GoF——组合模式

using System;
using System.Collections.Generic;
using System.Text;

namespace 组合模式
{
class Program
{
static void Main(string[] args)
{
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);

Composite comp2 = new Composite("Composite XY");
comp2.Add(new Leaf("Leaf XYA"));
comp2.Add(new Leaf("Leaf XYB"));

comp.Add(comp2);

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

Leaf leaf = new Leaf("Leaf D");
root.Add(leaf);
root.Remove(leaf);

root.Display(1);

Console.Read();
}
}

abstract class Component
{
protected string name;

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);
}

class Composite : Component
{
private List<Component> children = new List<Component>();

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

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

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

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

foreach (Component component in children)
{
component.Display(depth + 2);
}
}
}

class Leaf : Component
{
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);
}
}
}