I just saw this demo: http://java.dzone.com/videos/filthy-rich-portlets and am unable to figure out how to do the same with vaadin.
I am looking for an unbiased opinion.
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Is it really possibly to achieve ICEFaces like IPC with Vaadin?
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The ICEPush mechanism (used in the demo) has already been integrated to Vaadin. And luckily it has even new version available advertising portlet support:
http://vaadin.com/addon/icepush
If I understand correctly this requires you to have the portlets in the same war.
Otherwise, there is nothing special in Vaadin in this. Several ways of doing IPC that you might consider, if this is not suitable for you. Unfortunately all IPC mechanisms (I know about) seem to have some limitation.