code: public static boolean isCompleted(String operationState) {
          return operationState == null
                  || operationState.length() == 0
                  || SUCCEEDED.equalsIgnoreCase(operationState)
                  || isFailedOrCanceled(operationState);
      }
docs: Get whether or not the provided operation state represents a completed state.
  @param operationState The operation state to check.
  @return Whether or not the provided operation state represents a completed state.