Я пытаюсь создать программу моделирования, в которой:
- банка передается на конвейер
- банка заполнена
- банка проверена
- если банка повреждена, она будет удалена с конвейера
ошибки:
Exception in thread "RealtimeThread[pri=20,aperiodic]"
java.lang.NullPointerException
at assignment$Sensor.run(assignment.java:99)
at javax.realtime.RealtimeThread$Logic.run(RealtimeThread.java:244)
at javax.realtime.MemoryArea.enter(MemoryArea.java)
at javax.realtime.MemoryArea.enterInternal(MemoryArea.java:1472)
at javax.realtime.RealtimeThread$Logic.run(RealtimeThread.java:230)
Я хочу использовать AsyncEventHandler для запускакод, если банка повреждена, но выдает ошибку NullPointerException, если банка обнаружена поврежденной с первой попытки, однако код работает нормально, если банка не повреждена в первом цикле.
import java.util.Random;
import javax.realtime.*;
public class realtime{
AsyncEvent damage;
public static void main(String[] args) {
realtime a = new realtime();
}
public realtime() {
Can can = new Can(1);
Conveyer conveyer = new Conveyer(can);
Sensor Sensor = new Sensor(can);
Grabber grabber = new Grabber(can, Sensor);
ReleaseParameters relConveyer = new PeriodicParameters(new RelativeTime(1000,0));
ReleaseParameters relSensor = new PeriodicParameters(new RelativeTime(1000,0));
conveyer.setReleaseParameters(relConveyer);
Sensor.setReleaseParameters(relSensor);
conveyer.start();
Sensor.start();
damage = new AsyncEvent();
damage.setHandler(grabber);
}
class Can {
int id;
boolean filled;
boolean damaged;
public Can(int id) {
this.id = id;
}
public void isFilled(boolean status) {
this.filled = status; //Print if the Can is filled
}
public void isDamaged(boolean status) {
this.damaged = status;
}
}
class Conveyer extends RealtimeThread {
Can can;
Random random = new Random();
public Conveyer(Can can) {
this.can = can;
}
@Override
public void run() { //While loop can be used to repeat
while(true) {
System.out.println("Can " + can.id + " has entered the conveyer");
System.out.println("Can " + can.id + " is being filled");
can.isFilled(true); //Sleep to give time to fill
System.out.println("Can " + can.id + " is filled");
System.out.println("Can " + can.id + " is being scanned");
can.isDamaged(random.nextBoolean());
try {
waitForNextRelease();
}
catch (Exception e) {}
}
}
}
class Sensor extends RealtimeThread{
Can can;
public Sensor(Can can) {
this.can = can;
}
@Override
public void run() { //While loop can be used to repeat
while(true) {
if(can.damaged) {
System.out.println("Can " + can.id + " is Damaged!");
damage.fire();
} else {
System.out.println("Can " + can.id + " is moved to Stage 2");
}
try {
waitForNextRelease();
}
catch (Exception e) {}
}
}
}
class Grabber extends AsyncEventHandler {
Can can;
RealtimeThread rtt;
boolean damaged = false;
public Grabber(Can can, RealtimeThread rtt) {
this.can = can;
this.rtt = rtt;
}
public void handleAsyncEvent() {
System.out.println("Can " + can.id + " is disposed");
}
}
}