private void validateRouting(Tuple2<File, String> directory) throws IOException {
        if ( ! directory.first.isDirectory()) return;
        validateRouting(validators.routingStandaloneXmlValidator(), directory);
    }
Validation of xml files in application package against RELAX NG schemas.

@author hmusum
config-application-package/src/main/java/com/yahoo/config/model/application/provider/ApplicationPackageXmlFilesValidator.java