Hi, Christophe!
I actually know some JSF too, so don't let my recent Vaadin focus throw you!
As I've said before, I think Vaadin can be a good framework when you have to crank out a business portlet quickly. I don't think it's a good fit if you need a lot of eye candy, for example.
It tends to be difficult for theming as you will first invest in your Liferay theme, get that all just the way you want it, but then you have to go back and repeat for your Vaadin theme (because they do things differently).
Vaadin portlets have some weird hangups that can be hard to wrap your head around, such as the need to specify a height value at the highest widget level, lest the portlet not display.
Although the Vaadin framework supports push for servlets, it (the last time I checked) does not support push in portlets, so if you need push you'd have to use another path.
If you think it's hard finding good JSF resources, it's about 50 times harder in the US (Vaadin has a bigger foothold in Europe so I don't think the odds are that hard there).
The Vaadin Add Ons are great in that they extend the Vaadin core, but some (many) have issues integration into the portal. For example, my next blog post started to use the High Charts add on until I realized that it had embedded jQuery and was using the $ nomenclature, something that fails on Liferay. Fortunately the source was available and I ended up rebuilding the Add On to be portal-friendly and finished what should have been a simple pie chart portlet, but I was prepared for those kinds of issues where many others would have thrown up their hands.
All of that said, it can be a good fit at times. For example, I walked into an organization that needed some portlets created yet the development team was limited to java developers. They spent years building B2B java servlets and had no experience with the latest Web development stuff such as HTML5, CSS3, AJAX, Responsive, etc. They didn't have folks with strengths in CSS styling or JavaScript framework coding. I found Vaadin to be a great fit for them, they could build fast portlets that performed well in the browser completely in Java.
Your environment is probably a bit different, if you have JSF already it might be easier to stick with that.
I see Vaadin as being just another option for portlet development, but there's not a great deal of examples or push out there to get the word out. For certain situations, I think Vaadin is a great choice, but without any blogs, forum posts, or google hits on it folks might not be aware of it as an option.
So I guess the shorter response I could have given was "No, don't discard what you know but, if you have time, take a look at it and maybe add it to your tool belt if there's room".
With every tool I add to my belt, I find myself figuring out how to do things in better ways than I had before, even when using more familiar tools. Learning new things keeps you fresh
I actually know some JSF too, so don't let my recent Vaadin focus throw you!
As I've said before, I think Vaadin can be a good framework when you have to crank out a business portlet quickly. I don't think it's a good fit if you need a lot of eye candy, for example.
It tends to be difficult for theming as you will first invest in your Liferay theme, get that all just the way you want it, but then you have to go back and repeat for your Vaadin theme (because they do things differently).
Vaadin portlets have some weird hangups that can be hard to wrap your head around, such as the need to specify a height value at the highest widget level, lest the portlet not display.
Although the Vaadin framework supports push for servlets, it (the last time I checked) does not support push in portlets, so if you need push you'd have to use another path.
If you think it's hard finding good JSF resources, it's about 50 times harder in the US (Vaadin has a bigger foothold in Europe so I don't think the odds are that hard there).
The Vaadin Add Ons are great in that they extend the Vaadin core, but some (many) have issues integration into the portal. For example, my next blog post started to use the High Charts add on until I realized that it had embedded jQuery and was using the $ nomenclature, something that fails on Liferay. Fortunately the source was available and I ended up rebuilding the Add On to be portal-friendly and finished what should have been a simple pie chart portlet, but I was prepared for those kinds of issues where many others would have thrown up their hands.
All of that said, it can be a good fit at times. For example, I walked into an organization that needed some portlets created yet the development team was limited to java developers. They spent years building B2B java servlets and had no experience with the latest Web development stuff such as HTML5, CSS3, AJAX, Responsive, etc. They didn't have folks with strengths in CSS styling or JavaScript framework coding. I found Vaadin to be a great fit for them, they could build fast portlets that performed well in the browser completely in Java.
Your environment is probably a bit different, if you have JSF already it might be easier to stick with that.
I see Vaadin as being just another option for portlet development, but there's not a great deal of examples or push out there to get the word out. For certain situations, I think Vaadin is a great choice, but without any blogs, forum posts, or google hits on it folks might not be aware of it as an option.
So I guess the shorter response I could have given was "No, don't discard what you know but, if you have time, take a look at it and maybe add it to your tool belt if there's room".
With every tool I add to my belt, I find myself figuring out how to do things in better ways than I had before, even when using more familiar tools. Learning new things keeps you fresh
