arttrace.java

这一些程序都是实验之用

interface Shape{
	void draw();
	void erase();
	}

class Circle implements Shape{
	public void draw(){
	System.out.println("Circle.draw()");
		         }
	public void erase(){
	System.out.println("Circle.erase()");
		    }
    }

class Square implements Shape{					//all of the shape implements of shape class 
	public void draw(){
	System.out.println("Square.draw()");		//implement the method of shape
			}
	public void erase(){
	System.out.println("Square.erase()");
	}
}

 class Triangle implements Shape{
	public void draw(){
	System.out.println("Triange.draw()");
	}
	public void erase(){
	System.out.println("Triangle.erase()");
	 }
  }
     
    	
public class ArtTrace{
	
	public static Shape factory(String which)throws BadShapeException{
		if(which.equalsIgnoreCase("Circle")){
			Circle c=new Circle();
			c.draw()	;
			return new Circle();
		}else if(which.equalsIgnoreCase("Square")){
			Square s=new Square();
			s.draw();
		return new Square();
		}else if(which.equalsIgnoreCase("Triangle")){
		Triangle t=new Triangle();
			t.draw();
		return new Triangle();
		}else{
		throw new BadShapeException(which);
     		 }
	         }
	}
	
class BadShapeException extends Exception
{
	public BadShapeException(String msg){super(msg);}
}


class use_implements {
public void use(){
	try{
	ArtTrace art=new ArtTrace();
	art.factory("Circle");	
	art.factory("Square");
	art.factory("Triangle");
	art.factory("Diamond");
     }catch(BadShapeException e){
System.out.println("did not exist the shape what you want draw");
}
}
public static void main(String args[]){
	use_implements ui=new use_implements();
	ui.use();
 }
}