Clean final upload of RMI project

.gitignore

+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store
\ No newline at end of file

.idea/.gitignore

+# Default ignored files
+/shelf/
+/workspace.xml

.idea/encodings.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding">
+    <file url="file://$PROJECT_DIR$/src/main/java" charset="UTF-8" />
+    <file url="file://$PROJECT_DIR$/src/main/resources" charset="UTF-8" />
+  </component>
+</project>
\ No newline at end of file

.idea/misc.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="MavenProjectsManager">
+    <option name="originalFiles">
+      <list>
+        <option value="$PROJECT_DIR$/pom.xml" />
+      </list>
+    </option>
+  </component>
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="17" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>
\ No newline at end of file

.idea/vcs.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file

README.md

+# RMI-HW
+

pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>server</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    <dependencies>
+
+        <dependency>
+            <groupId>org.xerial</groupId>
+            <artifactId>sqlite-jdbc</artifactId>
+            <version>3.36.0.3</version>
+        </dependency>
+
+    </dependencies>
+
+</project>
\ No newline at end of file

src/main/java/org/example/Main.java

+package org.example;
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("Hello world!");
+    }
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Client/Client.java

+package org.example.Quiz.Client;
+
+import org.example.Quiz.Shared.IQuizClient;
+import org.example.Quiz.Shared.IQuizServer;
+
+import java.rmi.registry.LocateRegistry;
+import java.rmi.registry.Registry;
+import java.util.Scanner;
+
+public class Client {
+
+    private static String currentQuestion = "";
+
+    public static void main(String[] args) {
+        try {
+            Registry registry = LocateRegistry.getRegistry("localhost", 1099);
+
+            IQuizServer serverStub = (IQuizServer) registry.lookup("QuizService");
+
+            IQuizClient clientCallbackObject = new QuizClientImpl();
+
+            Scanner scanner = new Scanner(System.in, "UTF-8");
+            System.out.print("Please enter your name:");
+            String studentName = scanner.nextLine();
+
+            serverStub.registerClient(clientCallbackObject, studentName);
+            System.out.println("...Registered successfully, " + studentName + "!");
+
+            String choice = "";
+            while (true) {
+                System.out.println("\n---Options menu---");
+                System.out.println("1. Request a new question");
+                System.out.println("2. Submit an answer");
+                System.out.println("Type 'exit' to exit the program");
+                System.out.print("Choose (1 or 2): ");
+
+                choice = scanner.nextLine();
+
+                if (choice.equalsIgnoreCase("Exit")) {
+                    break;
+                }
+
+                switch (choice) {
+                    case "1":
+                        currentQuestion = serverStub.getQuestion(studentName);
+                        System.out.println("\n>>> New question: " + currentQuestion);
+                        break;
+                    case "2":
+                        if (currentQuestion.isEmpty()) {
+                            System.out.println("!!! You must ask a question first (option 1)");
+                            continue;
+                        }
+                        System.out.print(">>> Enter your answer to the question: ");
+                        String answer = scanner.nextLine();
+
+                        String feedback = serverStub.submitAnswer(studentName, answer);
+
+                        System.out.println("\n--- Answer result---");
+                        System.out.println(feedback);
+
+                        currentQuestion = "";
+                        break;
+                    default:
+                        System.out.println("!!! Wrong selection, please enter 1 or 2.");
+                        break;
+                }
+            }
+
+            System.out.println("Thank you ");
+            System.exit(0);
+
+        } catch (Exception e) {
+            System.err.println("!!! A client error occurred!!!");
+            if (e instanceof java.rmi.NotBoundException) {
+                System.err.println("!!! The server (QuizService) cannot be found. Is the server running?");
+            }
+            e.printStackTrace();
+        }
+    }
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Client/QuizClientImpl.java

+package org.example.Quiz.Client;
+
+import org.example.Quiz.Shared.IQuizClient;
+import java.rmi.RemoteException;
+import java.rmi.server.UnicastRemoteObject;
+import java.util.List;
+
+
+public class QuizClientImpl extends UnicastRemoteObject implements IQuizClient {
+
+    public QuizClientImpl() throws RemoteException {
+        super();
+    }
+
+    @Override
+    public void notifyLeaderboardUpdate(List<String> leaderboard) throws RemoteException {
+        System.out.println("\\n\\n==== Update the leaderboard ===");
+        if (leaderboard.isEmpty()) {
+            System.out.println(" (There are no leaderboards currently)");
+        } else {
+            for (String entry : leaderboard) {
+                System.out.println("   " + entry);
+            }
+        }
+        System.out.println("==============================\n");
+        System.out.print("Select (1: Ask a question, 2: Send an answer): ");
+    }
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Server/QuizServerImpl.java

+package org.example.Quiz.Server;
+
+
+import org.example.Quiz.Client.QuizClientImpl;
+import org.example.Quiz.Shared.IQuizClient;
+import org.example.Quiz.Shared.IQuizServer;
+
+import java.rmi.RemoteException;
+import java.rmi.server.UnicastRemoteObject;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+
+public class QuizServerImpl extends UnicastRemoteObject implements IQuizServer {
+
+
+    private final Map<String, String> questions;
+
+
+    private final Map<String, Integer> studentScores;
+
+
+    private final Map<String, IQuizClient> connectedClients;
+
+
+    public QuizServerImpl() throws RemoteException {
+        super();
+
+
+        questions = new ConcurrentHashMap<>();
+        studentScores = new ConcurrentHashMap<>();
+        connectedClients = new ConcurrentHashMap<>();
+
+
+        questions.put("What is the capital of Jordan?", "Amman");
+        questions.put("How many continents are there in the world?", "7");
+        questions.put("What color is the sky on a clear day?", "blue");
+        questions.put("2 + 2 = ?", "4");
+    }
+
+
+    @Override
+    public void registerClient(IQuizClient clientStub, String studentName) throws RemoteException {
+        System.out.println("...New customer registration: " + studentName);
+
+        studentScores.put(studentName, 0);
+
+        connectedClients.put(studentName, clientStub);
+
+        System.out.println("... has been registered " + studentName + ". Number of clients now: " + connectedClients.size());
+
+        updateAndNotifyLeaderboard();
+    }
+
+    @Override
+    public void registerClient(QuizClientImpl clientStub, String studentName) throws RemoteException {
+
+    }
+
+    @Override
+    public String getQuestion(String studentName) throws RemoteException {
+        System.out.println("... Student " + studentName + "He asks a question");
+
+
+        List<String> questionList = new ArrayList<>(questions.keySet());
+
+
+        Collections.shuffle(questionList);
+
+
+        return questionList.get(0);
+    }
+
+    @Override
+    public String submitAnswer(String studentName, String answer) throws RemoteException {
+        System.out.println("...student" + studentName + "Send answer:" + answer);
+
+
+        String correctAnswer = questions.get("What is the capital of Jordan?");
+
+        boolean isCorrect = false;
+        if (questions.containsValue(answer.trim())) {
+            isCorrect = true;
+        }
+
+        if (isCorrect) {
+
+            int currentScore = studentScores.get(studentName);
+            studentScores.put(studentName, currentScore + 1);
+
+
+            updateAndNotifyLeaderboard();
+
+            return "Correct answer! Your current score is: " + (currentScore + 1);
+        } else {
+
+            return "Wrong answer. Try again.";
+        }
+    }
+
+
+
+
+    private void updateAndNotifyLeaderboard() {
+        System.out.println("...The leaderboard is being updated...");
+
+
+        List<Map.Entry<String, Integer>> sortedScores = new ArrayList<>(studentScores.entrySet());
+
+
+        sortedScores.sort((o1, o2) -> o2.getValue().compareTo(o1.getValue()));
+
+
+        List<String> leaderboard = new ArrayList<>();
+        int count = 0;
+        for (Map.Entry<String, Integer> entry : sortedScores) {
+            if (count >= 3) break;
+
+            leaderboard.add((count + 1) + ". " + entry.getKey() + " (" + entry.getValue() + " point)");
+            count++;
+        }
+
+
+        System.out.println("... Send notice to " + connectedClients.size() + " client");
+
+        for (IQuizClient client : connectedClients.values()) {
+            try {
+                client.notifyLeaderboardUpdate(leaderboard);
+            } catch (RemoteException e) {
+
+                System.err.println("...Error sending a notification to a client: " + e.getMessage());
+
+            }
+        }
+    }
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Server/Server.java

+package org.example.Quiz.Server;
+
+import java.rmi.registry.LocateRegistry;
+import java.rmi.registry.Registry;
+
+public class Server {
+    public static void main(String[] args) {
+        try {
+            QuizServerImpl quizServer = new QuizServerImpl();
+
+            Registry registry = LocateRegistry.createRegistry(1099);
+
+            registry.rebind("QuizService", quizServer);
+
+            System.out.println("===================================");
+            System.out.println("  >>> Quiz Server is Ready <<<  ");
+            System.out.println("... Waiting for client connections on port 1099");
+            System.out.println("===================================");
+
+        } catch (Exception e) {
+            System.err.println("!!! An error occurred while running the Server !!!");
+            e.printStackTrace();
+        }
+    }
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Shared/IQuizClient.java

+package org.example.Quiz.Shared;
+
+import java.rmi.Remote;
+import java.rmi.RemoteException;
+import java.util.List;
+
+
+public interface IQuizClient extends Remote {
+
+
+
+    void notifyLeaderboardUpdate(List<String> leaderboard) throws RemoteException;
+}
\ No newline at end of file

src/main/java/org/example/Quiz/Shared/IQuizServer.java

+package org.example.Quiz.Shared;
+
+import org.example.Quiz.Client.QuizClientImpl;
+
+import java.rmi.Remote;
+import java.rmi.RemoteException;
+
+public interface IQuizServer extends Remote {
+
+
+    void registerClient(IQuizClient clientStub, String studentName) throws RemoteException;
+
+    void registerClient(QuizClientImpl clientStub, String studentName) throws RemoteException;
+
+    String getQuestion(String studentName) throws RemoteException;
+
+    String submitAnswer(String studentName, String answer) throws RemoteException;
+}
\ No newline at end of file