/* 
 *1.手動(dòng)拋出一個(gè)異常的例子
 */
public class TestException3 {
	public static void main(String[] args) {
		Circle c1 = new Circle(2.1);
		Circle c2 = new Circle(2.1);
		System.out.println(c2.compareTo(c2));
		System.out.println(c1.compareTo(new String("44")));
	}
}
class Circle{
	private double radius;
	public Circle(double radius) {
		super();
		this.radius = radius;
	}
	public double getRadius() {
		return radius;
	}
	public void setRadius(double radius) {
		this.radius = radius;
	}
	//比較兩個(gè)圓的半徑誰(shuí)大
	public int compareTo(Object obj) {
		if(this == obj) {
			return 0;
		}
		else if(obj instanceof Circle) {
			Circle c = (Circle)obj;
			if(this.radius > c.radius) {
				return 1;
			}else if(this.radius == c.radius){
				return 0;
			}else {
				return -1;
			}
		}else {
			//因?yàn)樵谶@里返回聲明都不適合，手動(dòng)的拋出一個(gè)異常
			//運(yùn)行時(shí)異?？梢圆挥蔑@示處理，在運(yùn)行的時(shí)候，拋出。
			throw new RuntimeException("傳入的類型有誤");
//			throw new Exception("傳入的類型有誤");
			//非RuntimeException必須在出現(xiàn)的時(shí)候顯示處理
		}
	}
}

  @Override
  public void registerObserver(Observer o) {
    if (o == null){
      throw new NullPointerException("o is a null object");
      return; //需要么？
    }
    this.mList.add(o);
  }

//代碼1
public static void test() throws Exception {
  throw new Exception("參數(shù)越界"); 
  System.out.println("異常后"); //編譯錯(cuò)誤，「無(wú)法訪問(wèn)的語(yǔ)句」
}

//代碼2
try{
  throw new Exception("參數(shù)越界"); 
}catch(Exception e) {
  e.printStackTrace();
}
System.out.println("異常后");//可以執(zhí)行

//代碼3
if(true) {
  throw new Exception("參數(shù)越界"); 
}
System.out.println("異常后"); //拋出異常，不會(huì)執(zhí)行