@Override
    // TODO: fix this when/if NOT_FOUND is no longer a success.
    public boolean isSuccess() { return super.isSuccess() || outcome() == Outcome.NOT_FOUND; }
This response is provided for successful document update operations. Use the
wasFound() method to check whether or not the document was actually found.

@author Simon Thoresen Hult
documentapi/src/main/java/com/yahoo/documentapi/UpdateResponse.java