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 -- Real World example  

using System;
using System.Collections;

namespace DoFactory.GangOfFour.Composite.RealWorld
{

    // Mainapp test application 

    class MainApp
    {
        static void Main()
        {
            // Create a tree structure 
            CompositeElement root =
              new CompositeElement("Picture");
            root.Add(new PrimitiveElement("Red Line"));
            root.Add(new PrimitiveElement("Blue Circle"));
            root.Add(new PrimitiveElement("Green Box"));

            CompositeElement comp =
              new CompositeElement("Two Circles");
            comp.Add(new PrimitiveElement("Black Circle"));
            comp.Add(new PrimitiveElement("White Circle"));
            root.Add(comp);

            // Add and remove a PrimitiveElement 
            PrimitiveElement pe =
              new PrimitiveElement("Yellow Line");
            root.Add(pe);
            root.Remove(pe);

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

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

    // "Component" Treenode 

    abstract class DrawingElement
    {
        protected string name;

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

        public abstract void Add(DrawingElement d);
        public abstract void Remove(DrawingElement d);
        public abstract void Display(int indent);
    }

    // "Leaf" 

    class PrimitiveElement : DrawingElement
    {
        // Constructor 
        public PrimitiveElement(string name)
            : base(name)
        {
        }

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

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

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

    // "Composite" 

    class CompositeElement : DrawingElement
    {
        private ArrayList elements = new ArrayList();

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

        public override void Add(DrawingElement d)
        {
            elements.Add(d);
        }

        public override void Remove(DrawingElement d)
        {
            elements.Remove(d);
        }

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

            // Display each child element on this node 
            foreach (DrawingElement c in elements)
            {
                c.Display(indent + 2);
            }
        }
    }
}