code: private static ArrayList<File> getContentsInDirectoryTree(File directory, String includeMask, boolean returnFiles, boolean returnDirs) {
  		return getContentsInDirectoryTree(directory, new FileFilterRuleSet(directory.getPath()).setIncludeFilesWithNameMask(includeMask), returnFiles, returnDirs);
  	}
docs: Retrieves contents from a directory and its subdirectories matching a given mask.
  
  @param directory directory
  @param includeMask file name to match
  @param returnFiles return files
  @param returnDirs return directories
  @return a list containing the found contents