public void addFiles(Collection<String> files){
  checkFileNames(files);
  for (  String f : files) {
    setFiles.add(namedForThisSegment(f));
  }
}

public void addFiles ( Collection < String > files ) { checkFileNames ( files ) ; for ( String f : files ) { setFiles . add ( namedForThisSegment ( f ) ) ; } }
add these files to the set of files written for this segment .
