工厂方法枚举

package com.example.demo;

public enum Factory {
    CIRCLE(new Circle(),"CIRCLE"),
    RECTANGLE(new Rectangle(),"RECTANGLE"),
    SQUARE(new Square(),"SQUARE");

    // 成员变量
    private Shape shape;
    private String name;



    // 普通方法
    public static Shape getShape(String name) {
        for (Factory c : Factory.values()) {
            if (c.name == name) {
                return c.shape;
            }
        }
        return null;
    }
    // 构造方法
    private Factory(Shape shape, String name) {
        this.shape = shape;
        this.name = name;
    }


}

class   FactoryPatternDemo{
    public static void main(String[] args) {
        Factory.getShape("CIRCLE").draw();
        Factory.getShape("RECTANGLE").draw();
        Factory.getShape("SQUARE").draw();
    }
}

Inside Circle::draw() method.
Inside Rectangle::draw() method.
Inside Square::draw() method.