/**
* Retains only the elements in this collection that are contained in the specified collection (optional operation).
* @param CollectionInterface $collection
* @return boolean
*/
public function retainAll(CollectionInterface $collection)
{
$iterator = $this->iterator();
$changed = false;
while ($iterator->hasNext()) {
if (!$collection->contains($iterator->next())) {
$iterator->remove();
$changed = true;
}
}
return $changed;
}
