jsr372-experts@javaserverfaces-spec-public.java.net

[jsr372-experts] Annotation to enable/configure JSF?

From: arjan tijms <arjan.tijms_at_gmail.com>
Date: Tue, 15 Dec 2015 14:41:23 +0100

Hi,

One of two ways to automatically enable JSF in a project is having either a
class on the class path annotated with one of the JSF native annotations,
or having a /WEB-INF/faces-config.xml file present.

With the world moving to CDI, the JSF native annotations (specifically
@MangedBean) are not so much used anymore. This way to enable JSF is not so
practical anymore.

A faces-config.xml file is still a simple way, if it wasn't for the fact
that officially (if I'm not mistaken) it can't be just an empty file like
CDI's bean.xml. Looking up the right schema for trivial applications is a
bit of a hassle.

I was thinking that instead of using existing JSF annotations that as a
side-effect enable JSF, it might be worth looking into a JSF annotation
that is specifically intended to enable JSF.

E.g.

@ActivateJSF
public class JustAClass {

}

The name "ActivateJSF" is just an example and could be any other name. Some
other candidates @JSF, @JSFConfig, @JSFActivation, @ActivateFaces,
@FacesConfig, @FacesParams, etc

In the simplest version this will just activate JSF like @ManagedBean does,
but without the side effect of also creating a (potentially unused) managed
bean.

One step further may be to add some configuration options, potentially the
annotation variant of the various web.xml settings.

E.g.

@ActivateJSF(
    stateSavingMethod = "server"
)

Or a new option, to indicate the JSF version:

@ActivateJSF(
    version = "2.3" // enables all JSF 2.3 features
)

@ActivateJSF(
    version = "2.2" // behaves as much as possible as 2.2 did
)

Yet another step further, if the class on which @ActivateJSF appears is a
CDI bean, alternatives can be used to switch configuration.

I experimented with this locally in the Mojarra source code, and in some
experiments it worked quite nicely.

Thoughts?

Kind regards,
Arjan Tijms