享元模式(Flyweight):运用共享技术有效地支持大量细粒度的对象。
Flyweight:所有具体享元类的超类或接口，通过这个接口，Flyweight可以接受并作用于外部状态
ConcreteFlyweight:继承Flyweight超类或实现Flyweight接口，并为内部状态增加存储空间。
UnsharedConcreteFlyweight:不需要共享的Flyweight子类。因为Flyweight接口共享成为可能，但不强制共享.
FlyweightFactory:享元工厂，用来创建并管理Flyweight对象。主要用来确保合理并共享Flyweight当用户请求一个Flyweight时，FlyweightFactory对象提供一个已创建的实例或者创建一个。
使用范围：1.如果一个应用程序使用了大量的对象，而大量的这些对象造成了很大的存储开销
2.对象的大多数状态可以外部状态，如果删除对象的外部状态，那么可以用相对较少的共享对象取代
Flyweight1.cs
代码
using System;
using System.Data;
using System.Configuration;
using System.Collections;
// 享元模式(Flyweight):运用共享技术有效地支持大量细粒度的对象。
// Flyweight:所有具体享元类的超类或接口，通过这个接口，Flyweight可以接受并作用于外部状态
// ConcreteFlyweight:继承Flyweight超类或实现Flyweight接口，并为内部状态增加存储空间。
// UnsharedConcreteFlyweight:不需要共享的Flyweight子类。因为Flyweight接口共享成为可能，但不
// 强制共享.
// FlyweightFactory:享元工厂，用来创建并管理Flyweight对象。主要用来确保合理并共享Flyweight
// 当用户请求一个Flyweight时，FlyweightFactory对象提供一个已创建的实例或者创建一个。
// 使用范围：1.如果一个应用程序使用了大量的对象，而大量的这些对象造成了很大的存储开销
// 2.对象的大多数状态可以外部状态，如果删除对象的外部状态，那么可以用相对较少的共享对象取代
namespace Flyweight
{
class Flyweight1
{
}
// Flyweight
abstract class Flyweight
{
public abstract void Operation( int extrinsicstate);
}
// ConcreteFlyweight
class ConcreteFlyweight : Flyweight
{
public override void Operation( int extrinsicstate)
{
Console.WriteLine( " 具体Flyweight " + extrinsicstate);
}
}
// UnshareConcreteFlyweight
class UnshareConcreteFlyweight : Flyweight
{
public override void Operation( int extrinsicstate)
{
Console.WriteLine( " 不共享的具体Flyweight: " + extrinsicstate);
}
}
// FlyweightFactory
class FlyweightFactory
{
private Hashtable flyweights = new Hashtable();
public FlyweightFactory()
{
flyweights.Add( " X " , new ConcreteFlyweight());
flyweights.Add( " Y " , new ConcreteFlyweight());
flyweights.Add( " Z " , new ConcreteFlyweight());
}
public Flyweight GetFlyweight( string key)
{
return ((Flyweight)flyweights[key]);
}
}
}
Program.cs
代码
using System;
using System.Collections.Generic;
using System.Text;
namespace Flyweight
{
class Program
{
static void Main( string [] args)
{
int extrinsicstate = 22 ;
FlyweightFactory f = new FlyweightFactory();
Flyweight fx = f.GetFlyweight( " X " );
fx.Operation( -- extrinsicstate);
Flyweight fy = f.GetFlyweight( " Y " );
fx.Operation( -- extrinsicstate);
Flyweight fz = f.GetFlyweight( " Z " );
fz.Operation( -- extrinsicstate);
Flyweight ur = new UnshareConcreteFlyweight();
ur.Operation( -- extrinsicstate);
Console.Read();
}
}
}
运行结果：
具体Flyweight21
具体Flyweight20
具体Flyweight19
不共享的具体Flyweight:18