I was able to get uPortal version 2.0 working, and It looks nice. It seems they have spent alot of effort on the presentation/templating layer (they use xslt), and I can see why it would be popular for aggregating a bunch of legacy systems.
It's interesting to note that it seems very similar in structure to dotLRN portlets, except uPortal has a more polished appearance. I don't think it would be too difficult to recreate the uPortal functionality in openacs/dotLRN.
In order to have a seamless integration for a channel, it seems that it would be necessary to use either a servlet, or an applet based channel. I've always disliked applets, as they invariably crash my browser, and they take too long to download, if they have any significant functionality. Therefore, I think the servlet based channel approach would be the best method for implementing a new channel to dotLRN.
Servlets could use a variety of methods for collecting the channel data, but I think the web-services approach is the best way to create a channel, and I think it wouldn't be too hard to do so using existing open-source tools like the apache axis soap implementation.
The axis projects is a follow-on to the apache soap project, and it has been architected to be modular. It provides for callbacks in the request and response phases of a soap transaction, and it also allows for the use of multiple transport layers for transporting soap messages. It should be possible to hook in aolserver as the transport layer for axis (residing in nsjava), and export dotLRN functionality via webservices. Since uPortal is a servlet application, an axis soap client could be easily integrated with uPortal. The bulk of the work would probably be in developing the uPortal channel servlet application. Lately, I've been interested in providing web-services for openacs, and I will attempt to tie the axis transport layer to aolserver in the near future (as soon as I get the new version of OpenFTS out the door), and see if I can implement a general web-service package using nsjava.
