task-management-system.md

Designing a Task Management System

In this article, we explore the design and implementation of a Task Management System using Java, with a focus on object-oriented principles.

The system allows users to create, manage, and track tasks effectively.

System Requirements

The Task Management System should:

1. Task Creation and Management: Enable users to create, update, and delete tasks.
2. User Management: Manage user accounts and associated tasks.
3. Task Assignment: Allow tasks to be assigned to specific users.
4. Task Tracking: Track the progress and status of tasks.
5. Notifications: Notify users about task deadlines and updates.

Core Use Cases

1. Managing User Accounts
2. Creating and Updating Tasks
3. Assigning Tasks to Users
4. Tracking Task Progress
5. Sending Notifications

Key Classes:

• TaskManagementSystem: Manages the overall system.
• User: Represents a system user.
• Task: Represents a task.
• TaskStatus: Enum for task status.

Java Implementation

User Class

Manages user account information.

import java.util.ArrayList;
import java.util.List;

public class User {
    private String userId;
    private String name;
    private List<Task> assignedTasks;

    public User(String userId, String name) {
        this.userId = userId;
        this.name = name;
        this.assignedTasks = new ArrayList<>();
    }

    public void addTask(Task task) {
        assignedTasks.add(task);
    }

    // Getters and setters...
}

Task Class

Represents a task.

import java.util.Date;

public class Task {
    private String taskId;
    private String title;
    private String description;
    private Date dueDate;
    private TaskStatus status;

    public Task(String taskId, String title, Date dueDate) {
        this.taskId = taskId;
        this.title = title;
        this.dueDate = dueDate;
        this.status = TaskStatus.PENDING;
    }

    public void updateStatus(TaskStatus newStatus) {
        this.status = newStatus;
    }

    // Getters and setters...
}

enum TaskStatus {
    PENDING, IN_PROGRESS, COMPLETED, CANCELLED
}

TaskManagementSystem Class

Manages task management operations.

import java.util.ArrayList;
import java.util.List;

public class TaskManagementSystem {
    private List<User> users;
    private List<Task> tasks;

    public TaskManagementSystem() {
        this.users = new ArrayList<>();
        this.tasks = new ArrayList<>();
    }

    public void addUser(User user) {
        users.add(user);
    }

    public void addTask(Task task) {
        tasks.add(task);
    }

    public void assignTaskToUser(String taskId, String userId) {
        User user = findUserById(userId);
        Task task = findTaskById(taskId);

        if (user != null && task != null) {
            user.addTask(task);
        }
    }

    public User findUserById(String userId) {
        for (User user : users) {
            if (user.getUserId().equals(userId)) {
                return user;
            }
        }
        return null;
    }

    public Task findTaskById(String taskId) {
        for (Task task : tasks) {
            if (task.getTaskId().equals(taskId)) {
                return task;
            }
        }
        return null;
    }