Composite Design Pattern

Composite design pattern is a structural pattern that allows you to compose objects into tree-like structures to represent part-whole hierarchies.

Composite design pattern is like organizing things in folders on your computer. Just as a folder can contain files or other folders. This allows you to treat individual objects and groups of objects in a unified way. So, whether you’re working with a single object or a whole collection, you can use the same operations and methods to interact with them.

5 real world example of Composite design pattern

File System: Folders in a file system can contain files or other folders, demonstrating the Composite pattern’s hierarchy.

Menu in Software Applications: Software applications often have menus with submenus, allowing users to navigate through various options and functionalities in a structured manner.

Educational Courses: Online learning platforms organize educational courses hierarchically, with each course containing modules, lessons, quizzes, and assignments.

Organization Chart: An organization chart can represent a hierarchical structure of employees and departments, mirroring the Composite pattern.

Playlist Management: A music player application can organize playlists hierarchically, with each playlist containing individual songs or sub-playlists.

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~:Sample code for Organizational structure using Composite Design Pattern:~

// Component interface
interface Employee {
    void showDetails();
}

// Leaf class representing individual employees
class Developer implements Employee {
    private String name;
    private String position;

    public Developer(String name, String position) {
        this.name = name;
        this.position = position;
    }

    @Override
    public void showDetails() {
        System.out.println("Developer: " + name + ", Position: " + position);
    }
}

// Composite class representing Manager or teams
class Manager implements Employee {
    private String name;
    private List<Employee> subordinates = new ArrayList<>();

    public Manager(String name) {
        this.name = name;
    }

    public void addSubordinate(Employee employee) {
        subordinates.add(employee);
    }

    @Override
    public void showDetails() {
        System.out.println("Manager: " + name);
        System.out.println("Subordinates:");
        for (Employee employee : subordinates) {
            employee.showDetails();
        }
    }
}

public class Main {
    public static void main(String[] args) {
        // Create leaf employees
        Employee developer1 = new Developer("Alice", "Senior Developer");
        Employee developer2 = new Developer("Bob", "Junior Developer");
        Employee developer3 = new Developer("Charlie", "Senior Developer");

        // Create composite managers
        Manager engineeringManager = new Manager("Engineering Manager");
        Manager projectManager = new Manager("Project Manager");

        // Add employees to managers
        engineeringManager.addSubordinate(developer1);
        engineeringManager.addSubordinate(developer2);
        projectManager.addSubordinate(developer3);

        // Add project manager to engineering manager
        engineeringManager.addSubordinate(projectManager);

        // Show details of engineering manager (including subordinates)
        engineeringManager.showDetails();
    }
}