public static String buildDocRefPathString(final Collection<DocRef> path) {
        if (NullSafe.isEmptyCollection(path)) {
            return "";
        } else {
            return path.stream()
                    .filter(Objects::nonNull)
                    .map(DocRef::getDisplayValue)
                    .collect(Collectors.joining(NODE_PATH_STRING_DELIMITER));
        }
    }
@return True if this node's set of {@link NodeFlag}s is missing ALL the flags in nodeFlags.
stroom-core-shared/src/main/java/stroom/explorer/shared/ExplorerNode.java