四．享元模式实例分析（Example）

1、场景

2、代码

1、字符工厂类CharacterFactory

class CharacterFactory {     private Dictionary<char, Character> _characters = new Dictionary<char, Character>();     public Character GetCharacter(char key)     {         // Uses "lazy initialization"         Character character = null;         if (_characters.ContainsKey(key))         {             character = _characters[key];         }         else         {             switch (key)             {                 case 'A': character = new CharacterA(); break;                 case 'B': character = new CharacterB(); break;                 //...                 case 'Z': character = new CharacterZ(); break;             }             _characters.Add(key, character);         }         return character;     } }

2、抽象数据对象类DataObject及其具体实现类CustomersData

/// <summary> /// The 'Flyweight' abstract class /// </summary> abstract class Character {     protected char symbol;     protected int width;     protected int height;     protected int ascent;     protected int descent;     protected int pointSize;     public abstract void Display(int pointSize); } /// <summary> /// A 'ConcreteFlyweight' class /// </summary> class CharacterA : Character {     public CharacterA()     {         this.symbol = 'A';         this.height = 100;         this.width = 120;         this.ascent = 70;         this.descent = 0;     }     public override void Display(int pointSize)     {         this.pointSize = pointSize;         Console.WriteLine(this.symbol + " (pointsize " + this.pointSize + ")");     } } /// <summary> /// A 'ConcreteFlyweight' class /// </summary> class CharacterB : Character {     public CharacterB()     {         this.symbol = 'B';         this.height = 100;         this.width = 140;         this.ascent = 72;         this.descent = 0;     }     public override void Display(int pointSize)     {         this.pointSize = pointSize;         Console.WriteLine(this.symbol + " (pointsize " + this.pointSize + ")");     } } // ... C, D, E, etc. /// <summary> /// A 'ConcreteFlyweight' class /// </summary> class CharacterZ : Character {     // Constructor     public CharacterZ()     {         this.symbol = 'Z';         this.height = 100;         this.width = 100;         this.ascent = 68;         this.descent = 0;     }     public override void Display(int pointSize)     {         this.pointSize = pointSize;         Console.WriteLine(this.symbol +" (pointsize " + this.pointSize + ")");     } }

3、客户端代码

static void Main(string[] args) {     // Build a document with text     string document = "AAZZBBZB";     char[] chars = document.ToCharArray();     CharacterFactory factory = new CharacterFactory();     // extrinsic state     int pointSize = 10;     // For each character use a flyweight object     foreach (char c in chars)     {         pointSize++;         Character character = factory.GetCharacter(c);         character.Display(pointSize);     }     Console.ReadKey(); }

3、实例运行结果

五、总结（Summary）

本文转自 灵动生活 51CTO博客，原文链接：http://blog.51cto.com/smartlife/269010，如需转载请自行联系原作者