Ordering threads to run in the order they were created/started

Question

How can i order threads in the order they were instantiated.e.g. how can i make the below program print the numbers 1...10 in order.

public class ThreadOrder         


        

Answer 1

Control of thread execution order may be implemented quite easily with the semaphores. The code attached is based on the ideas presented in Schildt's book on Java (The complete reference....). // Based on the ideas presented in: // Schildt H.: Java.The.Complete.Reference.9th.Edition.

import java.util.concurrent.Semaphore;

class Manager {
    int n;
// Initially red on semaphores 2&3; green semaphore 1.
    static Semaphore SemFirst = new Semaphore(1);
    static Semaphore SemSecond = new Semaphore(0);
    static Semaphore SemThird = new Semaphore(0);

void firstAction () {
    try {
        SemFirst.acquire();
    } catch(InterruptedException e) {
        System.out.println("Exception InterruptedException catched");
    }
    System.out.println("First: " );
    System.out.println("-----> 111");
    SemSecond.release();
}
void secondAction() {
    try{
        SemSecond.acquire();
    } catch(InterruptedException e) {
        System.out.println("Exception InterruptedException catched");
    }
    System.out.println("Second: ");
    System.out.println("-----> 222");
    SemThird.release();
}
void thirdAction() {
    try{
        SemThird.acquire();
    } catch(InterruptedException e) {
        System.out.println("Exception InterruptedException catched");
    }
    System.out.println("Third: ");
    System.out.println("-----> 333");
    SemFirst.release();
}
}

class Thread1 implements Runnable {
    Manager q;

    Thread1(Manager q) {
    this.q = q;
    new Thread(this, "Thread1").start();
}

public void run() {
    q.firstAction();
}
}

class Thread2 implements Runnable {
    Manager q;

    Thread2(Manager q) {
    this.q = q;
    new Thread(this, "Thread2").start();
}

public void run() {
    q.secondAction();
}
}

class Thread3 implements Runnable {
    Manager q;

    Thread3(Manager q) {
    this.q = q;
    new Thread(this, "Thread3").start();
}

public void run() {
    q.thirdAction();
}
}

class ThreadOrder {
    public static void main(String args[]) {
    Manager q = new Manager();
    new Thread3(q);
    new Thread2(q);
    new Thread1(q);
    }
}