@Override
 @SuppressWarnings("unchecked")
 public ProtocolWaveletOperationJsoImpl getOperation(int n) {
   initArray(this, keyOperation);
   JsArray<ProtocolWaveletOperationJsoImpl> array = getPropertyAsObject(this, keyOperation).cast();
   if (n < 0) throw new IllegalArgumentException("index " + n + " < 0");
   if (array.length() <= n)
     throw new IllegalArgumentException("index " + n + ">= array length " + array.length());
   return array.get(n);
 }