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Sandy W
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5 files changed

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‎client/Client.java‎

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import java.util.*;
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import java.io.*;
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/**
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* @author Ikonija Bogojevic
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*
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*/
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public class Client
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{
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private static String hostName;
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private static Thread thrd = null;
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// the list of threads is kept in a linked list
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private static LinkedList<Thread> list = new LinkedList<Thread>();
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private static ListIterator<Thread> li = null;
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public static void main(String[] args) throws IOException
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{
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int menuSelection = 0;
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// load hostName from the command line arguments
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hostName = args[0];
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// if no hostname is provided, quit
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if ((hostName.equals("")) || (hostName == null))
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{
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System.out.println("User did not enter a host name. Client program exiting.");
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System.exit(1);
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}
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// until the user selects 7, the Exit option, keep looping and
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// offering the menu again after running the queries to the server
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else while (menuSelection != 7) {
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// display the menu and get the user's choice
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menuSelection = mainMenu();
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// if 7, exit program
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if (menuSelection == 7) {
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System.out.println("Quitting.");
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System.exit(0);
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}
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// otherwise, create threads in the linked list
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// TO-DO: add method to ask user how many threads to make
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// for now, just create 100
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for (int i = 0; i < 30; i++) {
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// make a new thread, tell it the hostname to connect to
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// and the command to run
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thrd = new Thread(new ClientThread(hostName, menuSelection));
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thrd.start(); // start the thread
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list.add(thrd); // add the thread to the end of the linked list
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}
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for (int i = 0; i < 30; i++) {
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try {
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list.get(i).join();
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} catch (InterruptedException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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}
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} // end while
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}//end main
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//----------------------------------------------------------------------------
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public static int mainMenu()
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{
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int menuSelection = 0;
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System.out.println("The menu provides the following choices to the user: ");
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System.out.println("1. Host current Date and Time \n2. Host uptime\n"
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+ "3. Host memory use \n4. Host Netstat \n5. Host current users "
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+ "\n6. Host running processes \n7. Quit ");
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System.out.println("Please provide number corresponding to the action you want to be performed:");
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Scanner sc = new Scanner(System.in);
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menuSelection = sc.nextInt();
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System.out.println("Running command: " + menuSelection);
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return menuSelection;
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}//end mainMenu
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}

‎client/ClientThread.java‎

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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.PrintWriter;
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import java.net.Socket;
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import java.net.UnknownHostException;
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public class ClientThread extends Thread {
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int menuSelection;
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String hostName;
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private static Socket socket = null;
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ClientThread(String hostName, int menuSelection) {
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this.menuSelection = menuSelection;
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this.hostName = hostName;
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}
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public void run() {
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PrintWriter out = null;
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BufferedReader in = null;
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try
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{
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//creates a new Socket object and names it socket.
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//Establishes the socket connection between the client & server
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//name of the machine & the port number to which we want to connect
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socket = new Socket(hostName, 4000);
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System.out.print("Establishing connection.");
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out = new PrintWriter(socket.getOutputStream(), true);//opens a PrintWriter
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//on the socket
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//opens a BufferedReader on the socket
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in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
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System.out.println("\nRequesting output for the '" + menuSelection + "' command from " + hostName);
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// send the command to the server
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out.println(Integer.toString(menuSelection));
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out.flush();
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System.out.println("Sent output");
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// read the command from the server
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String outputString = "hi";
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while (((outputString = in.readLine()) != null) && (!outputString.equals("END_MESSAGE"))) {
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System.out.println(outputString);
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System.out.println("Input read");
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}
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System.out.println("closing");
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try {
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sleep(500);
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} catch (InterruptedException e) {
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// TODO Auto-generated catch block
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e.printStackTrace();
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}
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out.close();
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in.close();
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socket.close();
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}
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catch (UnknownHostException e)
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{
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System.err.println("Unknown host: " + e);
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System.exit(1);
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}
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catch (IOException e)
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{
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e.printStackTrace();
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}
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}
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}

‎server/CommandExecutor.java‎

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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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/*
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* Class containing methods for taking the command string (a string with a digit 1-6)
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* received from the server and converting that into its respective Linux shell command,
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* then executing it and returning the results.
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*/
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public class CommandExecutor {
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/**
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* Runs the shell command after first using parseCommand() to determine which
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* command to run.
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*
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* @param commandString A string containing a single digit, 1-6;
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* @return A string containing the results of the shell command.
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*/
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static String run(String commandString) {
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String result = "";
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String line;
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try {
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Process child = Runtime.getRuntime().exec(parseCommand(commandString));
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BufferedReader output = new BufferedReader(new InputStreamReader(child.getInputStream()));
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while ((line = output.readLine()) != null) {
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result = result.concat(line);
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result = result.concat("\n");
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}
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result = result.concat("\n");
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result = result.concat("END_MESSAGE");
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output.close();
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} catch (IOException e) {
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e.printStackTrace();
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}
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return result;
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}
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/**
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* Converts the digit string into its respective shell command.
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*
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* @param inputString A string containing a single digit, 1-6;
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* @return
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*/
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static String parseCommand(String inputString) {
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int inputInt = Integer.parseInt(inputString);
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String commandString = "";
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switch (inputInt) {
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// Date
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case 1:
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commandString = "date";
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break;
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// Uptime
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case 2:
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commandString = "uptime";
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break;
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// Memory use
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case 3:
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commandString = "free";
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break;
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// netstat
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case 4:
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commandString = "netstat";
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break;
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// current users
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case 5:
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commandString = "who";
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break;
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// running processes
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case 6:
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commandString = "ps -e";
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break;
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}
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return commandString;
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}
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}

‎server/Server.java‎

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import java.io.IOException;
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import java.net.ServerSocket;
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import java.net.Socket;
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import java.util.ArrayList;
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import java.util.concurrent.atomic.AtomicInteger;
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public class Server {
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/**
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* @param args
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*/
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public static void main(String[] args) {
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AtomicInteger numThreads = new AtomicInteger(0);
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// the list of threads is kept in a linked list
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ArrayList<Thread> list = new ArrayList<Thread>();
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try {
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ServerSocket socket = new ServerSocket(4000);
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System.out.println("Server listening on port 4000");
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while(true) {
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Socket client = socket.accept();
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Thread thrd = new Thread(new ServerThread(client));
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list.add(thrd);
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thrd.start();
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numThreads.incrementAndGet();
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System.out.println("Thread " + numThreads.get() + " started.");
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}
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}
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catch (IOException ioe){
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ioe.printStackTrace();
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}
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}
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}

‎server/ServerThread.java‎

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import java.io.BufferedReader;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.io.PrintWriter;
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import java.net.Socket;
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import java.util.concurrent.atomic.AtomicInteger;
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public class ServerThread extends Thread {
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Socket client = null;
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public ServerThread(Socket client) {
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this.client = client;
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}
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public void run() {
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System.out.print("Accepted connection. ");
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try {
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PrintWriter out = new PrintWriter(client.getOutputStream(), true);
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BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
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System.out.print("Reader and writer created. ");
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String inString = in.readLine();
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System.out.println("Read command " + inString);
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String outString = CommandExecutor.run(inString);
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System.out.println("Server sending: " + outString);
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out.print(outString);
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out.flush();
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out.close();
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in.close();
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client.close();
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System.out.println("Output closed.");
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}
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catch (IOException e) {
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e.printStackTrace();
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}
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}
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}

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