Composite Pattern Simplified
c#, composite
Solution
You're giving up any chance to subclass the "Leaf", if it turns out you have different types of "nodes" you'll probably end up polluting the structure in one way or another. And you're violating the single responsipbility priciple too. It is very easy to get pollution of all sorts with the composite pattern, and I think it always pays off to do it cleanly.
Problem
What do I lose by not implementing the Component and treating everything as a Composite? I have given up the implementation for Leaf node: I.e. ``` class Component : IComponent { /*...*/ } ``` Now plz take a look at my code. ``` public interface IComponent { int ID { get;set; } string Name { get;set;} void Add(IComponent item); void Remove(IComponent item); List<IComponent> Items { get; } void Show(); } public class Composite : IComponent { private int _id; public int ID { get { return _id; } set { _id = value; } } private string _name; public string Name { get { return _name; } set { _name = value; } } public Composite(int id, string name) { _id = id; _name = name; } private List<IComponent> _items = new List<IComponent>(); public void Add(IComponent item) { _items.Add(item); } public void Remove(IComponent item) { _items.Remove(item); } public List<IComponent> Items { get { return new List<IComponent>(_items); } } public void Show() { Console.WriteLine("ID=" + _id + "; Name=" + _name); } } class Program { static void Main(string[] args) { IComponent root = new Composite(1, "World"); IComponent asia = new Composite(2, "Asia"); IComponent europe = new Composite(3, "Europe"); root.Add(asia); root.Add(europe); asia.Add(new Composite(4, "China")); asia.Add(new Composite(5, "Japan")); europe.Add(new Composite(6, "Germany")); europe.Add(new Composite(7, "Russia")); root.Show(); Program.Traverse(root.Items); Console.ReadLine(); } static void Traverse(List<IComponent> items) { foreach (IComponent c in items) { c.Show(); Traverse(c.Items); } } } ``` What is wrong with this approach of Composite Pattern? What kind of problem can I face with this type of design?