/** {@inheritDoc} */
 public boolean checkCollection(String id) {
   if (storage.checkCollection(id)) {
     return true;
   }
   ContentEntity ce = getVirtualChild(id, getRealParent(id), true);
   if (ce != null) {
     if (id.equals(ce.getId())) {
       if (ce instanceof ContentCollection) {
         return true;
       }
     }
   }
   return false;
 }