function update(evt) {
        if (evt && evt.defaultPrevented) return;
        function check(rule) {
          var handled = rule($injector, $location);
          if (handled) {
            if (isString(handled)) $location.replace().url(handled);
            return true;
          }
          return false;
        }
        var n=rules.length, i;
        for (i=0; i<n; i++) {
          if (check(rules[i])) return;
        }
        // always check otherwise last to allow dynamic updates to the set of rules
        if (otherwise) check(otherwise);
      }
@ngdoc object
@name ui.router.router.$urlRouter

@requires $location
@requires $rootScope
@requires $injector

@description