Controlling race condition at startup.
- by Will Hartung
I have some code that I want to have some one time initialisation performed. But this code doesn't have a definite lifecycle, so my logic can be potentially invoked by multiple threads before my initialisation is done. So, I want to basically ensure that my logic code "waits" until initialisation is done.
This is my first cut.
public class MyClass {
private static final AtomicBoolean initialised = new AtomicBoolean(false);
public void initialise() {
synchronized(initialised) {
initStuff();
initialised.getAndSet(true);
initialised.notifyAll();
}
}
public void doStuff() {
synchronized(initialised) {
if (!initialised.get()) {
try {
initialised.wait();
} catch (InterruptedException ex) {
throw new RuntimeException("Uh oh!", ex);
}
}
}
doOtherStuff();
}
}
I basically want to make sure this is going to do what I think it's going to do -- block doStuff until the initialised is true, and that I'm not missing a race condition where doStuff might get stuck on a Object.wait() that will never arrive.
Edit:
I have no control over the threads. And I want to be able to control when all of the initialisation is done, which is why doStuff() can't call initialise().
I used an AtomicBoolean as it was a combination of a value holder, and an object I could synchronize. I could have also simply had a "public static final Object lock = new Object();" and a simple boolean flag. AtomicBoolean conveniently gave me both. A Boolean can not be modified.
The CountDownLatch is exactly what I was looking for. I also considered using a Sempahore with 0 permits. But the CountDownLatch is perfect for just this task.
