learning之享元模式

享元模式：享元模式以共享的方式高效地支持大量细粒度对象的重用，就是对象复用，以节省内存和创建消耗。

Flyweight：享元对象抽象基类或者接口；
ConcreteFlyweight：具体的共享的享元对象；
UnsharedConcreteFlyweight：非共享部分；

FlyweightFactory：工厂方法管理享元对象池和创建享元对象。

图片来自网络：

实例：

//抽象基类或接口public interface Car {    public void run();}

//具体的对象public class ConcreatCar implements Car{    private String carInfo;    public ConcreatCar(String state){        carInfo=state;    }    @Override    public void run() {        System.out.print("car state :"+carInfo);    }}

//享元对象工厂方法public class CarFactory {    HashMap<String,Car> cars=new HashMap<>();    public Car getCar(String key){        if(cars.get(key)==null){            ConcreatCar concreatCar=new ConcreatCar(key);            cars.put(key,concreatCar);            return concreatCar;        }else {            return cars.get(key);        }    }    public int size(){        return cars.size();    }}

public class Test {    public static void main(String[] args){        CarFactory carFactory=new CarFactory();        Car concreatCar1=carFactory.getCar("yellow");        Car concreatCar2=carFactory.getCar("blue");        Car concreatCar3=carFactory.getCar("yellow");        Car concreatCar4=carFactory.getCar("yellow");        System.out.print("Cars pool size: "+carFactory.size());//size=2    }}