code: public String getValue(int i) {
          if (i < 0 || i >= values.size()) {
              return null;
          }
          return values.get(i);
      }
docs: Get the value of an attribute (by position).
  
  @param i The position of the attribute in the list.
  @return The attribute value as a string, or null if
  there is no attribute at that position.
  @see org.xml.sax.AttributeList#getValue(int)