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

// Flyweight pattern -- Real World example  

using System;
using System.Collections;

namespace DoFactory.GangOfFour.Flyweight.RealWorld
{

    // MainApp test application 

    class MainApp
    {
        static void Main()
        {
            // Build a document with text 
            string document = "AAZZBBZB";
            char[] chars = document.ToCharArray();

            CharacterFactory f = new CharacterFactory();

            // extrinsic state 
            int pointSize = 10;

            // For each character use a flyweight object 
            foreach (char c in chars)
            {
                pointSize++;
                Character character = f.GetCharacter(c);
                character.Display(pointSize);
            }

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

    // "FlyweightFactory" 

    class CharacterFactory
    {
        private Hashtable characters = new Hashtable();

        public Character GetCharacter(char key)
        {
            // Uses "lazy initialization" 
            Character character = characters[key] as Character;
            if (character == null)
            {
                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;
        }
    }

    // "Flyweight" 

    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);
    }

    // "ConcreteFlyweight" 

    class CharacterA : Character
    {
        // Constructor 
        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 + ")");
        }
    }

    // "ConcreteFlyweight" 

    class CharacterB : Character
    {
        // Constructor 
        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. 

    // "ConcreteFlyweight" 

    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 + ")");
        }
    }
}