public Collection<InvalidProperty> process(Map<String, String> properties) { List<InvalidProperty> result = new Vector<InvalidProperty>(); final String files = properties.get(XmlTestConstants.SETTINGS_FILES); final String project = properties.get(XmlTestConstants.SETTINGS_PROJECT); if (PropertiesUtil.isEmptyOrNull(project) && PropertiesUtil.isEmptyOrNull(files)) { result.add( new InvalidProperty( XmlTestConstants.SETTINGS_FILES, "Files or project option must be specified")); } return result; }