Flyweight

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace Flyweight{ class Program { 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); } // Wait for user Console.ReadKey(); } } /// <summary> /// The 'FlyweightFactory' class /// </summary> 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; } } /// <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 { // 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 + ")"); } } /// <summary> /// A 'ConcreteFlyweight' class /// </summary> 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. /// <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 + ")"); } }}