Wednesday, March 28, 2007

Setting the var attribute of dataTable in a facelet, part II

This time I take a completely different approach to this problem. The problem, by the way, is how to apply default Java Portlet API (JSR-168) CSS styles to the dataTable component. As shown in the previous post, this is complicated in Facelets by the fact that we can't just simply pass through a value for the var attribute of the dataTable component. But, this time that won't be an issue because we can simply extend the way Facelets handles the dataTable component and more directly apply the CSS styles we want.

After grepping through the Facelets source code, I discovered that HtmlComponentHandler is the TagHandler associated with the dataTable component (and all other HTML components as well). So I extended this with my own class, HtmlDataTableHandler:

package portletfacelets;

import javax.faces.component.UIComponent;
import javax.faces.component.html.HtmlDataTable;

import com.sun.facelets.FaceletContext;
import com.sun.facelets.tag.jsf.ComponentConfig;
import com.sun.facelets.tag.jsf.html.HtmlComponentHandler;

public class HtmlDataTableHandler extends HtmlComponentHandler {

public HtmlDataTableHandler(ComponentConfig config) {

protected void onComponentCreated(FaceletContext ctx,
UIComponent c, UIComponent parent) {
super.onComponentCreated(ctx, c, parent);
if (c instanceof HtmlDataTable) {
HtmlDataTable table = (HtmlDataTable) c;
if (table.getFooterClass() == null) {
if (table.getHeaderClass() == null) {
if (table.getRowClasses() == null) {
table.setRowClasses("portlet-section-body," +
if (table.getStyleClass() == null) {


I check if the classes are null, to allow the user of the TagHandler to override the styles, but that's about it. The facelets taglib entry looks like this:


I'm not sure which method I prefer, but I'm leaning toward the former, since it seems simpler and I like the idea of keeping things like CSS styles in a template file than in Java code, but in some sense this second approach also seems to be the cleaner one.

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