Merge origin/master

assignments/src/MV3500Cohort2024JulySeptember/homework2/Yu/YuHW2Client.java

+package MV3500Cohort2024JulySeptember.homework2.Yu;
+
+import java.io.*;
+import java.net.*;
+//import java.time.LocalTime; // conversion?
+
+/**
+ * @author Jin Hong Yu
+ */
+public class YuHW2Client {
+
+    /**
+     * Default constructor
+     */
+    public YuHW2Client() {
+        // default constructor
+    }
+    static String DESTINATION_HOST = "localhost";
+    static int MAX_LOOP_COUNT = 4;
+
+    /**
+     * Program invocation, execution starts here
+     *
+     * @param args command-line arguments
+     */
+    public static void main(String[] args) {
+        try {
+            System.out.println(YuHW2Client.class.getName() + " start, loop " + MAX_LOOP_COUNT + " times");
+            System.out.println("=======================================================");
+            for (int loopCount = 1; loopCount <= MAX_LOOP_COUNT; loopCount++) {
+                System.out.println(YuHW2Client.class.getName() + " creating new socket #" + loopCount + "...");
+
+                long startTime = System.currentTimeMillis();
+
+                Socket socket = new Socket(DESTINATION_HOST, 2317);
+
+                PrintStream ps = new PrintStream(socket.getOutputStream());
+                BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+
+                // Knock Knock joke sequence
+                ps.println("Knock Knock");
+                ps.flush();
+                System.out.println("Client: Knock Knock");
+
+                String serverResponse = br.readLine(); // blocks
+                System.out.println("Server: " + serverResponse);
+
+                if ("Who's there?".equals(serverResponse)) {
+                    ps.println("Hatch");
+                    ps.flush();
+                    System.out.println("Client: Hatch");
+                }
+
+                serverResponse = br.readLine();
+                System.out.println("Server: " + serverResponse);
+
+                if ("Hatch who?".equals(serverResponse)) {
+                    ps.println("God Bless You!");
+                    ps.flush();
+                    System.out.println("Client: God Bless You!");
+                }
+
+                long readTime = System.currentTimeMillis();
+                long timeLength = readTime - startTime;
+
+                System.out.println(YuHW2Client.class.getName() + ": time msec required for sequence=" + timeLength);
+                System.out.println("=======================================================");
+                socket.close();
+            }
+            System.out.println(YuHW2Client.class.getName() + " complete");
+        } catch (IOException e) {
+            System.out.println("Problem with " + YuHW2Client.class.getName() + " networking:");
+            System.out.println("Error: " + e);
+            if (e instanceof java.net.BindException) {
+                System.out.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+    }
+}

assignments/src/MV3500Cohort2024JulySeptember/homework2/Yu/YuHW2HandlerThread.java

+package MV3500Cohort2024JulySeptember.homework2.Yu;
+
+import java.io.*;
+import java.net.*;
+
+/**
+ * @author Jin Hong Yu
+ */
+public class YuHW2HandlerThread extends Thread
+{
+    /** The socket connection to a client */
+    Socket socket;
+    
+    /** 
+     * The thread constructor creates the socket from a ServerSocket, waiting for the client to connect,
+     * and passes that socket when constructing the thread responsible for handling the connection.
+     * 
+     * @param socket The socket connection handled by this thread
+     */
+    YuHW2HandlerThread(Socket socket)
+    {
+        this.socket = socket;
+    }
+    /**
+     * Program invocation and execution starts here - but is illegal and unwanted, so warn the unsuspecting user!
+     * @param args command-line arguments
+     */
+    public static void main(String[] args)
+    {
+        System.out.println ("*** YuHW2HandlerThread is not a standalone executable progam.");
+        System.out.println ("*** Please run TcpExample4DispatchServer instead... now exiting.");
+    }
+    
+    /** Handles one connection. We add an artificial slowness
+     * to handling the connection with a sleep(). This means
+     * the client won't see a server connection response for ten seconds (default).
+     */
+    // @overriding run() method in Java Thread class is deliberate
+    @Override 
+    public void run()
+    {
+    try {
+        System.out.println(YuHW2HandlerThread.class.getName() + " starting to handle a thread...");
+
+        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
+        PrintStream ps = new PrintStream(socket.getOutputStream());
+
+        // Sequence of the Knock Knock joke
+        String clientMessage = in.readLine();
+        System.out.println("Client: " + clientMessage);
+
+        if ("Knock Knock".equals(clientMessage)) {
+            ps.println("Who's there?");
+            ps.flush();
+        }
+
+        clientMessage = in.readLine();
+        System.out.println("Client: " + clientMessage);
+
+        if ("Hatch".equals(clientMessage)) {
+            ps.println("Hatch who?");
+            ps.flush();
+        }
+
+        clientMessage = in.readLine();
+        System.out.println("Client: " + clientMessage);
+
+        if ("God Bless You!".equals(clientMessage)) {
+            System.out.println("Joke sequence complete.");
+        }
+
+        socket.close(); // all clear, no longer need socket
+        System.out.println(YuHW2HandlerThread.class.getName() + " finished handling a thread, now exit.");
+    } catch(IOException e) {
+        System.out.println("Problem with " + YuHW2HandlerThread.class.getName() + " networking:");
+        System.out.println("Error: " + e);
+        if (e instanceof java.net.BindException) {
+            System.out.println("*** Be sure to stop any other running instances of programs using this port!");
+        }
+      }
+    }
+}

assignments/src/MV3500Cohort2024JulySeptember/homework2/Yu/YuHW2Server.java

+package MV3500Cohort2024JulySeptember.homework2.Yu;
+
+import java.io.IOException;
+import java.net.*;
+
+/**
+ * @author Jin Hong Yu
+ */
+public class YuHW2Server
+{
+    /** Default constructor */
+    public YuHW2Server()
+    {
+        // default constructor
+    }
+    /**
+     * Program invocation, execution starts here
+     * @param args command-line arguments
+     */
+    public static void main(String[] args)
+    {
+        try {
+            ServerSocket             serverSocket = new ServerSocket(2317);
+            Socket                   clientConnectionSocket;
+            YuHW2HandlerThread handlerThread;
+
+            int connectionCount = 0; // state variable
+
+            //System.out.println(TcpExample4DispatchServer.class.getName() + " ready to accept socket connections...");
+            while (true) // infinite loop
+            {
+                clientConnectionSocket = serverSocket.accept(); // block! until connected
+
+                connectionCount++; // unblocked, got another connection
+                
+                
+                System.out.println("=============================================================");
+                //System.out.println(TcpExample4DispatchServer.class.getName() + ".handlerThread created for connection #" + connectionCount + "...");
+                
+                // hand off this aready-created and connected socket to constructor
+                handlerThread = new YuHW2HandlerThread(clientConnectionSocket); 
+                handlerThread.start();// invokes the run() method in that object
+                //System.out.println(TcpExample4DispatchServer.class.getName() + ".handlerThread is now dispatched and running, using most recent connection...");
+                
+                // while(true) continue looping, serverSocket is still waiting for another customer client
+            }
+        } 
+        catch (IOException e) {
+            //System.out.println("Problem with " + TcpExample4DispatchServer.class.getName() + " networking:"); // describe what is happening
+            System.out.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.out.println("*** Be sure to stop any other running instances of programs using this port!");
+            }
+        }
+        System.out.println("============================================================="); // execution complete
+    }
+}