Designing a Task Management System

Requirements

1. The task management system should allow users to create, update, and delete tasks.
2. Each task should have a title, description, due date, priority, and status (e.g., pending, in progress, completed).
3. Users should be able to assign tasks to other users and set reminders for tasks.
4. The system should support searching and filtering tasks based on various criteria (e.g., priority, due date, assigned user).
5. Users should be able to mark tasks as completed and view their task history.
6. The system should handle concurrent access to tasks and ensure data consistency.
7. The system should be extensible to accommodate future enhancements and new features.

UML Class Diagram

Implementations

Java Implementation

Python Implementation

C++ Implementation

C# Implementation

Go Implementation

TypeScript Implementation

Classes, Interfaces and Enumerations

1. The User class represents a user in the task management system, with properties such as id, name, and email.
2. The TaskStatus enum defines the possible states of a task, such as pending, in progress, and completed.
3. The Task class represents a task in the system, with properties like id, title, description, due date, priority, status, and assigned user.
4. The TaskManager class is the core of the task management system and follows the Singleton pattern to ensure a single instance of the task manager.
5. The TaskManager class uses concurrent data structures (ConcurrentHashMap and CopyOnWriteArrayList) to handle concurrent access to tasks and ensure thread safety.
6. The TaskManager class provides methods for creating, updating, deleting, searching, and filtering tasks, as well as marking tasks as completed and retrieving task history for a user.
7. The TaskManagementSystem class serves as the entry point of the application and demonstrates the usage of the task management system.