Block thread until callback method has been called by other thread

[James2000]

Hi All,

Please can you advise best way to block or suspend an application thread, until another thread has called a method in the application's class.

Thank you for your time and help,
Best regards,
James

public class ThreadTester {
  public static void main(String[] args) {
    new ThreadTester().application();
  }
  
  public void application() {
    for (int i=0; i<10; i++) {
      Thread t = new Thread(new Process(this, i));
      t.start();
      // wait here until serviceSearchCompleted() has been called by Process
    }
  }
  
  public void serviceSearchCompleted(int number) {
    System.out.println("Completed search " + number);
    // notify application() method to continue beyond 'waiting point'
  }
}



class Process implements Runnable {
  private ThreadTester threadTester;
  private int number;
  
  public Process(ThreadTester threadTester, int number) {
    this.threadTester = threadTester;
    this.number = number;
  }
  
  public void run() {
    startSearchServices();
  }
  
  private void startSearchServices() {
    System.out.println("Started search " + number);
    try {
      Thread.sleep(1000);  //...seaching...
    } catch (InterruptedException ie) {}
    threadTester.serviceSearchCompleted(number);
  }
}

[doWhile]

There are a great many ways. Set a flag and wait for it to be set by the Runnable, use Thread.join(), create a Semaphore...

[James2000]

Thank you for your reply. I have managed to RESOLVE this problem using the code below.

public class ThreadTester {
  private Object synchObj = new Object();

  public static void main(String[] args) {
    new ThreadTester().application();
  }
  
  public void application() {
    for (int i=0; i<10; i++) {
      Thread t = new Thread(new Process(this, i));
      t.start();
      synchronized (synchObj) {
        try { synchObj.wait(); } catch (InterruptedException ie) {}
      }
    }
  }
  
  public void serviceSearchCompleted(int number) {
    System.out.println("Completed search " + number);
      synchronized (synchObj) {
        synchObj.notify();
      }
  }
}



class Process implements Runnable {
  private ThreadTester threadTester;
  private int number;
  
  public Process(ThreadTester threadTester, int number) {
    this.threadTester = threadTester;
    this.number = number;
  }
  
  public void run() {
    startSearchServices();
  }
  
  private void startSearchServices() {
    System.out.println("Started search " + number);
    try {
      Thread.sleep(1000);  //...seaching...
    } catch (InterruptedException ie) {}
    threadTester.serviceSearchCompleted(number);
  }
}

[Norm]

Cross posted at Block thread until callback method has been called by other thread

Be sure to tell the other forums that you have solved this.

[DarrylBurke]

Also at
https://forums.oracle.com/forums/thr...readID=2388004
Block thread until callback method has been called by other thread (Threads forum at JavaRanch)

db