Dynamic primefaces menuItem don't fire command - jsf

Question

Environment:
Java 7
Jboss 5.2
Primefaces 6.2
The problem I get is that when I click on the menu item the command does not fire the themeSwitcherBean.changeToOld method. What is wrong?
MenuModel menu = new DefaultMenuModel();
Create Menu
...
for (Iterator<Menu> it = children.iterator(); it.hasNext(); ) {
Menu subMenu = (Menu) it.next();
String index = subMenu.getCodi();
String element = rootCodi + index;
DefaultMenuItem menuItem = new DefaultMenuItem(menuName);
menuItem.setId(element);
menuItem.setUrl(subMenu.getServletPath());
menuItem.setCommand("#{themeSwitcherBean.changeToNew}");
menuItem.setUpdate(":content");
rootNode.addElement(menuItem);
}
menu.addElement(rootNode);
...
Menu.xhtml
<h:form id="frmMenu">
<pu:menu model="#{sessionBean.menu}">
</h:form>

Answer 1

If you set an URL to a menuItem.url property it is rendered as a simple hyperlink using href.
Clicking on this results in the browser to navigate to the given URL and request it using GET rather than doing a POST request optionally using AJAX.
This finally will not update ":content" the AJAX way and not invoke your themeSwitcherBean.changeToNew action method.
In order to have your action method invoke you have to skip that line:
menuItem.setUrl(subMenu.getServletPath());
If you find you need to reload the entire page (which is likely when switching themes) instead of the element referenced using ":content" only, make your action method return that instruction as String:
public String changeToNew() {
// do something ...
// ...
String viewId = FacesContext.getCurrentInstance().getViewRoot().getViewId();
return viewId + "?faces-redirect=true&includeViewParams=true";
}
In this case you can disable AJAX on that menu item reducing the request/response/javaScript overhead a little bit:
menuItem.setAjax(false);