code: @Override
    @SuppressWarnings("unchecked")
    public void visit(final Visitable visitable) {
      if (visitable instanceof Identifiable) {
        ((Identifiable<T>) visitable).setId(getIdentifierSequence().nextId());
      }
    }
docs: Visits any {@link Visitable} objects implementing the {@link Identifiable} interface and assigns
  a unique ID from the sequence.
  
  @param visitable the Visitable object visited by this Visitor.
  @see org.cp.elements.lang.Identifiable#setId(Comparable)
  @see org.cp.elements.lang.Visitable
  @see #getIdentifierSequence()