Raible Designs

Integrating JSF and Tapestry into AppFuse

Well it looks like I accomplished my goal for the year: integrate Spring MVC, WebWork, Tapestry and JSF into AppFuse. I decided to integrate JSF and Tapestry at the same time so I could get a good feel for their differences. Also, I figured there would be a lot of similarities I could re-use between the two. I found this to be a great idea. Often I'd use the first framework as a template and the second would go much quicker. It turned out to be a good strategy because I often found bugs in the first while working on the second. I really enjoyed developing with both JSF and Tapestry - here's my notes from my development marathon over the last week:

Tapestry

• For Tapestry, I created a patched version of the 3.0 source. I did this because I wanted some non-standard things, like friendly URLs, a global properties file and a popup calendar that works with IE/XHTML. The Tapestry Community was gracious enough to supply the source - so I didn't have to do much patching myself.
• Pure HTML, like Tapestry has, is ssoooooo much nicer to work with. The syntax highlighting in HomeSite is fully functional again! I've been an HTML developer since 94 and I felt like it was 97 all over again - when we didn't write apps, just static HTML.
• Overriding the default Tapestry ValidationDelegate was pretty easy - and there's even an example in Tapestry in Action. I was able to add asterisks for required fields and error messages next to the fields fairly easily. Erik Hatcher also hooked me up with a Label component for non-validating fields.
• For the contrib:Table component, you can easily i18n column headings by using "keyName:propertyName" as the column value. However, if your keyName has a period in it (i.e. user.username), you can't override the ValueBlock b/c user.username is an invalid OGNL expression. I patched Tapestry to solve this.
• The ability to use <span key="keyName"/> to render i18n keys is awesome. So simple.
• Tapestry has a very rich validation framework that requires virtually no configuration. No setting up your resource bundle, etc. It just works. Client-side too.
• It would be nice to show all the client-side validation errors in a single dialog instead of one-at-a-time (WebWork does this too).

JSF/MyFaces

• I like how you don't have to create mappings - just link to the .jsp with an .html extension.
• For some reason, when I save a user and server-side validation occurs, the user's username and roles disappear. Good thing client-side validation is available.
• It was easy to override the Labels to add asterisks thanks to some code from David Geary on the MyFaces mailing list. In order to make it work, I had to ditch my HTML <table> and use an <h:panelGrid>. Now my JSP is Tag Soup. I think JSF is going to have to ditch JSP if they want to get anywhere. Hopefully JSF will soon support HTML templates like Tapestry and parse them with a Servlet Filter or something.
• It's unfortunate that I have to specify a "styleClass" attribute on all my <h:message> tags - I'd like to just set a default for these tags (others too).
• I ditched JSF's message setting and opted for setting my own List of messages in the session and then grabbing them out with a MessageFilter. This was so much easier to implement than the standard JSF message setting stuff.
• I'd rather not have to specify <f:loadBundle> at the top of each page. It's going to be the same for my whole app - it'd be nice to set a default bundle and variable name that all tags could access.
• It was quite a bit easier to integrate JSF into AppFuse than Tapestry. This was mainly due to the fact that I could re-use a lot of the JSP code, as well as the WebWork Actions are pretty close to the JSF Managed Beans.
• Spring Rocks - it never caused any issues with either framework. I just wish MyFaces wouldn't warn that it can't find a variable that it's already found. I had to turn logging down to FATAL so I don't get any meaningless messages from MyFaces.
• With JSF, why do I have to specify the supported locales in faces-config.xml? Why can't it look up the available bundles like JSTL with Spring/WebWork/Struts does?

So after all of this, which is my favorite? Unfortunately, there is no clear winner. They're both pretty cool, but not that much better than Struts, Spring or WebWork. In reality, I like them all, that's why they're all integrated into AppFuse!

Update: I forgot to mention that I was very pleased with the latest version of Canoo's WebTest. It now uses HtmlUnit at its core and its JavaScript support has vastly improved. I wouldn't have been able to do integration testing on the JSF version without this (updated) library. Not only did it work great, but it found XHTML issues in my code - that rocks! The JSF and Tapestry versions of AppFuse are the only ones that run Canoo tests with JavaScript turned on. This is mainly because the old tests worked fine w/o JavaScript and I didn't want to break them.