阅读以下说明和Java代码,填充程序中的空缺,将解答填入答题纸的对应栏内。
【说明】
某应急交通控制系统(TraficControIS,stem)在红灯时控制各类车辆(Vehicle)的通
行,其类图如图6-1所示,在紧急状态下应急车辆在红灯时可通行,其余车辆按正常规
则通行。
下面的Java代码实现以上设计,请完善其中的空缺。
【Java代码】
abstract class Vehicle
public Vehicle () { }
abstract void run
};
interface Emergency {
(1) ;
(2) ;
}
class Car extends Vehicle {
public Car () { }
void run () { /*代码略*/ }
};
class Truck extends Vehicle {
public Truck () { }
void run () { /*代码略*/ }
class PoliceCar (3)
boolean isEmergency = false;
public PoliceCar () { }
public PoliceCar(boolean b) { this . isEmergency =b; }
public boolean isEmergent () { return (4); }
public void runRedLight () { /*代码略*/ }
}
/*类Ambulance. FireEngine实现代码略*/
public class TraficControISystem {/。交通控制类。/
private Vehicle[ ]V=new Vehiele [24];
int numVehicles;
public void control() {
for (int i=0; i if (v[i] instanceof Enu rgency&& ((Emergency)V [i]) isEmergent()) { ( 5 ) . runRedLigh': ( ) ; }else (6).run( ) } } void add (Vehicle vehicle) { v[numVehicles++]=vehicle;)/*添加车辆*/ void shutDown()(/*代码略*/} public static void main (Stri.ng [ ] args) { TraficControlSystem tcs = new TraficControlSystem() ; tcs . add (new Car () ; tcs .add (new PoliceCar () ; tcs .add (new Ambulance () ; tcs . add (new Ambulance (true》 ; tcs . add (new FireEngine ( true》 ; tcs . add (new Truck () ; tcs . add (new FireEngine ( ) ; tcs . control () ; tcs . shutDown () ; } }
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