SpinLock – 1

My simple Spinlock implementation with 2 CAS operations (non Peterson’s algorithm, with busy non-CAS waiting), without limit of spins. Still have problems with code plugin, sorry.

import java.util.concurrent.Callable;
import java.util.concurrent.atomic.AtomicBoolean;

public class SpinLock<V> {

private final AtomicBoolean lock = new AtomicBoolean(false);

public V executeWithSpinLock(Callable<V> e) throws Exception {
while (true) {
// Busy non-CAS waiting until lock will be free.
while (alreadyLocked()) {
}
if (!lock()) {
// We didn’t acquire lock… another thread did it before us.
continue;
}
// We took the lock. Let’s do the work and unlock in finally-block.
try {
return e.call();
} finally {
unlock();
}
}
}

private boolean alreadyLocked() {
return lock.get();
}

private boolean lock() {
return lock.compareAndSet(false, true);
}

private void unlock() {
lock.compareAndSet(true, false);
}
}