code: public ProvFormat getTypeForFile(String filename) {
          int count = filename.lastIndexOf(".");
          if (count == -1)
              return null;
          String extension = filename.substring(count + 1);
          return extensionRevMap.get(extension);
      }
docs: Get a {@link ProvFormat} given the file's exetension
  @param filename the file for which the {@link ProvFormat} is sought
  @return a {@link ProvFormat}