// loop.
try {
// Record exceptions so that if we fail to obtain any
// result, we can throw the last exception we got.
ExecutionException ee = null;
long lastTime = timed ? System.nanoTime() : 0;
Iterator<? extends Callable<T>> it = tasks.iterator();
// Start one task for sure; the rest incrementally
futures.add(ecs.submit(it.next()));
--ntasks;
int active = 1;
for (;;) {
Future<T> f = ecs.poll();
if (f == null) {
if (ntasks > 0) {
--ntasks;
futures.add(ecs.submit(it.next()));
++active;
} else if (active == 0) {
break;
} else if (timed) {
f = ecs.poll(nanos, TimeUnit.NANOSECONDS);
if (f == null) {
throw new TimeoutException();
}
long now = System.nanoTime();
nanos -= now - lastTime;
lastTime = now;
} else {
f = ecs.take();
}
}
if (f != null) {
--active;
try {
return f.get();
} catch (ExecutionException eex) {
ee = eex;
} catch (RuntimeException rex) {
ee = new ExecutionException(rex);
}
}
}
if (ee == null) {
ee = new ExecutionException(null);
}
throw ee;
} finally {
for (Future<T> f : futures) {
f.cancel(true);