Saturday, January 27, 2007

XML UI's revisted (XAML, XUL and AJAX)

Back in October I made a post about WPF and my concerns around it. Now the European Committee for Interoperable Systems (ECIS), has raised similar concerns. To be fair some of the points raised by the people at the respectable Ars Technica site are valid on this point. Their article on this development raises many issues that indicate XAML (WPF) is not quite a full scale attack on standards (not yet anyway). A review of WPF at Wikipedia.

This was interesting news for me to wake up to since I have been thinking about XML based GUI's lately in relation to the Grails development I have been doing. Grails recently added OpenLaszlo as a build option for interfaces. (Ref:

The combination of XHTML and JavaSript to make user interfaces via AJAX that one can embedd into XHTML is currently all the rage. One can contrast this with XUL as yet another plus JavasScriptUI toolset. The process of embedding XUL UI's into XHTML might not be so clear to me at this time. Though perhaps XHTML in XUL is more likely anyway. I need to investigate this and also how CDF might play into this. Blending AJAX and XUL approaches might be an interesting gadonkin.

In the same manner that the grails generate-views command can be used to make XHTML interfaces the grails generate-laszlo is used to scaffold artifacts for Laszlo. So why not a grails generate-xul command? Indeed, as the Ars article points out it is hard to imagine anything that could compete with the ubiquitous presence of HTML. However, for web applications the ability to auto generate different UI's (XHTML, XUL, OpenLaszlo, etc) has some appeal. If this is done automatically from the domain classes with common class extensions to a set of scaffold'ed artifacts then a developer can simply worry about the application and the elements a UI needs and leave the final implementation of the UI up to the user. If the user wants XUL, then give that, if the user wants OpenLaszlo then give that. This might have more appeal yet as the web moves toward things like the iPhone, or the OpenMoko.

Also of note in that regard is the development of things like Wazaabi which brings XUL to the Eclipse RPC environment which can be used develop rich client applications. A friend of mine has used Eclipse RPC in his efforts related to work in Antarctica. :)

In conclusion I believe that the generation of richer UI's delivered across the web to browsers or brokered out to supporting apps by browsers is a developing trend. I'm interested to see how the Grails application framework could be used to generate XUL interfaces that are used from within Mozilla based browsers like Firefox. Combine this with the Mircoformats based semantics I have written previously about and I start to see a component framework built around Web standards and protocols. I need to build an example of some of this to truly investigate it.

Sunday, January 14, 2007


I was interested to see some news items that on the surface don't seem related but to me have a lot to say about trends.

Mozilla has started talking about Firefox 3 ( and in particular has mentioned microformats and a broader role for the browser as broker of information and service on the net to other applications. As a long time UNIX person I believe in the vision of small dedicated programs that do what they are meant to do and do it well tied together via piping. So the idea of data described by microformats, discovered or retrieved by broker and routed (piped) to other more dedicated applications has appeal to me.

Also of note was Songbird talking about plans for an API for site developers. I hope this evolves into a microformat or RDFa that allows a music centric site developer to place data directly into their web page that allows browsers like Songbird or even machine searching and indexing of music by the likes of Google or Singing Fish to use structured data from within a page or site.

This could get very exciting with things like Apple TV and The Venice Project (which is also using Mozilla technology) coming up and extending this possibility into video. With browsers getting more extensible and smarter about how they can handle structured data site developers will actually be able to see a reason (ie benefit) to doing something (anything) with metadata. Which to this point has has little to no use or benefit (IMHO).