}
protected void serializeIdMap() throws OutputAlreadyExistsException, FileNotFoundException, IOException
{
File tmp = new File(rootDir, Constants.idMap);
if(tmp.exists()) throw(new OutputAlreadyExistsException(tmp.getAbsolutePath()));
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(tmp));
oos.writeObject(permutationIndex);
oos.close();
}