Entity component system (ECS) pattern

Description:
The Entity Component System (ECS) design pattern is a robust architectural pattern used in game development and other performance-critical applications. This pattern provides a flexible and efficient way to manage entities and their behaviors by breaking them down into distinct components. The main elements of the ECS pattern include:

1. Entity: A general-purpose object that serves as a container for components. Entities are usually identified by a unique ID and do not contain any logic.
2. Component: A modular, reusable piece of data that describes a specific aspect of an entity, such as position, velocity, or health. Components are passive data holders.
3. System: Logic that operates on entities with specific components. Systems query entities that possess the necessary components and execute game logic, updating component data as needed.

Implementing the ECS pattern involves defining entities, components, and systems, and establishing a way to manage and process these elements efficiently.

References:

• Entity Component System - Wikipedia
• Java Design Patterns - Contribution Guidelines
• Entity Component System Is the Coolest Thing I Ever Met

Acceptance Criteria:

1. Create an Entity class that uniquely identifies each entity.
2. Develop a variety of Component classes that can be associated with entities, such as PositionComponent, VelocityComponent, and HealthComponent.
3. Implement System classes that operate on entities with specific components, including methods for querying relevant entities and updating their components.
4. Provide unit tests that validate the correct behavior of entities, components, and systems.
5. Ensure the implementation adheres to the project's coding standards and contribution guidelines.

Start with the referenced Java Design Patterns contribution guidelines and review how existing patterns in this repository are organized. Define the Entity, Component, and System scope from the acceptance criteria, then add unit tests covering their association, querying, and updates; the work is done when the implementation meets all five criteria and follows the project standards.