code: protected CmsDefaultStringModel getUrlNameModel(String urlName) {
  
          if (m_urlNameModel == null) {
              m_urlNameModel = new CmsDefaultStringModel("urlname");
              m_urlNameModel.setValue(urlName, false);
          }
          return m_urlNameModel;
      }
docs: Lazily creates the model object for the URL name field.<p>
  
  @param urlName the initial value for the URL name
  
  @return the model object for the URL name field