* @return the theme name
     * @throws ThemeException if theme name cannot be determined
     */
    protected String getThemeName(final Artifact artifact) {
        final String themeName = artifact.getName().substring(ArtifactType.THEME.getId().length() + 1);
        if (StringUtil.isBlank(themeName)) {
            throw new ThemeException("Theme name is empty: " + artifact);
        }
        return themeName;