For page for print, which is text only, no command link/button to click, there is no need to save states for print pages. Is there a way to tell JSF not to save states? Thanks.
JSF already won't save state anyway if the view does not contain any <h:form>. So there's nothing to worry about.
The <f:view transient="true">, which enables stateless mode since Mojarra 2.1.19, would not have any additional advantage if the view already doesn't contain any <h:form>.
With newer versions of Mojarra you can do this:
<f:view transient="true">
Your page
</f:view>
But I don't think that doing this will have any significant positive effect on your application.
Related
I have a question about the idea behind the fact, that only UIForm got the attribute prependId. Why is the attribute not specified in the NamingContainer interface? You will now probably say that's because of backward compability but I would preferre breaking the compability and let users which implement that interface, also implement methods for the prependId thing.
The main problem from my perspective about the prependId in the UIForm component is, that it will break findComponent()
I would expect that if I use prependId, then the NamingContainer behaviour would change, not only related to rendering but also when wanting to search for components in the component tree.
Here a simple example:
<h:form id="test" prependId="false">
<h:panelGroup id="group"/>
</h:form>
Now when i want to get the panelGroup component I would expect to pass the string "group" to the method findComponent(), but it won't find anything, I have to use "test:group" instead.
The concrete problem with that is, when using ajax with prependId="false". The ajax tag expects in the attributes update and process, that the values care of naming containers. It's a bit strange that when I use prependId="false" that I have to specify the full id or path, but okay.
<h:form id="test" prependId="false">
<h:panelGroup id="group"/>
</h:form>
<h:form id="test1" prependId="false">
<h:commandButton value="go">
<f:ajax render="test:group"/>
</h:commandButton>
</h:form>
Well this code will render without problems but it won't update the panelGroup because it cannot find it. The PartialViewContext will contain only the id "group" as element of the renderIds. I don't know if this is expected, probably it is but I don't know the code. Now we come to the point where the method findComponent() can not find the component because the expression passed as parameter is "group" where the method would expect "test:group" to find the component.
One solution is to write your own findComponent() which is the way I chose to deal with this problem. In this method i handle a component which is a NamingContainer and has the property prependId set to false like a normal UIComponent. I will have to do that for every UIComponent which offers a prependId attribute and that is bad. Reflection will help to get around the static definition of types but it's still not a really clean solution.
The other way would be introducing the prependId attribute in the NamingContainer interface and change the behaviour of findComponent() to work like described above.
The last proposed solution would be changing the behaviour of the ajax tag to pass the whole id, but this would only solve the ajax issue and not the programmatic issues behind the findComponent() implementation.
What do you think about that and why the hell is it implemented like that? I can't be the first having this problem, but I wasn't able to find related topics?!
Indeed, UIComponent#findComponent() as done by <f:ajax render> fails when using <h:form prependId="false">. This problem is known and is a "Won't fix": JSF spec issue 573.
In my humble opinion, they should never have added the prependId attribute to the UIForm during the JSF 1.2 ages. It was merely done to keep j_security_check users happy who would like to use a JSF form with JSF input components for that (j_security_check requires exact input field names j_username and j_password which couldn't be modified by configuration). But they didn't exactly realize that during JSF 1.2 another improvement was introduced which enables you to just keep using <form> for that instead of sticking to <h:form>. And then CSS/jQuery purists start abusing prependId="false" to avoid escaping the separator character : in their poorly chosen CSS selectors.
Just don't use prependId="false", ever.
For j_security_check, just use <form> or the new Servlet 3.0 HttpServletRequest#login(). See also Performing user authentication in Java EE / JSF using j_security_check.
For CSS selectors, in case you absolutely need an ID selector (and thus not a more reusable class selector), simply wrap the component of interest in a plain HTML <div> or <span>.
See also:
How to select JSF components using jQuery?
How to use JSF generated HTML element ID with colon ":" in CSS selectors?
By default, JSF generates unusable ids, which are incompatible with css part of web standards
I need to complete a xhtml page with some JSF code (with p:panel and p:datatables, etc.) from a managed bean, but I'm not sure that is possible.
My attemps:
1º
<h:outputText escape="true" value="#{controller.jsfString}"/>
It's not be able to understand "p:" components, only simple html.
2º
<ui:include src="#{controller.jsfString}">
It expects a xhtml path, not a String.
I don't know what else try... Is it even possible?
It's not be able to understand "p:" components, only simple html.
Of course it is not!
The h:outputText value is evaluated at view render time, so if you render JSF tags, they won't be evaluated again since rendering is done.
In principle, it could have been possible to add JSF tags this way using the JSTL <c:out>, but it is not available in JSF facelets.
Anyway, just tell yourself that it prevents you from making bad design.
We'll need more information regarding what the controller is supposed to output in order to help you.
Here p means prime-faces u need to include prime-faces dependency in pom and enable tag lib for prime-faces in XHTML then u can use the all the prime-faces components.
I have a complex problem with order of 'JSF bean life cycle actions'.
I have two beans with different scopes. The first, let's call it, managerBean is session scope bean. The second one, someBean has view scope (someBean really is many different beans). ManagerBean takes some action once per page loading and few others view scope beans are using the results of this action in their constructors.
Everything was working just fine until I've started getting forms IDs in xhtml files from java beans. Now action from managerBean is taken after someBean is created and I'm getting expected result only when the page is reloaded (on refresh, so someBean is using the first results of ManagerBean work).
This is how it looks like now:
<!-- mainTemplate is a main templete of the page which is rendered once
per page view (every other actions are taken via ajax). This is a place
of ManagerBean work after re rendering the page -->
<ui:composition template="/mainTemplate.xhtml">
<ui:define name="mainContent">
<h:form id="#{someBean.formID}">
some inputs
</h:form>
(...)
</ui:define>
</ui:composition>
So when form id was constant String everything worked like I want and now it doesn't. It looks like JSF must calculate ID first and take any other after this (including ManagerBean action).
My question is: Is there a way to change this situation?
If something isn't clear enought, please ask. I was trying to simplify the problem because it has many factors. Maybe all my thinking is wrong (the way I want to take some action per page and some actions after it).
Any help will be good!
The id (and binding) attribute of a JSF UI component is evaluated during view build time. The view build time is that moment when the XHTML source code is turned into a JSF UI component tree. All other attributes of a JSF UI component like value and all events like preRenderView are evaluated/executed after the view build time, usually during view render time (when the JSF UI component tree needs to produce HTML output). This is not something which you can change by just turning a setting or so. It's just the way how JSF works. You can't render something which isn't built yet. You can only change this by writing code the right way.
I can't think of any real world scenario why you need to make the ID attribute dynamic like this. If it were inside a <c:forEach>, or part of dynamic component generation, then okay, but this seems just to be a static form. So I would in first place recommend to forget it and just hardcode the ID in the view and rely on other variables (perhaps a hidden input field? depends all on concrete functional requirement which isn't mentioned anywhere in the question nor guessable based on the code posted so far).
If you really need to make it dynamic, then you need to split the formID property off from the view scoped bean and move it to a different and independent bean, perhaps an application scoped one.
See also:
JSTL in JSF2 Facelets... makes sense? - component's id attribute has same lifecycle as JSTL tags
I'm facing the following exception in a very simple JSF 2 page after adding <h:form>:
java.lang.IllegalStateException: Cannot create a session after the response has been committed
at org.apache.catalina.connector.Request.doGetSession(Request.java:2758)
at org.apache.catalina.connector.Request.getSession(Request.java:2268)
I'm using Mojarra 2.1.3 and PrimeFaces3.0M4, on Tomcat 7.0.22 and JDK 7.
The page is a very basic data table:
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui">
<h:head>
</h:head>
<h:body>
<h:form>
<p:dataTable var="car" value="#{tableBean.cars}">
......
</p:dataTable>
</h:form>
</h:body>
</html>
The page shows correctly on the browser, but on the console I see the exception. The Exception does disappear if I remove the <h:form>.
How is this caused and how can I solve it?
This is a known problem and has been reported by yours truly as issue 2215. This will occur when the response buffer has overflowed (due to large content) and the response is been committed before the session is been created. This is result of bit overzealous attempts of Mojarra to postpone "unnecessary" session creation as much as possible (which is at its own a Good Thing though).
Until they get it fixed, there are several workarounds:
Create a Filter which does HttpServletRequest#getSession() before FilterChain#doFilter(). Advantage: no need to change JSF configuration/code. Disadvantage: when you want to avoid unnecessary session creation yourself as well.
Call ExternalContext#getSession() with true in bean's (post)constructor or preRenderView listener. Advantage: actually, nothing. Disadvantage: too hacky.
Add a context parameter with name of com.sun.faces.writeStateAtFormEnd and value of false to web.xml. Advantage: unnecessary session creation will be really avoided as opposed to #1 and #2. Disadvantage: response will now be fully buffered in memory until </h:form> is reached. If your forms are not extremely large, the impact should however be minimal. It would however still fail if your <h:form> starts relatively late in the view. This may be combined with #4.
Add a context parameter with name of javax.faces.FACELETS_BUFFER_SIZE and a value of the Facelets response buffer size in bytes (e.g. 65535 for 64KB) so that the entire HTML output or at least the <h:form> (see #3) fits in the response buffer. Advantage/disadvantage, see #3.
Add a context parameter with name of javax.faces.STATE_SAVING_METHOD and value of client to web.xml. Advantage: session will not be created at all unless you have session scoped beans. It also immediately solves potential ViewExpiredException cases. Disadvantage: increased network bandwidth usage. If you're using partial state saving, then the impact should however be minimal.
As to why the problem disappears when you remove <h:form>, this is because no session needs to be created in order to store the view state.
Update: this has as per the duplicate issue 2277 been fixed since Mojarra 2.1.8. So, you can also just upgrade to at least that version.
With the new version 2.1.21 released yesterday of javax.faces this problem seems to have disappeared.
Declare the new version:
<dependency>
<groupId>org.glassfish</groupId>
<artifactId>javax.faces</artifactId>
<version>2.1.21</version>
</dependency>
and replace the javax.faces.jar in the glassfish modules folder replacing the javax.faces.jar for the new version 2.1.21.
In my case (myfaces-2.2.8 & Tomcat 8.0.23) the Problem was a typo in the welcome-file of web.xml.
While debugging i saw, that Tomcat created as expected a 404, but somehow myfaces tried to access afterwards the Session, which caused then a java.lang.IllegalStateException: Cannot create a session after the response has been committed.
Using a valid page in welcome-file of web.xml fixed the Problem for me.
You may need to add an <f:view> and </f:view> before and after h:form elements, plus add the link to you html tag for jsf tags
<html xmlns:f="http://java.sun.com/jsf/core">
for this to work.
If you are using Spring MVC and call is made by Spring Forms then we should use GET method instead of POST(to fetch data) and there should be no input field we can use intead.
I am working on JSF. I have an xhtml page with multiple forms. when i am submitting one form, and if i had made some changes on other form i am loosing it, as on submit the page is getting refreshed. I cannot use a single form. is there any way to do.
any solution will be highly appreciated.
thanks !
If you're already using JSF 2.x (your statement that you're using XHTML (Facelets) confirms this less or more), just submit the form by ajax.
It's a matter of adding the following tag to the command links/buttons of the form:
<f:ajax execute="#form" render="#form" />
This way the current <h:form> will be submitted by ajax and the current <h:form> only will be rendered (updated/refreshed). You can if necessary specify other to-be-updated components in the render attribute by adding other client ID(s).
If you're still on the old JSF 1.x, you may want to look at Ajax4jsf sublibrary of RichFaces which supports basically the same.