下面是一个有关几何图形类的程序，请补充完整___________________________________________；（1）public class Geometric { private String color; private boolean filled; private Date date; public Geometric() { date = new Date(); } public Geometric(String color, boolean filled) { this.color = color; this.filled = filled; _________________________; （2） //获取系统时间 } public void setColor(String color) { this.color = color; } public String getColor() { return color; } public void setFilled(boolean filled) { this.filled = filled; } _____________________________{ （3） //获取是否填充的方法 return filled; } public Date getDate() { return date; } public String toString() { return "颜色：" + color + "，是否填充：" + filled + "，创建时间：" + date ; } public double getArea() { return 0; }}//圆类继承图形类public class Circle ________________ （4）{ private double radius; public Circle() {} public Circle(double radius, String color, boolean filled) { _______________________________; （5） this.radius = radius; } public double getRadius() { return radius; } public void setRadius(double radius) { this.radius = radius; } public double getArea() { return radius*radius*Math.PI; } public double getPerimeter() { return 2*radius*Math.PI; } public double getDiameter() { return 2*radius; } @_______________________（6）//判断是否是方法的重写 public String toString() { return "圆形：【半径为：" + radius + "，颜色为：" + getColor() + "，是否填充" + isFilled() + "，创建时间：" + getDate(); } }//长方形类继承图形类public class Rectangle ____________________ { （7） private double length; private double width; public Rectangle() { _________________________; （8）//调用父类构造方法 } public Rectangle(String color, boolean filled, double length, double width) { super(color,filled); this.length = length; this.width = width; } public double getLength() { return length; } public void setLength(double length) { this.length = length; } public double getWidth() { return width; } public void setWidth(double width) { this.width = width; } public double getArea() { ___________________________; （9） } public double getPerimeter() { return 2*（length+width）; } @Override public String toString() { return "长方形【长：" + length + " 宽：" + width + super.toString() + "】"; }}//测试类public class Test { public static void main(String[] args) { Geometric g = ________________________; //（10）利用上转型使父类对象指向圆类对象，使用无参构造 g = _________________________;//（11）利用上转型使父类对象指向长方形对象，使用无参构造 Rectangle re = new Rectangle(); if (g _______________________) { //（12）判断g是否属于长方形类 re = _____________________; //（13）对象下转型 }else { System.out.println("类型不匹配"); } }}