OOP: Composite Pattern

Design Patterns - Composite Pattern

Composite pattern is used where we need to treat a group of objects in similar
way as a single object. Composite pattern composes objects in term of a tree structure
to represent part as well as whole hierarchy. This type of design pattern comes
under structural pattern as this pattern creates a tree structure of group of objects.

Key Idea.

This pattern creates a class that contains group of its own objects. This class provides     
ways to modify its group of same objects.

Example:

public class Employee {

	private String name;
	private String department;
	private double salary;
	private List<Employee> subordinates;
        
        public Employee(String name, String department, double salary) {
		this.name = name;
		this.department = department;
		this.salary = salary;
		this.subordinates = new ArrayList<Employee>();
	}
}