Merge pull request 'multihreading' (#1) from develop into main

Reviewed-on: neda/WS-07-Multithreading-Basics-and-Hashing#1
Reviewed-by: Hosein Asfiaee

.idea/.gitignore

@@ -0,0 +1,10 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Ignored default folder with query files
+/queries/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/compiler.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <annotationProcessing>
+      <profile name="Maven default annotation processors profile" enabled="true">
+        <sourceOutputDir name="target/generated-sources/annotations" />
+        <sourceTestOutputDir name="target/generated-test-sources/test-annotations" />
+        <outputRelativeToContentRoot value="true" />
+        <module name="WS-07-Multithreading-Basics-and-Hashing" />
+      </profile>
+    </annotationProcessing>
+  </component>
+</project>

.idea/encodings.xml

@@ -0,0 +1,7 @@
+<?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>

.idea/jarRepositories.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="RemoteRepositoriesConfiguration">
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Central Repository" />
+      <option name="url" value="https://maven.devneeds.ir/" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="central" />
+      <option name="name" value="Maven Central repository" />
+      <option name="url" value="https://repo1.maven.org/maven2" />
+    </remote-repository>
+    <remote-repository>
+      <option name="id" value="jboss.community" />
+      <option name="name" value="JBoss Community repository" />
+      <option name="url" value="https://repository.jboss.org/nexus/content/repositories/public/" />
+    </remote-repository>
+  </component>
+</project>

.idea/misc.xml

@@ -0,0 +1,12 @@
+<?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" project-jdk-name="26" project-jdk-type="JavaSDK" />
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

src/main/java/dev/Main.java

@@ -1,22 +1,34 @@
 package dev;
 
+
+import dev.model.Student;
 import dev.service.StudentManager;
 import dev.thread.StudentLoader;
 import dev.utils.FileManager;
 
+
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Scanner;
 
+
 public class Main {
 
+
     public static void main(String[] args) throws Exception {
 
+
         Scanner scanner = new Scanner(System.in);
 
-        StudentManager manager = new StudentManager();
+
+        StudentManager manager =
+                new StudentManager();
+
+
 
         while (true) {
 
+
             System.out.println("""
                     1.Load students
                     2.Search student
@@ -25,71 +37,180 @@ public class Main {
                     5.Exit
                     """);
 
+
+
             int choice = scanner.nextInt();
 
+
+
             switch (choice) {
 
+
+
                 case 1 -> {
 
-                    List<String> data = FileManager.loadStudents("students.txt");
 
-                    // TODO:
+                    List<String> data =
+                            FileManager.loadStudents("students.txt");
 
-                    // Split data into 3 parts
 
-                    List<String> part1 = null;
 
-                    List<String> part2 = null;
+                    int size = data.size();
 
-                    List<String> part3 = null;
 
-                    // TODO:
+                    int part = (int)Math.ceil(size / 3.0);
 
-                    StudentLoader t1 = null;
 
-                    StudentLoader t2 = null;
 
-                    StudentLoader t3 = null;
+                    List<String> part1 =
+                            data.subList(
+                                    0,
+                                    Math.min(part,size)
+                            );
 
-                    // TODO:
 
-                    // start()
+                    List<String> part2 =
+                            data.subList(
+                                    Math.min(part,size),
+                                    Math.min(part*2,size)
+                            );
 
-                    // join()
 
-                    // merge results
+                    List<String> part3 =
+                            data.subList(
+                                    Math.min(part*2,size),
+                                    size
+                            );
+
+
+
+                    StudentLoader t1 =
+                            new StudentLoader(part1);
+
+
+                    StudentLoader t2 =
+                            new StudentLoader(part2);
+
+
+                    StudentLoader t3 =
+                            new StudentLoader(part3);
+
+
+
+                    t1.start();
+
+                    t2.start();
+
+                    t3.start();
+
+
+
+                    t1.join();
+
+                    t2.join();
+
+                    t3.join();
+
+
+
+
+                    ArrayList<Student> finalList =
+                            new ArrayList<>();
+
+
+                    finalList.addAll(t1.getStudents());
+
+                    finalList.addAll(t2.getStudents());
+
+                    finalList.addAll(t3.getStudents());
+
+
+
+                    manager.addStudents(finalList);
+
+
+
+                    System.out.println(
+                            "Students loaded: "
+                                    + finalList.size()
+                    );
+
 
                 }
 
+
+
                 case 2 -> {
 
+
                     System.out.print("ID: ");
 
+
                     int id = scanner.nextInt();
 
-                    System.out.println(manager.searchStudent(id));
+
+
+                    Student student =
+                            manager.searchStudent(id);
+
+
+
+                    if(student != null){
+
+                        System.out.println("Found:");
+
+                        System.out.println(student);
+
+                    }
+
+                    else{
+
+                        System.out.println("Student not found.");
+
+                    }
+
 
                 }
 
+
+
                 case 3 -> {
 
+
                     System.out.print("ID: ");
 
+
                     int id = scanner.nextInt();
 
-                    boolean removed = manager.removeStudent(id);
 
-                    System.out.println(removed);
+                    System.out.println(
+                            manager.removeStudent(id)
+                    );
+
 
                 }
 
-                case 4 ->
-                        manager.printStudents();
+
+
+                case 4 -> {
+
+
+                    manager.printStudents();
+
+
+                }
+
+
 
                 case 5 -> {
+
+
                     return;
+
+
                 }
 
+
             }
 
         }

src/main/java/dev/model/Student.java

@@ -3,18 +3,11 @@ package dev.model;
 public class Student {
 
     private final int id;
-
     private final String name;
-
     private final String major;
-
     private final double gpa;
 
-    public Student(
-            int id,
-            String name,
-            String major,
-            double gpa) {
+    public Student(int id, String name, String major, double gpa) {
 
         this.id = id;
         this.name = name;
@@ -38,35 +31,35 @@ public class Student {
         return gpa;
     }
 
+
     @Override
     public int hashCode() {
 
-        // TODO:
-        // Return custom hash
-
-        // Example:
-        // return id % 97;
-
-        return 0;
+        return id % 97;
     }
 
+
     @Override
     public boolean equals(Object obj) {
 
-        // TODO:
+        if (obj == null) {
+            return false;
+        }
 
-        // Step 1:
-        // Check null
+        if (this == obj) {
+            return true;
+        }
 
-        // Step 2:
-        // Convert obj to Student
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
 
-        // Step 3:
-        // Compare IDs
+        Student other = (Student) obj;
 
-        return false;
+        return id == other.id;
     }
 
+
     @Override
     public String toString() {
 
@@ -77,5 +70,4 @@ public class Student {
                 ", gpa=" + gpa +
                 '}';
     }
-
 }

src/main/java/dev/service/StudentManager.java

@@ -4,46 +4,58 @@ import dev.model.Student;
 
 import java.util.ArrayList;
 
-
 public class StudentManager {
 
+
     private final ArrayList<Student> students = new ArrayList<>();
 
+
     public void addStudents(ArrayList<Student> newStudents) {
 
-        // TODO:
-
-        // Merge students
-
-        // Hint:
-        // addAll()
+        students.addAll(newStudents);
 
     }
 
+
     public Student searchStudent(int id) {
 
-        // TODO:
 
-        // Loop through students
+        for (Student student : students) {
+
+
+            if (student.getId() == id) {
+
+                return student;
+            }
+
+        }
 
-        // Compare IDs
 
         return null;
     }
 
+
     public boolean removeStudent(int id) {
 
-        // TODO:
 
-        // Find student
+        Student student = searchStudent(id);
+
+
+        if (student != null) {
+
+            students.remove(student);
+
+            return true;
+        }
 
-        // Remove student
 
         return false;
     }
 
+
     public void printStudents() {
 
+
         for (Student student : students) {
 
             System.out.println(student);

src/main/java/dev/thread/StudentLoader.java

@@ -1,56 +1,58 @@
 package dev.thread;
 
 
-
 import dev.model.Student;
 
 import java.util.ArrayList;
 import java.util.List;
 
+
 public class StudentLoader extends Thread {
 
-    // Assigned file lines
 
     private final List<String> lines;
 
-    // Local student storage
 
     private final ArrayList<Student> students = new ArrayList<>();
 
+
     public StudentLoader(List<String> lines) {
 
         this.lines = lines;
     }
 
+
     @Override
     public void run() {
 
-        // TODO:
-
-        /*
-        Example line:
-
-        1001,Aryan,Computer Science,3.7
-         */
 
         for (String line : lines) {
 
-            // TODO:
-            // split line
 
-            // TODO:
-            // read values
+            String[] data = line.split(",");
 
-            // TODO:
-            // create Student
 
-            // TODO:
-            // add to students list
+            int id = Integer.parseInt(data[0]);
+
+            String name = data[1];
+
+            String major = data[2];
+
+            double gpa = Double.parseDouble(data[3]);
+
+
+            Student student =
+                    new Student(id, name, major, gpa);
+
+
+            students.add(student);
 
         }
 
+
     }
 
+
     public ArrayList<Student> getStudents() {
 
         return students;

src/main/java/dev/utils/FileManager.java

@@ -1,31 +1,46 @@
 package dev.utils;
 
+
 import java.io.BufferedReader;
 import java.io.FileReader;
-
 import java.util.ArrayList;
 import java.util.List;
 
+
 public class FileManager {
 
-    public static List<String> loadStudents(String path) throws Exception {
+
+    public static List<String> loadStudents(String path)
+            throws Exception {
+
 
         List<String> lines = new ArrayList<>();
 
-        BufferedReader reader = new BufferedReader(new FileReader(path));
+
+        BufferedReader reader =
+                new BufferedReader(
+                        new FileReader(path)
+                );
+
 
         String line;
 
+
         while ((line = reader.readLine()) != null) {
 
-            // TODO:
 
-            // Add line to list
+            if (!line.isEmpty()) {
+
+                lines.add(line);
+
+            }
 
         }
 
+
         reader.close();
 
+
         return lines;
     }
 

src/main/java/lecture/multithreading/basics/JoinSimpleExample.java

@@ -25,7 +25,7 @@ public class JoinSimpleExample {
         System.out.println("The main thread waits until the worker finishes...");
 
         try {
-            worker.join(); // The main thread stops here until the worker finishes
+            worker.join();
         } catch (InterruptedException e) {
             e.printStackTrace();
         }

src/main/java/lecture/multithreading/timeout/Main.java

@@ -1,10 +1,36 @@
 package lecture.multithreading.timeout;
 
-
-
 public class Main {
-    public static void main(String[] args) {
-        // TODO
+    public static void main(String[] args) throws InterruptedException {
+
+        Thread worker = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                System.out.println("👷 Worker started...");
+                try {
+                    Thread.sleep(10000); // Runs for 10 seconds
+                } catch (InterruptedException e) {
+                    System.out.println("🛑 Worker was interrupted!");
+                }
+                System.out.println("👷 Worker finished!");
+            }
+        });
+
+        worker.start();
+
+        System.out.println("Main: waiting max 3 seconds for worker...");
+
+        // join with timeout (in milliseconds)
+        worker.join(3000);
+
+        if (worker.isAlive()) {
+            System.out.println("⏰ Timeout reached! Worker is still running.");
+            System.out.println("Main: I'm not waiting anymore, continuing...");
+        } else {
+            System.out.println("Worker finished before timeout.");
+        }
+
+        System.out.println("Main thread continues its own work now.");
     }
 }