class1.cs

来自DoFactory的设计模式, 由于是本人根据已有代码创建,没有NETOptimized项

// Composite pattern -- Structural example  

using System;
using System.Collections;

namespace DoFactory.GangOfFour.Composite.Structural
{

    // MainApp test application 

    class MainApp
    {
        static void Main()
        {
            // Create a tree structure 
            Composite root = new Composite("root");
            root.Add(new Leaf("Leaf A"));
            root.Add(new Leaf("Leaf B"));

            Composite comp = new Composite("Composite X");
            comp.Add(new Leaf("Leaf XA"));
            comp.Add(new Leaf("Leaf XB"));

            root.Add(comp);
            root.Add(new Leaf("Leaf C"));

            // Add and remove a leaf 
            Leaf leaf = new Leaf("Leaf D");
            root.Add(leaf);
            root.Remove(leaf);

            // Recursively display tree 
            root.Display(1);

            // Wait for user 
            Console.Read();
        }
    }

    // "Component" 

    abstract class Component
    {
        protected string name;

        // Constructor 
        public Component(string name)
        {
            this.name = name;
        }

        public abstract void Add(Component c);
        public abstract void Remove(Component c);
        public abstract void Display(int depth);
    }

    // "Composite" 

    class Composite : Component
    {
        private ArrayList children = new ArrayList();

        // Constructor 
        public Composite(string name)
            : base(name)
        {
        }

        public override void Add(Component component)
        {
            children.Add(component);
        }

        public override void Remove(Component component)
        {
            children.Remove(component);
        }

        public override void Display(int depth)
        {
            Console.WriteLine(new String('-', depth) + name);

            // Recursively display child nodes 
            foreach (Component component in children)
            {
                component.Display(depth + 2);
            }
        }
    }

    // "Leaf" 

    class Leaf : Component
    {
        // Constructor 
        public Leaf(string name)
            : base(name)
        {
        }

        public override void Add(Component c)
        {
            Console.WriteLine("Cannot add to a leaf");
        }

        public override void Remove(Component c)
        {
            Console.WriteLine("Cannot remove from a leaf");
        }

        public override void Display(int depth)
        {
            Console.WriteLine(new String('-', depth) + name);
        }
    }
}