@Override
 public Collection<? extends GrantedAuthority> getAuthorities() {
   Collection<GrantedAuthority> grantedAuthorities = new HashSet<GrantedAuthority>();
   for (UserRole role : this.getUserRoles()) {
     grantedAuthorities.add(new SimpleGrantedAuthority(role.getRoleName()));
   }
   return grantedAuthorities;
 }