JSF in the XPages Jakarta EE Support Project

Feb 11, 2022, 2:31 PM

Tags: jakartaee jsf
  1. Updating The XPages JEE Support Project To Jakarta EE 9, A Travelogue
  2. JSP and MVC Support in the XPages JEE Project
  3. Migrating a Large XPages App to Jakarta EE 9
  4. XPages Jakarta EE Support 2.2.0
  5. DQL, QueryResultsProcessor, and JNoSQL
  6. Implementing a Basic JNoSQL Driver for Domino
  7. Video Series On The XPages Jakarta EE Project
  8. JSF in the XPages Jakarta EE Support Project
  9. So Why Jakarta?
  10. XPages Jakarta EE 2.5.0 And The Looming Java-Version Wall
  11. Adding Concurrency to the XPages Jakarta EE Support Project
  12. Adding Transactions to the XPages Jakarta EE Support Project
  13. XPages Jakarta EE 2.9.0 and Next Steps
  14. XPages JEE 2.11.0 and the Javadoc Provider
  15. The Loose Roadmap for XPages Jakarta EE Support
  16. XPages JEE 2.12.0: JNoSQL Views and PrimeFaces Support
  17. XPages JEE 2.13.0
  18. XPages JEE 2.14.0
  19. XPages JEE 2.15.0 and Plans for JEE 10 and 11

When I talked about adding Jakarta NoSQL to the JEE support project, I mentioned how that in a way completed the pitch for this project as a full development mechanism. With data access and MVC+JSP in place, now it provides tools to build REST-based or server-rendered UIs backed cleanly by Domino data. Neat!

But, much like I had previously danced around the question of data access, there was still a spectre lurking in the background, a long-standing part of the Java/Jakarta EE platform: JSF, now named Jakarta Server Faces. This has unsurprisingly been gnawing at the back of my mind, since "upgrade JSF" has been one of the longest-running requests for XPages, starting basically right after JSF 1.2 came out with a smattering of technologies XPages didn't get.

While the notion of un-forking XPages is intriguing, it's its own big pile of work, and not in this project's bailiwick to address. What this project can do, though, is bring current JSF to an NSF alongside XPages. This proposition has a lot going on, so I think it'll be worth discussing both the practical elements and the implications.

How Is JSF Doing Nowadays, Anyway?

To start out with, it will be instructive to look at how JSF has fared since XPages split off from it in the JSF 1.1 era. We'll use the version history from Wikipedia as a starting point:

  1. 2004 - JSF 1.0
  2. 2004 - JSF 1.1 (minor release)
  3. 2006 - JSF 1.2 (feature release, included in Java EE)
  4. 2009 - JSF 2.0 (major release with significant improvements)
  5. 2010 - JSF 2.1 (minor release)
  6. 2013 - JSF 2.2 (feature release)
  7. 2017 - JSF 2.3 (feature release)

So... this is a real mixed bag, huh? Since XPages, JSF received a few major feature releases, progressing to 2.3. But, uh, the gaps in the years, though - that's ominous. And 2017 was the last feature update? Hrm.

But wait - when I tweeted about it, the screenshot says "JSF 4.0". What's going on there?

Well, like all active JEE specs, Faces received a major-version bump for semantic-versioning purposes when moving to the jakarta.* namespace. Version 3.0 came out in 2020, but was functionally identical to 2.3 from 2017, just with the API package names changed.

After that point, though, the future is in the Eclipse Foundation's hands, and each Jakarta spec is deciding its fate for future releases. Some specs, like JSP, are focusing on non-breaking releases that focus on just a handful of fixes and clarifications. Faces, though, seems to have be the focus of some pent-up desires for change that are coming to fruition now that there's headroom for it.

Faces 4.0 gets another major-version bump because it involves some breaking changes that go beyond just the package names, including outright removing old deprecated features in favor of better modern options. Beyond that, it gains some outright new features - not the sort of features that would change a developer's life, but useful stuff.

Does this mean that JSF is in the prime of its life? Well, time will tell, and merely having developers settle what was presumably very old business doesn't guarantee a vibrant future, but it's a nice sign. In any event, it's not dead, so it has that going for it. Plus, the repositories for "ecosystem" libraries like PrimeFaces and Tobago are quite active, which is important.

So Is It Good? Is This How We Should Write Apps?

Maybe! I'm not sure. I mean, there's no getting around the general popularity of client-JS-first app dev, and the server side of that is covered well by JAX-RS. That said, current popularity isn't everything when it comes to development: it's all about the problems it solves. For the type of development usually done for Domino, server-side apps fit quite well, and even an exceedingly-adept developer can often get results quicker in an integrated stack of this type.

In any event, I expect I'll give it a shot for a bit and see how it shakes out.

How Does This Even Work? Doesn't It Conflict With XPages?

I'm glad you asked! Part of the problem I'd tangled with with this project from the start was that the aging versions of the various JEE specs - and the XPages JSF fork - are essentially unmovable obstacles. If I want to have a project that enhances Domino in place rather than replacing it in whole or in part, I have to deal with the stuff that's there.

Fortunately, like with pseudo-updating the core Servlet spec, the javax.*-to-jakarta.* namespace move is my savior. Honestly, being a trademark stickler may be the best thing Oracle's ever done from my perspective. Thanks to this switch, all the concerns API-side about distinguishing versions disappeared. While I might know that javax.faces.context.FacesContext and jakarta.faces.context.FacesContext are competing versions of the same spec, Java doesn't know - they're completely unrelated.

However, as with some other components, the API isn't the whole story. While the API packages all changed for Jakarta EE 9, the implementations generally kept their original packages. XPages is based on the original JSF implementation, which is now Mojarra over at Eclipse. This implementation uses the com.sun.faces namespace. While most of the XPages-specific stuff is under com.ibm.xsp, all those Sun-branded classes are still floating around, like com.sun.faces.RIConstants and com.sun.faces.context.FacesContextImpl. Moreover, XPages still uses com.sun.faces prefixes for stored application properties. For example, there's an ApplicationAssociate object that Sun-JSF and XPages use to keep track of app-specific information, and it stashes this in the conceptual NSF application. Using Mojarra, these sorts of classes and properties conflict, and things got hairy, with me trying to stash the com.sun stuff to the side per-request, with only partial success.

Fortunately, Mojarra isn't the only game in town: Apache MyFaces is alive and well, including with an actively-developed 4.0 branch. This implementation does not derive from the original, and doesn't use the com.sun.faces namespace. As an intriguing tidbit, Notes (but not Domino) actually includes MyFaces 1.1; I'm guessing it's another thing in there to support some kind of "Social" foofaraw.

Anyway, MyFaces was my ticket to success. Not only did it remove the problem of needing to walk on eggshells with package and attribute names, but the fact that it's a wholly-different implementation removed some of the other weird problems I was dealing with from the table.

Required Infrastructure Improvements

Unlike some of the more staid specs (like JSP) or cutting-edge ones (like MVC and NoSQL), both JSF implementations lean heavily on Servlet-spec features that showed up after Domino's 2.4 implementation. While they fortunately don't require filters, they do heavily use listeners of many stripes.

So, like when I had to hack together RequestDispatcher support to implement MVC, I had to do similarly here to support attribute listeners and manually kick of lifecycle event notifications.

I realize I'm kind of baking my way into making a full Servlet 5 container on top of Domino's rickety old one. There's way more work to make that an actual thing, but it's intriguing seeing it take shape just as incidental work from implementing other parts.

Next Steps

For the next steps, I'm not quite sure. For what it is, I think it's all working pretty well. However, while JSF on its own provides a lot of functionality, it's stuff like the component libraries from PrimeFaces that makes it a full toolkit. In a normal case, the server itself wouldn't provide component packs like PrimeFaces or Tobago - the app itself would bring them in as Maven/etc. dependencies and they would be included as part of the WAR. This would probably work in an NSF, but the experience of developing in an NSF when you have JARs in the classpath is... not great. Accordingly, I'm pondering including one or both of those in the project. It'd have tradeoffs, but it might make sense, or maybe it'd make sense to have associated projects that package them as distinct libraries to include. We'll see.

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