I need to cache #{request.contextPath} into a variable so that it could used multiple times within a page. Previously while I was working with Mojarra 2.1.3, I could use ui:param for this purpose & that would cache the expression value for entire page & across all the included pages in the current page. But it doesn't work with Myfaces(see issue) reason being <ui:param> should be direct child of <ui:include> or <ui:define> to work.
I have been suggested to use c:set but I want to avoid working with JSTL tags as far as possible. What is recommended for my use case ?
Just use <c:set>. It doesn't harm anything in this particular case.
but I want to avoid working with JSTL tags as far as possible.
It look like that you don't understand why and when JSTL tags should (not) be used and thus overgeneralizes the usage of all JSTL tags in JSF as "bad" for ever. You shouldn't think that. Carefully read this answer to get enlightened: JSTL in JSF2 Facelets... makes sense?
Related
in JSF we have the well-known problems that originate from the distinction between taghandlers and components, which manifest for example in the question why JSTL-tags in datatables do not work as expected.
My question is, is there an intrinsic reason why this distinction had to be made? Why cannot we have e.g. a datatable implemented as a taghandler so that every row exists as a component in the JSF-Tree?
I am just wondering why so many people have to fall into the pits created by this distinction.
My question is, is there an intrinsic reason why this distinction had to be made? Why cannot we have e.g. a datatable implemented as a taghandler so that every row exists as a component in the JSF-Tree?
Efficiency. Imagine that your table has 100 rows and that there are 10 column components which in turn have 2 child components. You'd bump from 30 components to 3000 components. Ugh. The server memory wouldn't be happy with it.
... which manifest for example in the question why JSTL-tags in datatables do not work as expected.
Just don't use JSTL tags if you rely on variables which are only available during view render time. Use the rendered attribute instead.
General advice for starters in JSF: do not use JSTL until you understand the distinction between view build time and view render time. Only when you understand it, you're going to highly appreciate the powers of JSTL. It will save you from among others programmatically creating components in beans.
See also:
JSTL in JSF2 Facelets... makes sense?
JSTL c:if doesn't work inside a JSF h:dataTable
i work on a project where we use JSF + Primefaces
I would like to know if it's preferable to use JSF components as much as possible even if there are sometimes the same components in Primefaces (for basic use)
Using Primefaces only for specific things not available on the JSF version
When should we use Primefaces instead of JSF ?
sorry for any faults
In general, I'd say prefer them than JSF standard components, the reason is simple: CSS skinning. For example, even if h:inputText and p:inputText are exactly the same component, you might want to have the same CSS skinning for all JSF components (specially if you use a premium layout from PF)
But, I think there are few exceptions:
If you use JSF 2.3. For example, I'd rather use h:commandScript than p:remoteCommand. As they're not "visual" components, I'd prefer to use standard components. See also what works better for you ;-)
Also, Oleg presents some performance killer using PF components in datatable, see here http://ovaraksin.blogspot.com/2013/05/jsf-choice-between-legacy-components.html
I think the most important point is consistency, which comes in a couple of flavours.
PrimeFaces (PF) components have a lot of styling put on them (through the theme options). If you use PF components throughout your application, you'll get a consistent style. If you mix PF and JSF components this will look messy.
PF components have a particular way of doing things - organising options, defining ajax calls etc. While it's important to know how the JSF stuff works underneath, using PF components consistently will make your code consistent too.
Finally, in many cases PF components are exact replacements for JSF components, but often with extra features added. There's no reason not to take advantage of them.
Better choose one of them and develop all application using mainly one stack. Will be easy to support, easy update, easy bug fix.
Primefaces at the moment good choose.
Is there any reason not to use c:if over the rendered attribute? When I started learning jsf the general vibe I got from the tutorials I read was that jstl tags should be forgotten. So everytime I use a jstl tag I feel like I'm doing something wrong.
However for c:if, it is executed at build time while rendered jsf attribute is executed at rendering time (explanation here). It looks like a waste to me to add something to the component tree if it's not to be rendered afterwards. Better not adding it at all using c:if, amiright?
For example on a all my pages, I've an admin menu that is included if the user is admin. I see no reason to add the menu to the tree if it's not to display it when page is rendered. So I just use c:if there. I use rendered on small parts when it's more convenient or for ajax type things.
I am trying to get the reusable group of jsf 1.2 components inside a panelgrid using Facelet tag file. #Balusc's previous answer at How to make a grid of JSF composite component? was a fabulous resource. I have a couple of followup questions:
In my c:when how do I test for the tagName itself instead of checking for the attributes. Instead of
<c:when test="#{type != 'submit'}">
I want to check tagName itself to decide how to format it. If 'input' do xxx.
2 Is this approach is still valid with jsf 1.2 other than f:ajax? If yes, can I replace with a4j:support...?
In my c:when how do I test for the tagName itself instead of checking for the attributes.
I'm not sure how this question makes sense. It sounds like that you're approaching something not entirely right. Do you maybe have copypasted exactly the same piece of code over multiple tag files? You should not do that. Make it a reuseable <ui:composition> or maybe <ui:decoration> instead which you compose/decorate in every tag file along with a fixed and unique <ui:param> value depending on the taglib file.
Is this approach is still valid with jsf 1.2 other than f:ajax? If yes, can I replace with a4j:support...?
Being able to create tag files is not necessarily specific to JSF, but to the view technology used, which is in this case Facelets. You can even do similar stuff in its predecesor JSP, see also this answer for an example: JSF 1.2 custom component from jsp:include It should work just fine in every JSF version supporting the view technology in question.
As to ajax support, it doesn't matter to the tag file what you're all doing inside the tag file. If you want and can use <a4j:support> then just do it.
I noticed that c:set does not work well used inside "include of include of include", as important notice facelets documentation does't recommend it too.
Now I am using ui:param inside ui:include, but it is a bit dispersive when no attached notes about params comes with the include, is there something other way to declare "global vars"?
This is really a matter of trying to fit old JSP programming into the JSF framework. You should be using backing beans to hold your data.
If you try to hard-code data directly into your xhtml file, you are defeating the purpose of JSF's MVC framework. If you have a specific example of what you are trying to do, I could give you a specific recommendation.