I am reading through the Public Review Draft of the Web Beans specification (JSR-299) and I am wondering why it is so 'tightly coupled' to JSF?
Especially the Conversation Context seems only be specified for JSF.
I understand, that it is a goal of WebBeans to integrate JSF and EJB3. But would it not make sense to specify the concept of conversations on a more general level (maybe for Servlets in general and not for a specific web framework)?
Is there any technical reason for this? I think it can hardly be, because Seam (which is some Kind of WebBeans-Prototype) does also support Wicket and provides the concept of conversations.
I think it would be helpful to have a Conversation Scope on Servlet level (injecting of conversation-scoped beans into servlets). In my understanding, this is not the case with the ciurrent specification (see chapter 8.5.4). Or am I misinterpreting something here ...
Just found this today. The reason why the ConversationScope is JSF based is simply because JSF is the standard UI framework for Java EE!
Beside this, most of the JSR-299 containers can provide Conversations for other UI technologies like e.g. Wicket too.
Otoh you can easily create your own Scopes which are even portable.
LieGrue,
strub
I think it's soley down to Gavin King picking JSF as his view technology for Seam and him pushing through the JSR as spec lead.
Clearly conversations go wider - for instance, Spring custom scopes have a facility for providing conversations:
http://static.springframework.org/spring/docs/2.5.x/api/org/springframework/beans/factory/config/Scope.html
Related
From the wiki page about JSF I've learnt that it's considered as an MVP framework. But I cannot realy understand why.
Actully, beans do not contain a reference to View in themselves. There's also a data bidinig mechanism between Facelets and Managed beans.
So I would say that Managed Beans are more ViewModel than Presenter, as that Presenter usually contain a View interface in itself like in that example.
QUESTION: Why is JSF considered MVP but not MVVM framework?
MVVM is mainly a desktop application oriented pattern. When considering MVVM in web application perspective, there would be a controller in the client side. JSF doesn't have such one. When still speaking about web applications, if you were using e.g. Spring MVC in server side with e.g. AngularJS or Node.js in client side, you may speak about MVVM.
I am going through all the scopes in JSF2.0. I am a little confused about when to use custom Scope. Any specific use cases it will be useful.
Initially I thought I can use it for scope spanning multiple pages like three page registration etc. But looks like we cannot use it there.
Better late than never: I wrote an article about the usage custom scopes in JSF2 : JSF 2 Custom Scopes without 3rd party libraries
Well, the general idea is to create your own Scope for what ever you like e.g. kind of "Conversation Scope". The problem is already adressed within JSR 299 (CDI) and imho this is where it belongs to.
My attempts to create a custom scope resulted in Exceptions thrown by the JSF implementation as soon as the context is destroyed. Since it seems that there are no working examples available, custom scopes should be considered as non-existent in JSF2.0, though announced as a key feature.
Anyway, if you are looking for custom scopes take a look at CDI (escpecially Weld and MyFaces CODI), MyFaces Orchestra (for Conversation Scopes in JSF), Seam (offers a nice solution) or create a Custom Scope using Spring.
HTH
Just a general question, open for discussion...
I'm very much liking JSF so far, I'm new to it, but I prefer it to Struts. From a professionals standpoint, do you see a strong future for JSF ? Is it worth an investment as a young programmer to learn JSF 2.0 over Struts or another similar framework ? Should I stick to regular JSP ? Is Ajax really simpler through JQuery than JSF ?
I like new technologies and I like what I see so far from JSF but I want to be practical as well, and a lot Google searches turn up some bluntly critical comments about JSF 2.0.
Thoughts ?
Comparing JSF with Struts is like comparing apples with oranges. Struts is a request/action based MVC framework while JSF is a component based MVC framework. Struts is also aged. In the IT you're supposed to keep moving. Generally, a component based MVC framework is seen as a further evolution of a request/action based MVC framework.
JSF is currently already used very widely. It has indeed received a lot of critism before. You can read about most of them in the question What are the main disadvantages of JSF 2.0? The strength of JSF is mainly being a Java EE maintained standard and the availability of relatively a lot of 3rd party component libraries (PrimeFaces, RichFaces, IceFaces, OpenFaces, Tomahawk, etc). With JSF, it's very easy to develop CRUD applications and web forms with nice look'n'feel quickly.
However when it goes into the complex, JSF may cause some unforeseen surprises. Although the JSF specification and reference implementation (Mojarra) is pretty mature since the latest 1.2 builds, you may encounter some very specific behavioral problems which goes against your intuition. Some are just "by design" and can only be understood when you understand in detail how JSF works under the covers which in turn often boils down to the stateless nature of the HTTP protocol. JSF abstracts it in essence "too much" away that you don't see it anymore. Some are just bugs in the 3rd party component libraries used, but that's thus not strictly JSF-implementation-specific. Bug/issue handling is however pretty good in most of the major component libraries -if you report the bugs timely.
As to ajaxical stuff, JSF 2.0 indeed provides very little manual control over manually firing ajaxical requests and controlling the view tree in both server and client side. Simply because it's a component based MVC framework which keeps the tree state at the both sides. You've got to take the both sides into account when taking the ajaxical works in your own hands. If you really need more freedom in ajax/request based actions, then a component based MVC framework is simply the wrong choice. You should pick a request/action based MVC framework instead like Spring MVC, Struts or Stripes, along with a JS library like jQuery. You however have to write lot of HTML/CSS/JS boilerplate yourself instead.
I am begining a web system and can't decide what technology use! Struts2 and JSF (with jboss seam) are a nice choices, but I can't decide which's better. In JSF have some that I don't like, maybe its "paradigm" no action like. And Struts2, the peoples here don't use more.
The system is a map collaborative web site.
I have used both Struts2 and JSF extensively, both are good but I would still recommend JSF. Here is why.
More users. Yes this counts; more people means its easier to get hands on new programmers.
Better tool support. IDEs like IntelliJ have very good JSF support.
Facelets. Lets face it, JSP sucks. You simply should not be allowed to write business logic inside your view code. Keeping your views in XHTML ensures that they are clean and tidy.
Documentation/Books. This might have changed, but when I was in the struts2 camp (2007/2008) the books available was few and of very poor quality. There is a good choice of JSF/Seam books.
JSF2/Seam. JSF2 is very nice (and IntelliJ 9 supports it). New scopes, such as the view scope, are really helpful (fx. if you are having a long running conversation in a flow).
If you are interested in some of the newer features in JSF2 then checkout this blog post. Also you might want to check out Stripes, it is also a very nice server side web framework and finally here is a very thorough (and a little old) comparison of most Java web frameworks.
This a very debatable topic. I think the main advantage of Struts2, compared to JSF, is its simplicity, it is much easier to grasp. Specially for beginners in web programming, or those familiar with "action based" web frameworks (Struts 1, Webworks, Spring MVC, Stripes).
But Lars Tackmann's points are valid (though Struts2 does not force you to use JSP; and indeed it uses FreeMarker internally). It's true that Struts2 has not attained a big user base, the community (both users and developers) does not seem to be very active, and that is a big minus. JSF also has its shortcomings, I've heard (I've not used it)... as every Java web framework, it seems.
What do people think is the best JSF framework or library for a saving state longer than request scope (but w/o using session scope) that is backbutton/new window safe -- i.e. you have a "wizard"/multi-page form.
For example, MyFaces has the 'SaveState' tag that allows you to maintain state across pages by saving state in the view's component tree. Any comments on SaveState (pros/cons) or suggestions for any better framework or library for this capability?
The t:saveState works perfectly. It's only a bit 'low level' and not tied to a particular bean. There are two other libraries/frameworks which comes to mind which provides control over conversation scope at higher level (e.g. bean-specific tags/annotations):
Apache MyFaces Orchestra (uses tags)
JBoss Seam (uses annotations)
Update: JSF2.0 has added a new scope which achieves a conversation-like state, the #ViewScope. Very useful if you can reuse the same view for subsequent actions.
i think Spring Web Flow is a good solution. you can define your flow as XML and it can integrate with JSF, Struts, Spring MVC, ZK,...
http://www.springsource.org/webflow