public Link getSelectedNavigationLink() {
   if (selectedNavigationLink == null) {
     for (Link link : getNavigationLinks()) {
       if (link.isSelected()) {
         selectedNavigationLink = link;
         break;
       }
     }
   }
   return selectedNavigationLink;
 }
 @Override
 public int compareTo(Link o) {
   return this.url.compareTo(o.getUrl());
 }