设计形式学习之享元模式

设计模式学习之享元模式

享元模式：运用共享技术有效地支持大量细粒度的对象。主要用于避免大量非常相似类的开销。在很多程序设计中，有时需要生成大量细粒度的类实例来表示数据，这时候可以采用享元模式来共享这些类实例，从而减少这些实例的数量。

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代码示例：

享元抽象类：package DesignPattern.FlyweightPattern;public abstract class Flyweight {public abstract void Operate(int i);}

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具体享元类：package DesignPattern.FlyweightPattern;public class ConcreateFlyweight extends Flyweight {@Overridepublic void Operate(int i) {// TODO Auto-generated method stubSystem.out.println("具体享元：" + i);}}

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享元抽象类：package DesignPattern.FlyweightPattern;import java.util.Hashtable;public class FlyweightFactory {private Hashtable flyWeights = new Hashtable();public FlyweightFactory() {this.flyWeights.put("A", new ConcreateFlyweight());this.flyWeights.put("B", new ConcreateFlyweight());this.flyWeights.put("C", new ConcreateFlyweight());}public Flyweight getFlyweight(String key) {return (Flyweight) flyWeights.get(key);}}

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主控程序类：package DesignPattern.FlyweightPattern;public class Client {public static void main(String[] args) {int i = 1;FlyweightFactory factory = new FlyweightFactory();Flyweight fly1 = factory.getFlyweight("A");fly1.Operate(++i);Flyweight fly2 = factory.getFlyweight("B");fly2.Operate(++i);Flyweight fly3 = factory.getFlyweight("C");fly3.Operate(++i);Flyweight fly4 = factory.getFlyweight("B");fly4.Operate(++i);Flyweight fly5 = factory.getFlyweight("B");fly5.Operate(++i);Flyweight fly6 = factory.getFlyweight("B");fly6.Operate(++i);}}

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