Apache Wicket Component Based Web Development Framework

Wicket Agenda: What is Wicket? Why use Wicket? Core Wicket Concepts There is an overwhelming number of Java web frameworks available today, primarily distinguished by two main groups, Traditional – or – request based (Struts, Spring MVC…) and Component Based (Wicket, Tapestry...). What is Wicket? Why use Wicket? Core Wicket Concepts A few Wicket examples

What is Wicket? Open Source Component Based Pure Java & HTML Enables component oriented, programmatic manipulation of markup Pure Java & HTML Clean separation of Java and HTML The mission: bringing object oriented programming to the web application view layer

Why use Wicket? Integration State management Clustering support Spring Guice Hibernate and more… State management Clustering support Back button support

Why use Wicket cont.. Ajax support without writing JavaScript! Integration with some JavaScript libraries such as jQuery URL Mounting Pretty URLs Component Level Security

Core Wicket Concepts: Pages & Panels The four most important wicket concepts that require understanding by any user, are Session, Components, Models, and Behaviors. Without these four main concepts you cannot manage dataflow throughout your wicket application. Pages & Panels Session Components Models Behaviors

Pages & Panels Page: Panel A representation of what is to be displayed to the user when the page is loaded. Consists of HTML & Java May contain 1 … N panels Panel Reusable displayable component

Wicket and Sessions Stores Session specific data Locale, client info Wicket’s Session is an implementation of java’s HttpSession. Stores Session specific data Locale, client info Logged in user Shopping cart contents Page history and back button support And whatever else you need to maintain..

Sessions are EASY with Wicket class MySession extends WebSession { private ShoppingCart cart; public ShoppingCart getCart() { … } public void setCart(ShoppingCart cart) { … } } mysession.setCart(new ShoppingCart()); The sessions is accessible from ALL pages / panels

Components! The ultimate superclass! Encapsulate the programmatic manipulation of markup. May receive events onClick, onSubmit, etc.. Know how and when to render themselves

How components work. HTML Markup Java Code <h1 wicket:id=“title”/> <input wicket:id=“firstName”/> Behaviors: <button wicket:id=“addUser" type="submit" class="positive“> <b>Add User</b></button> new Label(“title”, “It’s a Title!”); new TextField(“firstName", new PropertyModel(user, " firstName ")); Behaviors new Button(" addUser ", new Model<String>("Add User")) { @Override public void onSubmit() { // do something here!!! }

Component Validation Input validation is key in all web applications, fortunately Wicket makes this easy! TextField phoneNumberInput = new TextField("phoneNumberInput", new PropertyModel(currentUser, "phoneNumber")); phoneNumberInput.setRequired(true) .add(new StringValidator.ExactLengthValidator(10)) .add(new PatternValidator("[0-9]*"));

Creating your own Components Wicket is designed and intended for extension, if the provided components don’t do EXACTLY what you want, you can easily extend any of them!

<<Person>> Wicket Models Models bind your POJO’s to Wicket components Label(“name”, model) <<Person>> +name : String +city : String PropertyModel

Example Models: PropertyModel: In Code: new PropertyModel(person, “name”) new PropertyModel(person, “address.street”) In Code: Person person = new Person(); new TextField(“firstName", new PropertyModel(person, "firstName"));

Examples and Q & A