The create_temporary_directory beanshell creates a temporary directory and outputs the path to that directory.
The empty directory is examined by the List_files_by_regex service. Since there are no files, an empty list is output.
File temp = File.createTempFile("taverna", ".dir");
temp.delete();
temp.mkdir();
temp.deleteOnExit();
directoryPath = temp.getCanonicalPath();
directoryPath
.*c.*
net.sourceforge.taverna.scuflworkers.io.FileListByRegexTask