Question

I am running a for loop and at each iteration, I execute a SwingWorker in background (who lasts around 5 minutes).
I have an attribute who is the number of Worker running in background at the same time.

The for loop has 100 iterations but I want only 5 simulutaneous SwingWorker running. How can I pause the loop iteration if the number of simulutaneous worker running if superior to 5 ? how can I resume it when it becomes lower ?

Thank you.

Answer 1

Normally I use an ExecutionService with 5 threads to do this. But you can use a Semaphore like this.

 final Semaphore permits = new Semaphore(5);
 for(int i=0;i<100;i++) {
     permits.acquire();
     // add a task
 }



 // in the SwingWorker
 public String doInBackground() {
     try {
        return findTheMeaningOfLife();
     } finally {
        permits.release();
     }
 }