A: JBoss 4.2.1.GA comes with JSF 1.2 RI (Reference Implementation) and by default registers JBossJSFConfigureListener class as a context listener for any web app you deploy. To see how this is done, look at the web.xml file under <jboss dir>\ server\ default\ deploy\ jboss-web.deployer\ conf\ directory. The above web.xml is common to all web applications you deploy which means that JBossJSFConfigureListener gets a chance to participate in your web application lifecycle events, such as when the context is initialized and when the context is destroyed.

When the servlet container starts your web application and calls contextInitialized() method on JBossJSFConfigureListener, the listener starts its initialization process. However, it delegates most of the initialization process to the JSF RI default context listener ConfigureListener. The JSF RI ConfigureListener scans for all available faces configuration files (faces-config.xml) and uses the collected information to configure your JSF application.

For a typical Seam 2.0.0.CR3 deployment, I compiled a list of common faces-config.xml files which the JSF RI ConfigureListener uses to configure your JSF application.

As ConfigureListener works its way through all of the above configuration files and configures the necessary classes, it follows an interesting strategy when there are two or more classes registered for the same configuration. For example, FaceletViewHandler, SeamViewHandler, AjaxViewHandler and ViewHandlerImpl are all registered as a view handler from three different faces-config.xml files. In this case, ConfigureListener instantiates each of these classes and passes an instance of the previous class to the next one. Therefore, when ConfigureListener creates an instance of AjaxViewHandler it passes an instance of ViewHandlerImpl to the constructor of AjaxViewHandler and when it creates an instance of SeamViewHandler it passes the already created instance of AjaxViewHandler to the constructor of SeamViewHandler. Finally, when it creates an instance of FaceletViewHandler, it passes the already created instance of SeamViewHandler to the constructor of FaceletViewHandler.

When ConfigureListener is done with its initialization process, you should expect the following classes to have been instantiated:

As you can see, Seam was able to hookup with JSF by providing the necessary factories and other classes in the faces-config.xml files. I hope that you found the above information useful!

I wrote this blog with the following versions in mind:
JBoss version: 4.2.1.GA
JSF version: JSF 1.2 (Implementation-Version: 1.2_04-b16-p02)
Seam version: 2.0.0.CR3

Design a single page wizard using JBoss Seam 2.0.x. This wizard should handle its operations using one xhtml page. The wizard starts by retrieving information from the database, the information retrieved depends on a URL query parameter that was used to access the page. The wizard should then solicit for a user input and perform an action once the input is submitted. This action might require database interaction. The wizard displays the result on the same page after redirecting. If there is an error detected, the user is redirected to the same page with an error message. The wizard page shall be accessible only if the user is logged in.

I am starting a series of blog entries centered around JBoss Seam. These entries reflect my own experience working with Seam which I would like to share with the rest of the world! Please stay tuned!