ADD: Java Generics - Creating a Generic To-Do List Manager

Author: Nipuna-Lakruwan

Beginner/Project1_ToDoList/Lesson6/src/Main.java

@@ -0,0 +1,54 @@
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        TodoListManager<String> toDoListManager = new TodoListManager<>();  // Managing String tasks
+        String command;
+
+        do {
+            System.out.println("\nEnter a command (add/view/remove/complete/save/load/exit):");
+            command = scanner.nextLine();
+
+            switch (command) {
+                case "add":
+                    System.out.println("Enter the task:");
+                    String task = scanner.nextLine();
+                    toDoListManager.addTask(task);
+                    break;
+                case "view":
+                    toDoListManager.viewTasks();
+                    break;
+                case "remove":
+                    System.out.println("Enter the task number to remove:");
+                    int taskNumber = scanner.nextInt();
+                    scanner.nextLine(); // Consume newline
+                    toDoListManager.removeTask(taskNumber);
+                    break;
+                case "complete":
+                    System.out.println("Enter the task number to complete:");
+                    int completeTaskNumber = scanner.nextInt();
+                    scanner.nextLine(); // Consume newline
+                    toDoListManager.completeTask(completeTaskNumber);
+                    break;
+                case "save":
+                    System.out.println("Enter the filename to save tasks:");
+                    String saveFilename = scanner.nextLine();
+                    toDoListManager.saveTasksToFile(saveFilename);
+                    break;
+                case "load":
+                    System.out.println("Enter the filename to load tasks:");
+                    String loadFilename = scanner.nextLine();
+                    toDoListManager.loadTasksFromFile(loadFilename);
+                    break;
+                case "exit":
+                    System.out.println("Exiting the application.");
+                    break;
+                default:
+                    System.out.println("Invalid command.");
+            }
+        } while (!command.equals("exit"));
+
+        scanner.close();
+    }
+}

Beginner/Project1_ToDoList/Lesson6/src/TodoList.java

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+import java.util.ArrayList;
+import java.io.*;
+
+public class TodoListManager<T> {
+    private ArrayList<T> tasks;
+
+    public TodoListManager() {
+        tasks = new ArrayList<>();
+    }
+
+    public void addTask(T task) {
+        tasks.add(task);
+        System.out.println("Task added: " + task);
+    }
+
+    public void viewTasks() {
+        if (tasks.isEmpty()) {
+            System.out.println("No tasks in the list.");
+        } else {
+            for (int i = 0; i < tasks.size(); i++) {
+                System.out.println((i + 1) + ". " + tasks.get(i));
+            }
+        }
+    }
+
+    public void removeTask(int index) {
+        if (index >= 1 && index <= tasks.size()) {
+            System.out.println("Task removed: " + tasks.get(index - 1));
+            tasks.remove(index - 1);
+        } else {
+            System.out.println("Invalid task number.");
+        }
+    }
+
+    public void completeTask(int index) {
+        if (index >= 1 && index <= tasks.size()) {
+            System.out.println("Task completed: " + tasks.get(index - 1));
+            tasks.remove(index - 1);
+        } else {
+            System.out.println("Invalid task number.");
+        }
+    }
+
+    public void saveTasksToFile(String filename) {
+        try (FileWriter writer = new FileWriter(filename)) {
+            for (T task : tasks) {
+                writer.write(task.toString() + "\n");
+            }
+            System.out.println("Tasks saved to " + filename);
+        } catch (IOException e) {
+            System.out.println("Error saving tasks: " + e.getMessage());
+        }
+    }
+
+    public void loadTasksFromFile(String filename) {
+        try (BufferedReader reader = new BufferedReader(new FileReader(filename))) {
+            String task;
+            while ((task = reader.readLine()) != null) {
+                // This will need casting depending on the task type
+                System.out.println("Task loaded: " + task);
+            }
+        } catch (IOException e) {
+            System.out.println("Error loading tasks: " + e.getMessage());
+        }
+    }
+}