
+                
+                ps.println("Client response was written by Alex' server TcpExample1."); // to remote clientnc
+                ps.println("We are crushing this assignment, good work.");
+                System.out.println("Server response was written by Alex' server TcpExample1."); // to server console
+                System.out.println("SUCCESS!");
+
+                // "flush()" in important in that it forces a write
+                // across what is in fact a slow connection
+                ps.flush();
+            }
+            System.out.println("TcpExample1 completed successfully.");
+        }
+        catch(IOException e)
+        {
+            System.err.println("Problem with TcpExample1Telnet networking:"); // describe what is happening
+            System.err.println("Error: " + e);
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            
+            // brute force exception checking, can be brittle if exception message changes
+            // if (e.getMessage().equals("Address already in use: NET_Bind")) 
+            if (e instanceof java.net.BindException)
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+        }
+    }
+}
+

assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Client.java

+package MV3500Cohort2021JulySeptember.homework1;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * This is Assignment 1 where I have modified the given code from TCPExample3Client
+ * -sleep time has been extended to give more time in between loops
+ * -Initial print line has been altered to reflect assingnment 1
+ * -Loop only runs a finite number of times ,10.
+ * Before, we always used telnet (netcat) to connect to the server. Here we are 
+ * now writing our own program to do the connection.
+ *
+ * As you will see, when we run this after we start the server we will see the
+ * same string telnet printed, sent by the server. The output at the server will
+ * show different socket pairs for each time the loop iterates.
+ *
+ * @author mcgredo
+ * @author brutzman
+ */
+public class KeevenTCPExample3Client {
+
+    /** IPv6 String constant for localhost address, similarly IPv4 127.0.0.1
+     * @see <a href="https://en.wikipedia.org/wiki/localhost">https://en.wikipedia.org/wiki/localhost</a>
+     * @see <a href="https://en.wikipedia.org/wiki/IPv6_address">https://en.wikipedia.org/wiki/IPv6_address</a> 
+     */
+    public final static String LOCALHOST = "0:0:0:0:0:0:0:1";
+
+    /**
+     * Program invocation, execution starts here
+     * @param args command-line arguments
+     */
+    public static void main(String[] args) throws InterruptedException {
+        
+        // Local variables/fields
+        Socket socket = null;
+        InputStream is;
+        Reader isr;
+        BufferedReader br;
+        String serverMessage;
+        int clientLoopCount = 0;
+        int numbLoops = 10;
+        
+        try {
+            while (clientLoopCount < numbLoops)
+            {
+                clientLoopCount++; // increment at beginning of loop for reliability
+                System.out.println(KeevenTCPExample3Client.class.getName() + " creating socket...");
+
+                // We request an IP to connect to ("localhost") and
+                // port number at that IP (2317). This establishes
+                // a connection to that IP in the form of a Socket
+                // object; the server uses a ServerSocket to wait for
+                // connections.
+                socket = new Socket(LOCALHOST, 2317); // locohost?
+
+                // Now hook everything up (i.e. set up the streams), Java style:
+                is  = socket.getInputStream();
+                isr = new InputStreamReader(is);
+                br  = new BufferedReader(isr);
+
+                // Read a single line written by the server. We'd
+                // do things a bit differently if there were many lines to be read
+                // from the server instead of one only.
+                serverMessage = br.readLine();
+                System.out.println("======================Assignment1===========================");
+                       
+                System.out.print  ("Client loop " + clientLoopCount + ": ");
+                System.out.println("now we're talking!");
+                System.out.println("The message the server sent was: '" + serverMessage + "'");
+                // socket gets closed, either automatically/silently by this code (or possibly by the server)
+                
+                Thread.sleep(800l); // slow things down, for example 500l (long) = 500 msec
+                
+            } // end while(true) // infinite loops are dangerous, be sure to kill this process!
+        } 
+        catch (IOException e)
+        {
+            System.err.println("Problem with " + KeevenTCPExample3Client.class.getName() + " networking:"); // describe what is happening
+            System.err.println("Error: " + e);
+            
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            if (e instanceof java.net.BindException) {
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+        finally // occurs after any other activity when shutting down
+        {
+            try {
+                if (socket != null)
+                    socket.close();
+            } catch (IOException e) {}
+            
+            // program exit: tell somebody about that happening.  Likely cause: server drops connection.
+            System.out.println();
+            System.out.println(KeevenTCPExample3Client.class.getName() + " exit");
+        }
+    }
+}

assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Server.java

+package MV3500Cohort2021JulySeptember.homework1;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * This is Assignment 1 where I have modified the given code from TCPExample3Server
+ *-server response message changed
+ * 
+ * Very slightly more complex than example1, further modifying example2. 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 (nc) localhost 2317
+ *
+ * If you're sophisticated you can contact the instructor's computer while
+ * running this program.
+ *
+ *      telnet (nc) [ipNumberOfServerLaptop] 2317
+ *
+ * and have the instructor display the socket pairs received.
+ *
+ * @author mcgredo
+ * @author brutzman
+ */
+public class KeevenTCPExample3Server {
+
+    /**
+     * Program invocation, execution starts here
+     * If already compiled, can run using console in directory ../../build/classes/ by invoking \
+     *      java -classpath . TcpExamples.TcpExample3Server
+     * @param args command-line arguments
+     */
+    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.
+            System.out.println(KeevenTCPExample3Server.class.getName() + " has started..."); // it helps debugging to put this on console first
+            
+            ServerSocket serverSocket = new ServerSocket(2317);
+            OutputStream os;
+            PrintStream ps;
+            InetAddress localAddress, remoteAddress;
+            int localPort, remotePort;
+            int serverLoopCount = 0;
+
+            // Server is up and waiting (i.e. "blocked" or paused)
+            // Loop, infinitely, waiting for client connections.
+            // Stop the program somewhere else.
+            while (true) { 
+                
+                // block until connected to a client
+                try (Socket clientConnectionSocket = serverSocket.accept())
+                {
+                    serverLoopCount++; // increment at beginning of loop for reliability
+                    
+                    // Now hook everything up (i.e. set up the streams), Java style:
+                    os = clientConnectionSocket.getOutputStream();
+                    ps = new PrintStream(os);
+                    ps.println("This is response " + serverLoopCount + " produced by the server, " 
+                            + KeevenTCPExample3Server.class.getName()); // this gets sent back to client!
+                    
+                    // Print some information locally about the Socket connection.
+                    // This includes the port and IP numbers on both sides (the socket pair).
+                     localAddress = clientConnectionSocket.getLocalAddress();
+                    remoteAddress = clientConnectionSocket.getInetAddress();
+                        localPort = clientConnectionSocket.getLocalPort();
+                       remotePort = clientConnectionSocket.getPort();
+                       
+                    System.out.print ("Server loop " + serverLoopCount + ": ");
+                    
+                    // 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(KeevenTCPExample3Server.class.getName() + " socket pair showing host name, address, port:");
+                    System.out.println("  (( " + 
+                         localAddress.getHostName() + "=" +  localAddress.getHostAddress() + ", " + localPort + " ), ( " + 
+                        remoteAddress.getHostName() + "=" + remoteAddress.getHostAddress() + ", " + remotePort + " ))");
+                    
+                    if ( localAddress.getHostName().equals( localAddress.getHostAddress()) ||
+                        remoteAddress.getHostName().equals(remoteAddress.getHostAddress()))
+                        System.out.println("  note HostName matches address if host has no DNS name");
+                    
+                    // Notice the use of flush() and try w/ resources. Without
+                    // the try w/ resources the Socket object may stay open for
+                    // a while after the client has stopped needing this
+                    // connection. try w/ resources explicitly ends the connection.
+                    ps.flush();
+                    // like it or not, you're outta here!
+                }
+            }
+        } catch (IOException e) {
+            System.err.println("Problem with " + KeevenTCPExample3Server.class.getName() + " networking: " + e);
+
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            if (e instanceof java.net.BindException) {
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+    }
+}

assignments/src/MV3500Cohort2021JulySeptember/homework1/MorrisTcpExample1Telnet.java

+package MV3500Cohort2021JulySeptember.homework1;;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * The simplest possible TCP network program. It listens for
+ * a connection, from telnet (telnet localhost 2317) or a program
+ * you write, which we will do later. Right now the TcpExample simply
+ * writes a string in response to a connection.
+ * 
+ * Modifying his program is the basis for Assignment 1.
+ * 
+ * Testing the running server program from telnet looks like this:
+ * 
+ * it154916:projects mcgredo$ telnet localhost 2317
+ * Trying ::1...
+ * Connected to localhost.
+ * Escape character is '^]'.
+ * This was written by the server
+ * Connection closed by foreign host.
+ * 
+ * Notice that "This was written by the server" matches 
+ * what is written by the code below, over the output stream.
+ * 
+ * After this first connection the program below drops out
+ * the bottom of the program, and does not repeat itself.
+ * The program exits.
+ * 
+ * @author mcgredo
+ * @author brutzman
+ */
+public class MorrisTcpExample1Telnet 
+{
+    /**
+     * Program invocation, execution starts here
+     * @param args command-line arguments
+     */
+    public static void main(String[] args)
+    {
+        try
+        {
+            System.out.println("TcpExample1Telnet  has started and is waiting for a connection.");
+            System.out.println("  help: https://savage.nps.edu/Savage/developers.html#telnet");
+            System.out.println("  enter (telnet localhost 2317) or (nc localhost 2317)..." );
+			
+            // The ServerSocket waits for a connection from a client.
+            // It returns a Socket object when the connection occurs.
+            ServerSocket serverSocket = new ServerSocket(2317);
+            
+            // Use Java io classes to write text (as opposed to
+            // unknown bytes of some sort) to the client
+            
+            // The Socket object represents the connection between
+            // the server and client, including a full duplex connection
+            try (Socket clientConnection = serverSocket.accept()) // wait here for a client to connect
+            {
+                // OK we got something, time to respond!
+                // Use Java io classes to write text (as opposed to
+                // unknown bytes of some sort) to the client
+                OutputStream os = clientConnection.getOutputStream();
+                PrintStream ps = new PrintStream(os);
+                
+                        ps.println("This client response was written by Johnny Smiles ");  // to remote client
+                        ps.println("MOVES 2021 Cohort is full of badassery.");
+                System.out.println("This server response was written by Johnny Smiles " ); // to server console
+
+                // "flush()" in important in that it forces a write
+                // across what is in fact a slow connection
+                ps.flush();
+            }
+            System.out.println(" completed successfully.");
+        }
+        catch(IOException e)
+        {
+            System.err.println(" Pardon the interruption, networking issue"); // describe what is happening
+            System.err.println(e);
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            
+            // brute force exception checking, can be brittle if exception message changes
+            // if (e.getMessage().equals("Address already in use: NET_Bind")) 
+            if (e instanceof java.net.BindException)
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+        }
+    }
+}

assignments/src/MV3500Cohort2021JulySeptember/homework1/README.md

 ## Homework 1: Unicast Networking
 
+Welcome everybody! This is where your homework goes.
+
 Deliverables:
 
 * Update unicast sockets sender/receiver, modifying provided code, test via telnet.

examples/src/TcpExamples/Assignment1TCPExample3ClientChange.java

+package TcpExamples;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * This is Assignment 1 where I have modified the given code from TCPExample3Client
+ * -sleep time has been extended to give more time in between loops
+ * -Initial print line has been altered to reflect assingnment 1
+ * -Loop only runs a finite number of times ,10.
+ * Before, we always used telnet (netcat) to connect to the server. Here we are 
+ * now writing our own program to do the connection.
+ *
+ * As you will see, when we run this after we start the server we will see the
+ * same string telnet printed, sent by the server. The output at the server will
+ * show different socket pairs for each time the loop iterates.
+ *
+ * @author mcgredo
+ * @author brutzman
+ */
+public class Assignment1TCPExample3ClientChange {
+
+    /** IPv6 String constant for localhost address, similarly IPv4 127.0.0.1
+     * @see <a href="https://en.wikipedia.org/wiki/localhost">https://en.wikipedia.org/wiki/localhost</a>
+     * @see <a href="https://en.wikipedia.org/wiki/IPv6_address">https://en.wikipedia.org/wiki/IPv6_address</a> 
+     */
+    public final static String LOCALHOST = "0:0:0:0:0:0:0:1";
+
+    /**
+     * Program invocation, execution starts here
+     * @param args command-line arguments
+     */
+    public static void main(String[] args) throws InterruptedException {
+        
+        // Local variables/fields
+        Socket socket = null;
+        InputStream is;
+        Reader isr;
+        BufferedReader br;
+        String serverMessage;
+        int clientLoopCount = 0;
+        int numbLoops = 10;
+        
+        try {
+            while (clientLoopCount < numbLoops)
+            {
+                clientLoopCount++; // increment at beginning of loop for reliability
+                System.out.println(Assignment1TCPExample3ClientChange.class.getName() + " creating socket...");
+
+                // We request an IP to connect to ("localhost") and
+                // port number at that IP (2317). This establishes
+                // a connection to that IP in the form of a Socket
+                // object; the server uses a ServerSocket to wait for
+                // connections.
+                socket = new Socket(LOCALHOST, 2317); // locohost?
+
+                // Now hook everything up (i.e. set up the streams), Java style:
+                is  = socket.getInputStream();
+                isr = new InputStreamReader(is);
+                br  = new BufferedReader(isr);
+
+                // Read a single line written by the server. We'd
+                // do things a bit differently if there were many lines to be read
+                // from the server instead of one only.
+                serverMessage = br.readLine();
+                System.out.println("======================Assignment1===========================");
+                       
+                System.out.print  ("Client loop " + clientLoopCount + ": ");
+                System.out.println("now we're talking!");
+                System.out.println("The message the server sent was: '" + serverMessage + "'");
+                // socket gets closed, either automatically/silently by this code (or possibly by the server)
+                
+                Thread.sleep(800l); // slow things down, for example 500l (long) = 500 msec
+                
+            } // end while(true) // infinite loops are dangerous, be sure to kill this process!
+        } 
+        catch (IOException e)
+        {
+            System.err.println("Problem with " + TcpExample3Client.class.getName() + " networking:"); // describe what is happening
+            System.err.println("Error: " + e);
+            
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            if (e instanceof java.net.BindException) {
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+        finally // occurs after any other activity when shutting down
+        {
+            try {
+                if (socket != null)
+                    socket.close();
+            } catch (IOException e) {}
+            
+            // program exit: tell somebody about that happening.  Likely cause: server drops connection.
+            System.out.println();
+            System.out.println(TcpExample3Client.class.getName() + " exit");
+        }
+    }
+}

examples/src/TcpExamples/Assignmnet1TCPExample3ServerChange.java

+package TcpExamples;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * This is Assignment 1 where I have modified the given code from TCPExample3Server
+ *-server response message changed
+ * 
+ * Very slightly more complex than example1, further modifying example2. 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 (nc) localhost 2317
+ *
+ * If you're sophisticated you can contact the instructor's computer while
+ * running this program.
+ *
+ *      telnet (nc) [ipNumberOfServerLaptop] 2317
+ *
+ * and have the instructor display the socket pairs received.
+ *
+ * @author mcgredo
+ * @author brutzman
+ */
+public class Assignmnet1TCPExample3ServerChange {
+
+    /**
+     * Program invocation, execution starts here
+     * If already compiled, can run using console in directory ../../build/classes/ by invoking \
+     *      java -classpath . TcpExamples.TcpExample3Server
+     * @param args command-line arguments
+     */
+    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.
+            System.out.println(Assignmnet1TCPExample3ServerChange.class.getName() + " has started..."); // it helps debugging to put this on console first
+            
+            ServerSocket serverSocket = new ServerSocket(2317);
+            OutputStream os;
+            PrintStream ps;
+            InetAddress localAddress, remoteAddress;
+            int localPort, remotePort;
+            int serverLoopCount = 0;
+
+            // Server is up and waiting (i.e. "blocked" or paused)
+            // Loop, infinitely, waiting for client connections.
+            // Stop the program somewhere else.
+            while (true) { 
+                
+                // block until connected to a client
+                try (Socket clientConnectionSocket = serverSocket.accept())
+                {
+                    serverLoopCount++; // increment at beginning of loop for reliability
+                    
+                    // Now hook everything up (i.e. set up the streams), Java style:
+                    os = clientConnectionSocket.getOutputStream();
+                    ps = new PrintStream(os);
+                    ps.println("This is response " + serverLoopCount + " produced by the server, " 
+                            + Assignmnet1TCPExample3ServerChange.class.getName()); // this gets sent back to client!
+                    
+                    // Print some information locally about the Socket connection.
+                    // This includes the port and IP numbers on both sides (the socket pair).
+                     localAddress = clientConnectionSocket.getLocalAddress();
+                    remoteAddress = clientConnectionSocket.getInetAddress();
+                        localPort = clientConnectionSocket.getLocalPort();
+                       remotePort = clientConnectionSocket.getPort();
+                       
+                    System.out.print ("Server loop " + serverLoopCount + ": ");
+                    
+                    // 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(TcpExample3Server.class.getName() + " socket pair showing host name, address, port:");
+                    System.out.println("  (( " + 
+                         localAddress.getHostName() + "=" +  localAddress.getHostAddress() + ", " + localPort + " ), ( " + 
+                        remoteAddress.getHostName() + "=" + remoteAddress.getHostAddress() + ", " + remotePort + " ))");
+                    
+                    if ( localAddress.getHostName().equals( localAddress.getHostAddress()) ||
+                        remoteAddress.getHostName().equals(remoteAddress.getHostAddress()))
+                        System.out.println("  note HostName matches address if host has no DNS name");
+                    
+                    // Notice the use of flush() and try w/ resources. Without
+                    // the try w/ resources the Socket object may stay open for
+                    // a while after the client has stopped needing this
+                    // connection. try w/ resources explicitly ends the connection.
+                    ps.flush();
+                    // like it or not, you're outta here!
+                }
+            }
+        } catch (IOException e) {
+            System.err.println("Problem with " + TcpExample3Server.class.getName() + " networking: " + e);
+
+            // Provide more helpful information to user if exception occurs due to running twice at one time
+            if (e instanceof java.net.BindException) {
+                System.err.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+    }
+}