异常练习1

/*
有一个圆形和长方形，都可以获取面积，对于面积，如果出现非法数值，
视为获取面积出现问题。问题通过异常来表示。
*/

class NoValueException extends RunTimeException{
	NoValueException(String messgae){
		super(message);
	}
}

interface Shape{
	void getArea();
}

class Rec implements Shape{
	private int len,wid;
	Rec(int len,int wid){
		if(len<=0 || wid<=0)
			throw new NoValueException("出现非法数值");
		this.len = len;
		this.wid = wid;
	}
	public void getArea(){
		System.out.println(len * wid);
	}
}

class Circle implements Shape{
	private int radius;
	public static final double PI = 3.14;
	Circle(int radius){
		if(radius <= 0)
			throw new NoValueException("非法半径");
		this.radius = radius;
	}
	public void getArea{
		System.out.println(radius*radius*PI)
	}
}

class ExceptionTest1{
	public static void main(String[] args){
		Rec r = new Rec(3,4);
		r.getArea();
		
		Circle c = new Circle(-2);
		
		System.out.println("over");
			
	}
}