how to set boolean flag of thread-1 from thread-2 in Java multithreading

Question

I am writing a simple multithreaded application that involves three threads: Thread-1, Thread-2 and main.

Answer 1

I would have the main() routine create a new AtomicBoolean object, and I would pass references to the object to the constructors of both Thread classes. The RunningAvg.run() method can set the AtomicBoolean, and the NumGen.run() method can examine it.

class NumGen extends Thread {
    ...
    AtomicBoolean isDone;

    public NumGen(PipedOutputStream pos, AtomicBoolean isDone){
        ...
        this.isDone = isDone;
    }

    public void run(){
        while (!isDone.get()){
            ...
        }
    }
}

class RunningAvg extends Thread {
    ...
    AtomicBoolean isDone;

    public RunningAvg(PipedInputStream pis, AtomicBoolean isDone){
        ...
        this.isDone = isDone;
    }

    public void run(){
        try {
        while (dis.available()>0){
            ...
            if (avg > 1E5) {
                isDone.set(true);
                ...
            }
        }
        ...
    }


public class InterThreadComm {

    public static void main(String[] args){

    try {
        ...
        AtomicBoolean isDone = new AtomicBoolean(false);
        NumGen ng = new NumGen(pos, isDone);
        RunningAvg ra = new RunningAvg(pis, isDone);
        ...
    }