code: protected void parseDefaultType( TokenStream tokens,
                                       JcrNodeDefinitionTemplate childDefn ) throws ConstraintViolationException {
          if (tokens.canConsume('=')) {
              if (!tokens.canConsume('?')) {
                  Name defaultType = parseName(tokens);
                  childDefn.setDefaultPrimaryTypeName(string(defaultType));
              }
          }
      }
docs: Parse the child node definition's default type, if they appear next on the token stream.
  
  @param tokens the tokens containing the definition; never null
  @param childDefn the child node definition; never null
  @throws ParsingException if there is a problem parsing the content
  @throws ConstraintViolationException not expected