public static boolean registerCanonicalizer(final String c14nAlgorithmURI){
  final boolean added=canonicalizers.add(c14nAlgorithmURI);
  return added;
}

public static boolean registerCanonicalizer ( final String c14nAlgorithmURI ) { final boolean added = canonicalizers . add ( c14nAlgorithmURI ) ; return added ; }
this method allows to register a canonicalizer .
