code: public final void openTableHead(THeadTag.State state, AbstractRenderAppender appender) {
          if(state == null)
              state = THEAD_STATE;
  
          if(_theadRenderer == null)
              _theadRenderer = TagRenderingBase.Factory.getRendering(TagRenderingBase.THEAD_TAG, _request);
  
          appender.append(LINE_BREAK);
          _theadRenderer.doStartTag(appender, state);
      }
docs: /* -------------------------------------------------------------
  
  Table Row Group Rendering
  
  -------------------------------------------------------------