Multithreading Basics and Hashing

.idea/.gitignore

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

.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="25" 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

@@ -4,19 +4,19 @@ 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 {
+    public static void main(String[] args) throws Exception
-
+    {
         Scanner scanner = new Scanner(System.in);
-
         StudentManager manager = new StudentManager();
 
-        while (true) {
+        while (true)
-
+        {
             System.out.println("""
                     1.Load students
                     2.Search student
@@ -27,73 +27,73 @@ public class Main {
 
             int choice = scanner.nextInt();
 
-            switch (choice) {
+            switch (choice)
-
+            {
-                case 1 -> {
+                case 1 ->
-
+                {
                     List<String> data = FileManager.loadStudents("students.txt");
 
-                    // TODO:
+                    if (data.isEmpty())
+                    {
+                        System.out.println("No data found in file.");
+                        break;
+                    }
 
-                    // Split data into 3 parts
+                    // TODO: Split data into 3 parts
+                    int totalSize = data.size();
+                    int chunkSize = (int) Math.ceil(totalSize / 3.0);
 
-                    List<String> part1 = null;
+                    List<String> part1 = data.subList(0, Math.min(chunkSize, totalSize));
+                    List<String> part2 = data.subList(Math.min(chunkSize, totalSize), Math.min(2 * chunkSize, totalSize));
+                    List<String> part3 = data.subList(Math.min(2 * chunkSize, totalSize), totalSize);
 
-                    List<String> part2 = null;
+                    StudentLoader t1 = new StudentLoader(part1);
+                    StudentLoader t2 = new StudentLoader(part2);
+                    StudentLoader t3 = new StudentLoader(part3);
 
-                    List<String> part3 = null;
+                    t1.start();
+                    t2.start();
+                    t3.start();
 
-                    // TODO:
+                    t1.join();
+                    t2.join();
+                    t3.join();
 
-                    StudentLoader t1 = null;
+                    manager.addStudents(t1.getStudents());
-
+                    manager.addStudents(t2.getStudents());
-                    StudentLoader t2 = null;
+                    manager.addStudents(t3.getStudents());
-
-                    StudentLoader t3 = null;
-
-                    // TODO:
-
-                    // start()
-
-                    // join()
-
-                    // merge results
 
+                    System.out.println("Students loaded successfully using 3 threads.");
                 }
 
-                case 2 -> {
+                case 2 ->
-
+                {
                     System.out.print("ID: ");
-
                     int id = scanner.nextInt();
-
+                    var student = manager.searchStudent(id);
-                    System.out.println(manager.searchStudent(id));
+                    if (student != null)
-
+                    {
+                        System.out.println("Found: " + student);
+                    }
+                    else
+                    {
+                        System.out.println("Student not found.");
+                    }
                 }
 
-                case 3 -> {
+                case 3 ->
-
+                {
                     System.out.print("ID: ");
-
                     int id = scanner.nextInt();
-
                     boolean removed = manager.removeStudent(id);
-
+                    System.out.println("Removed: " + removed);
-                    System.out.println(removed);
-
                 }
 
                 case 4 ->
                         manager.printStudents();
 
-                case 5 -> {
+                case 5 -> {return;}
-                    return;
-                }
-
             }
-
         }
-
     }
-
 }

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

@@ -1,13 +1,10 @@
 package dev.model;
 
-public class Student {
+public class Student
-
+{
     private final int id;
-
     private final String name;
-
     private final String major;
-
     private final double gpa;
 
     public Student(
@@ -39,37 +36,22 @@ public class Student {
     }
 
     @Override
-    public int hashCode() {
+    public int hashCode() {return id % 97;}
 
-        // TODO:
+    @Override
-        // Return custom hash
+    public boolean equals(Object obj)
+    {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
 
-        // Example:
+        Student other = (Student) obj;
-        // return id % 97;
 
-        return 0;
+        return this.id == other.id;
     }
 
     @Override
-    public boolean equals(Object obj) {
+    public String toString()
-
+    {
-        // TODO:
-
-        // Step 1:
-        // Check null
-
-        // Step 2:
-        // Convert obj to Student
-
-        // Step 3:
-        // Compare IDs
-
-        return false;
-    }
-
-    @Override
-    public String toString() {
-
         return "Student{" +
                 "id=" + id +
                 ", name='" + name + '\'' +
@@ -77,5 +59,4 @@ public class Student {
                 ", gpa=" + gpa +
                 '}';
     }
-
 }

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

@@ -1,55 +1,53 @@
 package dev.service;
 
 import dev.model.Student;
-
 import java.util.ArrayList;
 
-
+public class StudentManager
-public class StudentManager {
+{
-
     private final ArrayList<Student> students = new ArrayList<>();
 
-    public void addStudents(ArrayList<Student> newStudents) {
+    public void addStudents(ArrayList<Student> newStudents)
-
+    {
-        // TODO:
+        students.addAll(newStudents);
-
-        // Merge students
-
-        // Hint:
-        // addAll()
-
     }
 
-    public Student searchStudent(int id) {
+    public Student searchStudent(int id)
-
+    {
-        // TODO:
+        for (Student student : students)
-
+        {
-        // Loop through students
+            if (student.getId() == id) {return student;}
-
+        }
-        // Compare IDs
-
         return null;
     }
 
-    public boolean removeStudent(int id) {
+    public boolean removeStudent(int id)
+    {
+        Student foundStudent = null;
 
-        // TODO:
+        for (Student student : students)
+        {
+            if (student.getId() == id)
+            {
+                foundStudent = student;
+                break;
+            }
+        }
 
-        // Find student
+        if (foundStudent != null)
-
+        {
-        // Remove student
+            students.remove(foundStudent);
+            return true;
+        }
 
         return false;
     }
 
-    public void printStudents() {
+    public void printStudents()
-
+    {
-        for (Student student : students) {
+        for (Student student : students)
-
+        {
             System.out.println(student);
-
         }
-
     }
-
 }

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

@@ -1,59 +1,51 @@
 package dev.thread;
 
-
-
 import dev.model.Student;
-
 import java.util.ArrayList;
 import java.util.List;
 
-public class StudentLoader extends Thread {
+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) {
+    public StudentLoader(List<String> lines) {this.lines = lines;}
-
-        this.lines = lines;
-    }
 
     @Override
-    public void run() {
+    public void run()
+    {
+        for (String line : lines)
+        {
+            if (line == null || line.trim().isEmpty()) {continue;}
 
-        // TODO:
+            String[] parts = line.split(",");
 
-        /*
+            if (parts.length == 4)
-        Example line:
+            {
+                try
+                {
+                    int id = Integer.parseInt(parts[0].trim());
+                    String name = parts[1].trim();
+                    String major = parts[2].trim();
+                    double gpa = Double.parseDouble(parts[3].trim());
 
-        1001,Aryan,Computer Science,3.7
+                    Student student = new Student(id, name, major, gpa);
-         */
 
-        for (String line : lines) {
+                    students.add(student);
-
-            // TODO:
-            // split line
-
-            // TODO:
-            // read values
-
-            // TODO:
-            // create Student
-
-            // TODO:
-            // add to students list
 
+                }
+                catch (NumberFormatException e)
+                {
+                    System.err.println("Skipping invalid line (format error): " + line);
+                }
+            }
         }
-
     }
 
     public ArrayList<Student> getStudents() {
-
         return students;
     }
-
 }

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

@@ -2,31 +2,26 @@ 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));
 
         String line;
 
-        while ((line = reader.readLine()) != null) {
+        while ((line = reader.readLine()) != null)
-
+        {
-            // TODO:
+            if (!line.trim().isEmpty()) {lines.add(line);}
-
-            // Add line to list
-
         }
 
         reader.close();
 
         return lines;
     }
-
 }