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

package com.demo.flyweight;

//享元接口
public interface Flyweight {
	public double getHeight();
	public double getWidth();
	public double getLength();
	//使用参数mess获取外部数据
	public void printMess(String Mess);
}

package com.demo.flyweight;

import java.util.HashMap;

//享元工厂
public class FlyweightFactory {

	private HashMap<String, Flyweight> hashMap;
	static FlyweightFactory factory = new FlyweightFactory();

	private FlyweightFactory() {
		hashMap = new HashMap<String, Flyweight>();
	}

	public static FlyweightFactory getFactory() {
		return factory;
	}

	public synchronized Flyweight getFlyweight(String key) {
		if (hashMap.containsKey(key)) {
			return hashMap.get(key);
		} else {
			double width = 0, height = 0, length = 0;
			String[] str = key.split("#");
			width = Double.parseDouble(str[0]);
			height = Double.parseDouble(str[1]);
			length = Double.parseDouble(str[2]);
			Flyweight ft = new ConcreteFlyweight(width, height, length);
			hashMap.put(key, ft);
			return ft;
		}
	}
	
	//ConcreteFlyweight是内部类
	class ConcreteFlyweight implements Flyweight {

		private double width;
		private double height;
		private double length;

		private ConcreteFlyweight(double width, double height, double length) {
			this.width = width;
			this.height = height;
			this.length = length;
		}

		@Override
		public double getHeight() {
			// TODO Auto-generated method stub
			return height;
		}

		@Override
		public double getWidth() {
			// TODO Auto-generated method stub
			return width;
		}

		@Override
		public double getLength() {
			// TODO Auto-generated method stub
			return length;
		}

		@Override
		public void printMess(String Mess) {
			// TODO Auto-generated method stub
			//输出外部数据mess
			System.out.print(Mess);
			//输出内部数据width
			System.out.print("宽度:" + width);
			System.out.print("高度:" + height);
			System.out.println("长度:" + length);
		}
	}
}

package com.demo.flyweight;


public class Car {

	//存放享元对象的引用
	Flyweight flyweight;
	String name,color;
	int power;
	
	Car(Flyweight flyweight,String name,String color,int power){
		this.flyweight=flyweight;
		this.name=name;
		this.color=color;
		this.power=power;
	}
	
	public void print(){
		System.out.print("名称:"+name);
		System.out.print("颜色:"+color);
		System.out.print("功率:"+power);
		System.out.print("宽度:"+flyweight.getWidth());
		System.out.print("高度:"+flyweight.getHeight());
		System.out.println("长度:"+flyweight.getLength());
	}
}

package com.demo.flyweight;

public class Application {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		FlyweightFactory factory=FlyweightFactory.getFactory();
		double width=1.8,height=1.47,length=5.12;
		String key=""+width+"#"+height+"#"+length;
		Flyweight flyweight=factory.getFlyweight(key);
		Car audiA6One=new Car(flyweight,"奥迪A6","黑色",128);
		Car audiA6Two=new Car(flyweight,"奥迪A6","灰色",160);
		audiA6One.print();
		audiA6Two.print();
		
		width=1.77;
		height=1.45;
		length=4.63;
		key=""+width+"#"+height+"#"+length;
		flyweight=factory.getFlyweight(key);
		Car audiA4One=new Car(flyweight,"奥迪A4","黑色",126);
		Car audiA4Two=new Car(flyweight,"奥迪A4","灰色",138);
		
		flyweight.printMess("名称：奥迪 A4 颜色：蓝色 功率：126");
		flyweight.printMess("名称：奥迪 A6 颜色：红色 功率：138");
	}
}

名称:奥迪A6颜色:黑色功率:128宽度:1.8高度:1.47长度:5.12
名称:奥迪A6颜色:灰色功率:160宽度:1.8高度:1.47长度:5.12
名称：奥迪 A4 颜色：蓝色 功率：126宽度:1.77高度:1.45长度:4.63
名称：奥迪 A6 颜色：红色 功率：138宽度:1.77高度:1.45长度:4.63