Hi all,

 I'm looking at different frameworks like JBoss Portal, GridSphere,
etc. but some opinion of any of you who has an experience with
frameworks would be helpful.

 The most important requirement for the final system that will be
built on the framework is an easy way that the end-user can create his
own 'sub-portal' with predefined pages and an access to the predefined
'components' he can embed on those 'sub-portal' pages. Both - pages
(i.e. home, guestbook, history) and 'components' are predefined by the
system (portal, framework) but the user can fully customize their look
and feel even by replacing the default HTML code with his own.

The idea is similar to the way the blog platforms work: you can create
your own blog, once you do it, you get a list of predefined pages like
main, new comment, guest book, archive, etc.

The important thing is that you can completely change the HTML code of
those predefined pages within your blog.

You also get a set of 'components' or 'tags' like {blog}, {nick},
{guestbook}, etc. and you may embed them in your predefined pages
using HTML - as you wish. The content provided by these 'components'
is of course predefined by the blog platform so you can change only
look and feel of them.

So - which of the available opensource java-based frameworks/portals
could be the best to implement the functionality described above?

Thanks in advance for your opinions,
Tomasz