square.java

用java实现的枚举类型和实现长方形的程序！在机子上编绎并且通过！！很实用！

public interface Colorable{
   public abstract void howToColor();
}
abstract class GeometricObject{
  private String color="yellow";
  private boolean filled;
  protected GeometricObject(){
  }
  protected GeometricObject(String color,boolean filled){
     this.color=color;
     this.filled=filled;
  }
  public String getColor(){
     return color;
  }
  public void setColor(){
     this.color=color;
  }
  public boolean isFilled(){
       return filled;
  }
  public void setFilled(boolean filled){
        this.filled=filled;
  }
  public abstract double getPerimeter();
}
class Square extends GeometricObject implements Colorable{
    public String howTocolor(){
      return "color it red";
    }
}
/*class Color implements Colorable{
     public String howToColor(){
          return "color it green";
     }
}*/
class green extends Color{
     public String howToColor(){
         return "color it green";
     }
}
class blue extends Color{
     public String howToColor(){
         return "color it blue";
     }
}
public class TestColor{
      public static void main(String[] args){
        Object[] objects={new blue(),new green()};
        for(int i=0;i<objects.length;i++)
          showObject(objects[i]);
      } 
      public static void showObject(Object object){
         if(object instanceof Colorable)
             System.out.println((Colorable)object).howToColor());
      }
}