* @see org.jasig.portal.url.IPortalUrlProvider#getPortletUrlByFName(javax.servlet.http.HttpServletRequest, java.lang.String)
*/
public IPortalPortletUrl getPortletUrlByFName(HttpServletRequest request, String portletFName) {
//Get the user's layout manager
final IUserInstance userInstance = this.userInstanceManager.getUserInstance(request);
final IUserPreferencesManager preferencesManager = userInstance.getPreferencesManager();
final IUserLayoutManager userLayoutManager = preferencesManager.getUserLayoutManager();
//Determine the subscribe ID
final String channelSubscribeId = userLayoutManager.getSubscribeId(portletFName);
if (channelSubscribeId == null) {
throw new IllegalArgumentException("No channel subscribe ID found for fname '" + portletFName + "'.");