shape.java

Java程序设计技巧与开发实例附书源代码。

public class Shape
    implements Sortable
{
   protected String name;
   protected double area, perimeter;

   public String toString()
   {
      return name + " [area = " + area + ", perimeter = " + perimeter + "]";
   }

   public void display()
   {
      System.out.println(toString());
   }

   public boolean lessThan(Sortable obj)
   {
      if (obj instanceof Shape)
      {
         return (area < ( (Shape) obj).area);
      }
      else
      {
         return false;
      }
   }
}