C#設計模式之享元設計模式（Flyweight）(2)

三、單純享元模式的示意性源代碼

// Flyweight pattern -- Structural example　
using System;
using System.Collections;
// "FlyweightFactory"
class FlyweightFactory
{
　// FIElds
　private Hashtable flyweights = new Hashtable();
　// Constructors
　public FlyweightFactory()
　{
　　flyweights.Add("X", new ConcreteFlyweight());
　　flyweights.Add("Y", new ConcreteFlyweight());
　　flyweights.Add("Z", new ConcreteFlyweight());
　}
　// Methods
　public Flyweight GetFlyweight(string key)
　{
　　return((Flyweight)flyweights[ key ]);
　}
}
// "Flyweight"
abstract class Flyweight
{
　// Methods
　abstract public void Operation( int extrinsicstate );
}
// "ConcreteFlyweight"
class ConcreteFlyweight : Flyweight
{
　private string intrinsicstate = "A";
　// Methods
　override public void Operation( int extrinsicstate )
　{
　　Console.WriteLine("ConcreteFlyweight: intrinsicstate {0}, extrinsicstate {1}",
　　　intrinsicstate, extrinsicstate );
　}
}
/**//// <summary>
/// ClIEnt test
/// </summary>
public class ClIEnt
{
　public static void Main( string[] args )
　{
　　// Arbitrary extrisic state
　　int extrinsicstate = 22;
　　FlyweightFactory f = new FlyweightFactory();
　　// Work with different flyweight instances
　　Flyweight fx = f.GetFlyweight("X");
　　fx.Operation( --extrinsicstate );
　　Flyweight fy = f.GetFlyweight("Y");
　　fy.Operation( --extrinsicstate );
　　Flyweight fz = f.GetFlyweight("Z");
　　fz.Operation( --extrinsicstate );
　}
}