GoF——组合模式

 

组合模式：将对象组合成树形结构以表示“部分-真题”的结构层次。组合模式使得用户对单个对象和组合对象的使用具有一致性。

 

结构图：

 

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Text;
  4 
  5 namespace 组合模式
  6 {
  7     class Program
  8     {
  9         static void Main(string[] args)
 10         {
 11             Composite root = new Composite("root");
 12             root.Add(new Leaf("Leaf A"));
 13             root.Add(new Leaf("Leaf B"));
 14 
 15             Composite comp = new Composite("Composite X");
 16             comp.Add(new Leaf("Leaf XA"));
 17             comp.Add(new Leaf("Leaf XB"));
 18 
 19             root.Add(comp);
 20 
 21             Composite comp2 = new Composite("Composite XY");
 22             comp2.Add(new Leaf("Leaf XYA"));
 23             comp2.Add(new Leaf("Leaf XYB"));
 24 
 25             comp.Add(comp2);
 26 
 27             root.Add(new Leaf("Leaf C"));
 28 
 29             Leaf leaf = new Leaf("Leaf D");
 30             root.Add(leaf);
 31             root.Remove(leaf);
 32 
 33             root.Display(1);
 34 
 35             Console.Read();
 36         }
 37     }
 38 
 39     abstract class Component
 40     {
 41         protected string name;
 42 
 43         public Component(string name)
 44         {
 45             this.name = name;
 46         }
 47 
 48         public abstract void Add(Component c);
 49         public abstract void Remove(Component c);
 50         public abstract void Display(int depth);
 51     }
 52 
 53     class Composite : Component
 54     {
 55         private List<Component> children = new List<Component>();
 56 
 57         public Composite(string name)
 58             : base(name)
 59         { }
 60 
 61         public override void Add(Component c)
 62         {
 63             children.Add(c);
 64         }
 65 
 66         public override void Remove(Component c)
 67         {
 68             children.Remove(c);
 69         }
 70 
 71         public override void Display(int depth)
 72         {
 73             Console.WriteLine(new String('-', depth) + name);
 74 
 75             foreach (Component component in children)
 76             {
 77                 component.Display(depth + 2);
 78             }
 79         }
 80     }
 81 
 82     class Leaf : Component
 83     {
 84         public Leaf(string name)
 85             : base(name)
 86         { }
 87 
 88         public override void Add(Component c)
 89         {
 90             Console.WriteLine("Cannot add to a leaf");
 91         }
 92 
 93         public override void Remove(Component c)
 94         {
 95             Console.WriteLine("Cannot remove from a leaf");
 96         }
 97 
 98         public override void Display(int depth)
 99         {
100             Console.WriteLine(new String('-', depth) + name);
101         }
102     }
103 }
Composite

 

当你发现需求中是体现部分与整体的结构时，以及你希望用户可以忽略组合对象与单个对象的不同，统一地使用组合结构中的多有对象时，就应该考虑用组合模式。

 

posted @ 2016-04-07 15:04  图哈特  阅读(232)  评论(0)  编辑  收藏  举报