circle1.java

《Java面向对象程序设计》例子源代码.轻松学习书本.

//Circle1.java
public class Circle1 extends Point1 {
   private double radius;  
   public Circle1(){
   	  //隐式地调用超类Point1的无参构造函数
      System.out.println( "Circle1 no-argument constructor: " + this );
   } 
   public Circle1( int xValue, int yValue, double radiusValue ){
      super( xValue, yValue );   	//显式地调用超类的带两个参数的构造函数
      setRadius( radiusValue );
      System.out.println( "Circle1 constructor: " + this );
   } 
   protected void finalize(){
      System.out.println( "Circle1 finalizer: " + this );
      super.finalize(); 			//调用超类的finalize方法 
   }
   public void setRadius( double radiusValue ){
      radius = ( radiusValue < 0.0 ? 0.0 : radiusValue );
   } 
   public double getRadius(){
      return radius;
   } 
   public double getDiameter(){
      return 2 * getRadius();
   } 
   public double getCircumference(){
      return Math.PI * getDiameter();
   } 
   public double getArea(){
      return Math.PI * getRadius() * getRadius();
   } 
   public String toString(){
      return "Center = " + super.toString() + "; Radius = " + getRadius();
   } 
}