function $UrlRouterProvider(  $urlMatcherFactory) {
  var rules = [], 
      otherwise = null;

  // Returns a string that is a prefix of all strings matching the RegExp
  function regExpPrefix(re) {
    var prefix = /^\^((?:\\[^a-zA-Z0-9]|[^\\\[\]\^$*+?.()|{}]+)*)/.exec(re.source);
    return (prefix != null) ? prefix[1].replace(/\\(.)/g, "$1") : '';
  }

  // Interpolates matched values into a String.replace()-style pattern
  function interpolate(pattern, match) {
    return pattern.replace(/\$(\$|\d{1,2})/, function (m, what) {
      return match[what === '$' ? 0 : Number(what)];
    });
  }

  /**
   * @ngdoc function
   * @name ui.router.router.$urlRouterProvider#rule
   * @methodOf ui.router.router.$urlRouterProvider
   *
   * @description
   * Defines rules that are used by `$urlRouterProvider to find matches for
   * specific URLs.
   *
   * @example
   * <pre>
   * var app = angular.module('app', ['ui.router.router']);
   *
   * app.config(function ($urlRouterProvider) {
   *   // Here's an example of how you might allow case insensitive urls
   *   $urlRouterProvider.rule(function ($injector, $location) {
   *     var path = $location.path(),
   *         normalized = path.toLowerCase();
   *
   *     if (path !== normalized) {
   *       return normalized;
   *     }
   *   });
   * });
   * </pre>
   *
   * @param {object} rule Handler function that takes `$injector` and `$location`
   * services as arguments. You can use them to return a valid path as a string.
   *
   * @return {object} $urlRouterProvider - $urlRouterProvider instance
   */
  this.rule =
    function (rule) {
      if (!isFunction(rule)) throw new Error("'rule' must be a function");
      rules.push(rule);
      return this;
    };

  /**
   * @ngdoc object
   * @name ui.router.router.$urlRouterProvider#otherwise
   * @methodOf ui.router.router.$urlRouterProvider
   *
   * @description
   * Defines a path that is used when an invalied route is requested.
   *
   * @example
   * <pre>
   * var app = angular.module('app', ['ui.router.router']);
   *
   * app.config(function ($urlRouterProvider) {
   *   // if the path doesn't match any of the urls you configured
   *   // otherwise will take care of routing the user to the
   *   // specified url
   *   $urlRouterProvider.otherwise('/index');
   *
   *   // Example of using function rule as param
   *   $urlRouterProvider.otherwise(function ($injector, $location) {
   *     ...
   *   });
   * });
   * </pre>
   *
   * @param {string|object} rule The url path you want to redirect to or a function 
   * rule that returns the url path. The function version is passed two params: 
   * `$injector` and `$location` services.
   *
   * @return {object} $urlRouterProvider - $urlRouterProvider instance
   */
  this.otherwise =
    function (rule) {
      if (isString(rule)) {
        var redirect = rule;
        rule = function () { return redirect; };
      }
      else if (!isFunction(rule)) throw new Error("'rule' must be a function");
      otherwise = rule;
      return this;
    };


  function handleIfMatch($injector, handler, match) {
    if (!match) return false;
    var result = $injector.invoke(handler, handler, { $match: match });
    return isDefined(result) ? result : true;
  }

  /**
   * @ngdoc function
   * @name ui.router.router.$urlRouterProvider#when
   * @methodOf ui.router.router.$urlRouterProvider
   *
   * @description
   * Registers a handler for a given url matching. if handle is a string, it is
   * treated as a redirect, and is interpolated according to the syyntax of match
   * (i.e. like String.replace() for RegExp, or like a UrlMatcher pattern otherwise).
   *
   * If the handler is a function, it is injectable. It gets invoked if `$location`
   * matches. You have the option of inject the match object as `$match`.
   *
   * The handler can return
   *
   * - **falsy** to indicate that the rule didn't match after all, then `$urlRouter`
   *   will continue trying to find another one that matches.
   * - **string** which is treated as a redirect and passed to `$location.url()`
   * - **void** or any **truthy** value tells `$urlRouter` that the url was handled.
   *
   * @example
   * <pre>
   * var app = angular.module('app', ['ui.router.router']);
   *
   * app.config(function ($urlRouterProvider) {
   *   $urlRouterProvider.when($state.url, function ($match, $stateParams) {
   *     if ($state.$current.navigable !== state ||
   *         !equalForKeys($match, $stateParams) {
   *      $state.transitionTo(state, $match, false);
   *     }
   *   });
   * });
   * </pre>
   *
   * @param {string|object} what The incoming path that you want to redirect.
   * @param {string|object} handler The path you want to redirect your user to.
   */
  this.when =
    function (what, handler) {
      var redirect, handlerIsString = isString(handler);
      if (isString(what)) what = $urlMatcherFactory.compile(what);

      if (!handlerIsString && !isFunction(handler) && !isArray(handler))
        throw new Error("invalid 'handler' in when()");

      var strategies = {
        matcher: function (what, handler) {
          if (handlerIsString) {
            redirect = $urlMatcherFactory.compile(handler);
            handler = ['$match', function ($match) { return redirect.format($match); }];
          }
          return extend(function ($injector, $location) {
            return handleIfMatch($injector, handler, what.exec($location.path(), $location.search()));
          }, {
            prefix: isString(what.prefix) ? what.prefix : ''
          });
        },
        regex: function (what, handler) {
          if (what.global || what.sticky) throw new Error("when() RegExp must not be global or sticky");

          if (handlerIsString) {
            redirect = handler;
            handler = ['$match', function ($match) { return interpolate(redirect, $match); }];
          }
          return extend(function ($injector, $location) {
            return handleIfMatch($injector, handler, what.exec($location.path()));
          }, {
            prefix: regExpPrefix(what)
          });
        }
      };

      var check = { matcher: $urlMatcherFactory.isMatcher(what), regex: what instanceof RegExp };

      for (var n in check) {
        if (check[n]) {
          return this.rule(strategies[n](what, handler));
        }
      }

      throw new Error("invalid 'what' in when()");
    };

  /**
   * @ngdoc object
   * @name ui.router.router.$urlRouter
   *
   * @requires $location
   * @requires $rootScope
   * @requires $injector
   *
   * @description
   *
   */
  this.$get =
    [        '$location', '$rootScope', '$injector',
    function ($location,   $rootScope,   $injector) {
      // TODO: Optimize groups of rules with non-empty prefix into some sort of decision tree
      function update(evt) {
        if (evt && evt.defaultPrevented) return;
        function check(rule) {
          var handled = rule($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);
      }

      $rootScope.$on('$locationChangeSuccess', update);

      return {
        /**
         * @ngdoc function
         * @name ui.router.router.$urlRouter#sync
         * @methodOf ui.router.router.$urlRouter
         *
         * @description
         * Triggers an update; the same update that happens when the address bar url changes, aka `$locationChangeSuccess`.
         * This method is useful when you need to use `preventDefault()` on the `$locationChangeSuccess` event, 
         * perform some custom logic (route protection, auth, config, redirection, etc) and then finally proceed 
         * with the transition by calling `$urlRouter.sync()`.
         *
         * @example
         * <pre>
         * angular.module('app', ['ui.router']);
         *   .run(function($rootScope, $urlRouter) {
         *     $rootScope.$on('$locationChangeSuccess', function(evt) {
         *       // Halt state change from even starting
         *       evt.preventDefault();
         *       // Perform custom logic
         *       var meetsRequirement = ...
         *       // Continue with the update and state transition if logic allows
         *       if (meetsRequirement) $urlRouter.sync();
         *     });
         * });
         * </pre>
         */
        sync: function () {
          update();
        }
      };
    }];
}
@ngdoc object
@name ui.router.router.$urlRouterProvider

@requires ui.router.util.$urlMatcherFactoryProvider

@description
`$urlRouterProvider` has the responsibility of watching `$location`. 
When `$location` changes it runs through a list of rules one by one until a 
match is found. `$urlRouterProvider` is used behind the scenes anytime you specify 
a url in a state configuration. All urls are compiled into a UrlMatcher object.

There are several methods on `$urlRouterProvider` that make it useful to use directly
in your module config.