我是否正确地使用了UML图？

Question

问题：我是否正确制作了这个UML图？

UML图表：

环

• -radius：double

• + PI：double

• + setRadius（rad：double）：void

• + getRadius（rad：double）：void
• + getArea（）：double
• + getDiameter（）：double
• + getCircumference（）：double

代码：

 public class Circle
{

  //Declaration
  private double radius;
  public static final double PI = 3.14159; 


  public Circle()
 {
  radius = 0.0;
 }
    public Circle(double rad)
   {
       radius = rad;
     }

   /**
     The setRadius method stores a value in the
     radius field.
      @param rad The value to store in radius.
   */

  public void setRadius(double rad)
   {
      radius = rad;
  }
    /**
     The getRadius method returns a Radius
     for the Circle.
     @return The entered radius in the radius field.
   */
    public double getRadius(double rad)
    {
  return radius;
   }
    /**
     The getArea method returns an Area
    for the Circle.
     @return The Area for the Circle.
   */
   public double getArea()
   {
     return PI * (radius * radius);
   }
     /**
     The getDiameter method returns a diameter
     for the Circle.
     @return The diameter for the Circle.
   */