UIColumn header = headers.next();
writer.startElement("th", component);
writer.writeAttribute("class", cellClass, null);
UIComponent facet = header.getFacet("header");
if (facet != null && facet.isRendered()) {
facet.encodeBegin(facesContext);
if (facet.getRendersChildren()) {
facet.encodeChildren(facesContext);
} else {
renderer.renderChildren(facesContext, facet);
}