private boolean moveToNext() {
try {
Notification<? extends T> nextNotification = observer.takeNext();
if (nextNotification.isOnNext()) {
isNextConsumed = false;
next = nextNotification.getValue();
return true;
}
// If an observable is completed or fails,
// hasNext() always return false.
hasNext = false;
if (nextNotification.isOnCompleted()) {
return false;
}
if (nextNotification.isOnError()) {
error = nextNotification.getThrowable();
throw Exceptions.propagate(error);
}
throw new IllegalStateException("Should not reach here");
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
error = e;
throw Exceptions.propagate(error);
}
}
@Override
public T next() {
if (error != null) {
// If any error has already been thrown, throw it again.
throw Exceptions.propagate(error);
}
if (hasNext()) {
isNextConsumed = true;
return next;
} else {
throw new NoSuchElementException("No more elements");
}
}
@Override
public boolean hasNext() {
if (error != null) {
// If any error has already been thrown, throw it again.
throw Exceptions.propagate(error);
}
// Since an iterator should not be used in different thread,
// so we do not need any synchronization.
if (hasNext == false) {
// the iterator has reached the end.
return false;
}
if (isNextConsumed == false) {
// next has not been used yet.
return true;
}
return moveToNext();
}