Hi,
In a for statement I want to start one thread for each element of the collection I'm iterating over, however I don't want them to actually run before the iteration is done.. That's what I'm doing now :
for (X x: listOfX){
Thread thread =new Thread(x);
thread.start();
}
Of course, X implements Runnable.
Thanks for help.
You can't control when the started threads actually start running.
What you can do is put some synchronization code in the Runnable to make sure no thread gets past a certain point until the main threads signals that the iteration is complete. You can use a CountdownLatch for this:
final CountDownLatch startSignal = new CountDownLatch(1);
// in the Runnable
public void run() {
try {
startSignal.await();
} catch (InterruptedException ex) {
// choose how to respond eg return or throw Error
}
// real work of the Runnable
}
// main thread
for (X x: listOfX) {
Thread thread = new Thread(x);
thread.start();
}
startSignal.countDown(); // release all the started threads
Of course there is still no guarantee about the ordering - but no thread passes the latch until the main thread says it is okay.