设计模式-结构型-享元模式Flyweight

享元模式的特点：

        享元模式可以共享相同的对象，避免创建过多的对象实例，从而节省内存资源

使用场景：

        常用于需要创建大量相似的对象的情况

编辑

享元接口类

public interface Flyweight { void operate(String extrinsicState); }

享元实现类

public class ConcreteFlyweight implements Flyweight {
    @Override
    public void operate(String extrinsicState) {
        System.out.println("固有状态： " + intrinsicState);
        System.out.println("外部状态 " + extrinsicState);
    }
}

享元工厂类

public class FlyweightFactory {
    private Map<String, Flyweight> flyweights;

    public Flyweight getFlyweight(String intrinsicState) {
        if (flyweights.containsKey(intrinsicState)) {
            return flyweights.get(intrinsicState);
        } else {
            Flyweight flyweight = new ConcreteFlyweight(intrinsicState);
            flyweights.put(intrinsicState, flyweight);
            return flyweight;
        }
    }
}

演示类

public class Demo {
    public static void main(String[] args) {
        FlyweightFactory factory = new FlyweightFactory();

        //保存固有状态
        Flyweight flyweight1 = factory.getFlyweight("SharedState");
        Flyweight flyweight2 = factory.getFlyweight("SharedState");

        //处理外部状态
        flyweight1.operate("ExtrinsicState1");
        flyweight2.operate("ExtrinsicState2");
    }
}

演示结果

为了使演示代码更简洁，我移除了构造方法和set/get方法