var BicycleFactory = {createBicycle: function(model) {var bicycle;switch(model) {case 'The Speedster':bicycle = new Speedster();break;case 'The Lowrider':bicycle = new Lowrider();break;case 'The Flatlander':bicycle = new Flatlander();break;case 'The Comfort Cruiser':default:bicycle = new ComfortCruiser();}Interface.ensureImplements(bicycle, Bicycle);return bicycle;}
};

var BicycleShop = function() {};
BicycleShop.prototype = {sellBicycle: function(model) {var bicycle = BicycleFactory.createBicycle(model);bicycle.assemble();bicycle.wash();return bicycle;}
};

var BicycleShop = function() {};
BicycleShop.prototype = {sellBicycle: function(model) {var bicycle;switch(model) {case 'The Speedster':bicycle = new Speedster();break;case 'The Lowrider':bicycle = new Lowrider();break;case 'The Comfort Cruiser':default:bicycle = new ComfortCruiser();}Interface.ensureImplements(bicycle, Bicycle);bicycle.assemble();bicycle.wash();return bicycle;}
};

var BicycleShop = function() {};
BicycleShop.prototype = {sellBicycle: function(model) {var bicycle = this.createBicycle(model);bicycle.assemble();bicycle.wash();return bicycle;},createBicycle: function(model) {throw new Error('Unsupported operation on an abstract class.');}
};

var AcmeBicycleShop = function() {};
extend(AcmeBicycleShop, BicycleShop);
AcmeBicycleShop.prototype.createBicycle = function(model) {var bicycle;switch(model) {case 'The Speedster':bicycle = new AcmeSpeedster();break;case 'The Lowrider':bicycle = new AcmeLowrider();break;case 'The Flatlander':bicycle = new AcmeFlatlander();break;case 'The Comfort Cruiser':default:bicycle = new AcmeComfortCruiser();}Interface.ensureImplements(bicycle, Bicycle);return bicycle;
};

var GeneralProductsBicycleShop = function() {};
extend(GeneralProductsBicycleShop, BicycleShop);
GeneralProductsBicycleShop.prototype.createBicycle = function(model) {var bicycle;switch(model) {case 'The Speedster':bicycle = new GeneralProductsSpeedster();break;case 'The Lowrider':bicycle = new GeneralProductsLowrider();break;case 'The Flatlander':bicycle = new GeneralProductsFlatlander();break;case 'The Comfort Cruiser':default:bicycle = new GeneralProductsComfortCruiser();}Interface.ensureImplements(bicycle, Bicycle);return bicycle;
};

/* DisplayModule interface. */var DisplayModule = new Interface('DisplayModule', ['append', 'remove', 'clear']);/* ListDisplay class. */var ListDisplay = function(id, parent) { // implements DisplayModulethis.list = document.createElement('ul');this.list.id = id;parent.appendChild(this.list);
};
ListDisplay.prototype = {append: function(text) {var newEl = document.createElement('li');this.list.appendChild(newEl);newEl.innerHTML = text;return newEl;},remove: function(el) {this.list.removeChild(el);},clear: function() {this.list.innerHTML = '';}
};/* Configuration object. */var conf = {id: 'cnn-top-stories',feedUrl: 'http://rss.cnn.com/rss/cnn_topstories.rss',updateInterval: 60, // In seconds.parent: $('feed-readers')
};/* FeedReader class. */var FeedReader = function(display, xhrHandler, conf) {this.display = display;this.xhrHandler = xhrHandler;this.conf = conf;this.startUpdates();
};
FeedReader.prototype = {fetchFeed: function() {var that = this;var callback = { success: function(text, xml) { that.parseFeed(text, xml); }, failure: function(status) { that.showError(status); } };this.xhrHandler.request('GET', 'feedProxy.php?feed=' + this.conf.feedUrl, callback);},parseFeed: function(responseText, responseXML) {this.display.clear();var items = responseXML.getElementsByTagName('item');for(var i = 0, len = items.length; i < len; i++) {var title = items[i].getElementsByTagName('title')[0];var link = items[i].getElementsByTagName('link')[0];this.display.append('<a href="' + link.firstChild.data + '">' + title.firstChild.data + '</a>');}},showError: function(statusCode) {this.display.clear();this.display.append('Error fetching feed.');},stopUpdates: function() {clearInterval(this.interval);},startUpdates: function() {this.fetchFeed();var that = this;this.interval = setInterval(function() { that.fetchFeed(); }, this.conf.updateInterval * 1000);}
};/* FeedManager namespace. */var FeedManager = {createFeedReader: function(conf) {var displayModule = new ListDisplay(conf.id + '-display', conf.parent);Interface.ensureImplements(displayModule, DisplayModule);var xhrHandler = XhrManager.createXhrHandler();Interface.ensureImplements(xhrHandler, AjaxHandler);return new FeedReader(displayModule, xhrHandler, conf);}
};