Practical RichFaces, Second Edition

CHAPTER 1 THE BASICS
As you can see, usually you won’t be working with HTML markup directly. You will simply use
components that render the entire necessary markup.
A note on rendering other markup languages. In the early days of JSF, the idea that components can
render different markup based on client device was an interesting one. At that time, the mobile devices
available usually worked with markup languages such as XML or WML. Today the situation is very
different. Most modern mobiles devices, such as smart phones and tablets, come with powerful
browsers supporting all the latest HTML, JavaScript, and CSS features. In some cases, the browser on a
mobile device is better than the one on a PC. This means that generation markup other than HTML is no
longer as important or has simply faded with the availability of mobile phones and other devices that
support HTML.
This doesn’t mean that renderers no longer play an important role. Even though HTML is now
supported on various devices, renderers still play a role in regards to the kind of markup (HTML) that is
generated. With the explosion of mobile devices, we now have to develop applications for a large
number of different screen sizes. There is only so much “content” (or real estate) that can fit on a mobile
phone with a 3.5-inch screen, or a tablet with a 7-inch screen, or even on a large laptop screen. This is
exactly where renderers can help. Based on the device, screen size, and even screen resolution, the
renderers can provide different markup.
Events
JSF takes you beyond the request/response paradigm and provides a powerful event-based model. The
UI components that you use to build the user interface are sending events (when activated or clicked) to
the server (browser events such as click are mapped to server-side component events). Listeners then
process the events. For example, clicking a button (which is a UI component) is an event that is
processed by an appropriate listener. (The JSF event-based model offers an approach to UI development
similar to other user interface frameworks such as Swing and Flex.)
For instance, in the #{simpleBean.save} expression defined in an action attribute, save is a
method inside simpleBean bean. It is usually referred to as a JSF action and will be invoked when the
button is clicked:
Before we continue, you need to be familiar with the JSF life-cycle phases shown in Figure 1-5 and
need to understand what each phase does. We will be using this same diagram to show RichFaces
concepts. Make sure you understand what each phase does and what happens to the flow in case of a
conversion/validation error or when using the immediate="true" attribute. Understanding the life cycle
can also help with debugging your JSF applications with phase listeners. You will be using a phase
listener later in this book. In case you need to brush up on JSF phases, this article at Javabeat
(www.javabeat.net/articles/54-request-processing-lifecycle-phases-in-jsf-1.html) is a good place
to do that.