public AjaxResponse replaceNumbers(AjaxActionEvent event) {
String number = new Integer((new Random()).nextInt()).toString();
// Create the text component holding the number:
SimpleText text = new SimpleText(number);
// Create an ajax action for replacing all previously set numbers:
ReplaceContentAction action = new ReplaceContentAction("num", text);
// Create a concrete ajax response:
AjaxResponse response = new AjaxResponseImpl();