享元
Terrylee,2006年3月
摘要:面向对象的思想很好地解决了抽象性的问题,一般也不会出现性能上的问题。但是在某些情况下,对象的数量可能会太多,从而导致了运行时的代价。那么我们如何去避免大量细粒度的对象,同时又不影响客户程序使用面向对象的方式进行操作?
本文试图通过一个简单的字符处理的例子,运用重构的手段,一步步带你走进Flyweight模式,在这个过程中我们一同思考、探索、权衡,通过比较而得出好的实现方式,而不是给你最终的一个完美解决方案。
主要内容:
1. Flyweight模式解说
2..NET中的Flyweight模式
3.Flyweight模式的实现要点
……
概述
面向对象的思想很好地解决了抽象性的问题,一般也不会出现性能上的问题。但是在某些情况下,对象的数量可能会太多,从而导致了运行时的代价。那么我们如何去避免大量细粒度的对象,同时又不影响客户程序使用面向对象的方式进行操作?
意图
运用共享技术有效地支持大量细粒度的对象。[GOF 《设计模式》]
结构图
代码
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namespace Bll
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{
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public class Car
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{
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public string Body;
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public string Wheel;
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public string Engine;
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public string Color;
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public Car(string body, string wheel, string engine, string color)
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{
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}
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}
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public class FlyWeightCar
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{
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public String Brand;
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private Car car;
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public Car Car
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{
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get { return car; }
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set { car = value; }
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}
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}
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public class FlyWeightFactory
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{
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private static FlyWeightCar car;
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private static Hashtable table = new Hashtable();
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public static FlyWeightCar CreateInit(string body, string wheel, string engine, string brand, string color)
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{
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if (table[brand] != null)
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{
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car = (FlyWeightCar)table[brand];
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}
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else
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{
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car = new FlyWeightCar();
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car.Brand = brand;
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car.Car = new Car(body, wheel, engine, color);
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table.Add(brand, car);
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}
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return car;
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}
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}
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}
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