I'm trying to pass an object to another site. So i have my Gallery.xhtml where I set an object as current and redirect to another page:
<h:form>
<a4j:commandButton value="Edit Skin"
action="#{helloBean.setCurrentSkin(skin)}"
onclick="window.location.href = 'resources/html/Editor.xhtml';" />
</h:form>
But when the getter on the second page is called, the current object is null again.
Is the bean generated for each page? How could I achieve this?
My Problem was that I declared my bean as #ViewScoped, but the proper Tag is #SessionScoped. This makes sure that the Bean holds its values for the whole session and not only one view.
Related
I'm trying to use the setPropertyActionListener tag to set a value in my backing bean. However, it doesn't work as I expected.
Context: userService is an instance of my backing bean, which contains an int member, reqID. This, in turn, is the key to a map of objects that belong to a class called User. I'm trying to create a page that will list all instances of User, and provide a button to visit a separate view that shows that particular User's information. To do this, I'm attempting to set userService.reqID to the id of the chosen User so it can generate a reference to that user for the next view (which is done in the call userService.toUserInfo).
If I use the xhtml snippet below:
<ui:define name="content">
<h:form>
<h:panelGrid>
<ui:repeat value="#{userService.UserList.getUserList()}" var="user">
<li>
<h:outputText value="#{user.name}" />
<h:commandButton value="View details of #{user.name}" action="#{userService.toUserInfo}">
<f:param name="id" value="#{user.id}" />
<f:setPropertyActionListener target="#{userService.reqID}" value="#{id}"/>
</h:commandButton>
</li>
</ui:repeat>
</h:panelGrid>
</h:form>
</ui:define>
The tag does not appear to evaluate id correctly and I get a Null Pointer Exception.
Earlier, I tried changing my setPropertyActionListenerTag so it read out as:
<f:setPropertyActionListener target="#{userService.reqID}" value="id"/>
which gave me an error, because the tag was sending the string "id" as opposed to the int value of the parameter.
Is there some way to force f:setPropertyActionListener to evaluate the expression under value? Or is there another tag that will allow me to do this?
Also, is ui:param used appropriately here?
The <f:param> (and <ui:param>) doesn't work that way. The <f:param> is intented to add HTTP request parameters to outcome of <h:xxxLink> and <h:xxxButton> components, and to parameterize the message format in <h:outputFormat>. The <ui:param> is intented to pass Facelet context parameters to <ui:include>, <ui:decorate> and <ui:define>. Mojarra had the bug that it also behaves like <c:set> without a scope. This is not the intented usage.
Just use <c:set> without a scope if it's absolutely necessary to "alias" a (long) EL expression.
<c:set var="id" value="#{user.id}" />
Put it outside the <h:commandLink> though. Also in this construct, it's kind of weird. It doesn't make the code better. I'd just leave out it.
<f:setPropertyActionListener ... value="#{user.id}" />
See also:
Setting ui:param conditionally
what is the scope of <ui:param> in JSF?
Defining and reusing an EL variable in JSF page
Unrelated to the concrete problem, if you're using EL 2.2 (as you're using JSF 2.2, you undoubtedly are as it requires a minimum of Servlet 3.0, which goes hand in hand with EL 2.2), then just pass it as bean action method argument without <f:setPropertyActionListener> mess. See also a.o. Invoke direct methods or methods with arguments / variables / parameters in EL and How can I pass selected row to commandLink inside dataTable?
<h:commandButton ... action="#{userService.toUserInfo(user.id)}">
On again another unrelated note, such a "View user" or "Edit user" request is usually idempotent. You'd better use <h:link> (yes, with <f:param>) for this. See also a.o. Creating master-detail pages for entities, how to link them and which bean scope to choose and How to navigate in JSF? How to make URL reflect current page (and not previous one).
Oh, that <h:panelGrid> around the <ui:repeat><li> doesn't make sense in HTML perspective. Get rid of it and use <ul> instead. See also HTMLDog HTML Beginner tutorial.
I have a ViewScoped Managed Bean. In my .xhtml page I want to set bean's attribute's value and use it in methods in the same bean.
I managed to set the value from jsf page, but when i want to use it in some method the value of an attribute is not the value i have set before.
Description (xhtml):
In this form there is a command link which sets the value of an attribute. And it is working fine. Also, as command link is clicked, second form is being showed.
<h:form>
<h:commandLink value="Set" >
<f:setPropertyActionListener target="#{bean.attribute}" value="true" />
<f:ajax execute="#this" />
</h:commandLink>
</h:form>
This form executes method that uses attribute's value set before, but the value is not true, its false.
<h:form>
<h:commandButton id="submit" value="Execute" action="#{bean.execute}" />
</h:form>
Bean:
public void execute(){
if(isAttribute())
---do something---
}
The question is: Why execute() is not reading attribute's value right?
When I use one form, it's working fine. But I need them to be in separated forms.
The scope of your bean is incorrect. ViewScoped means that the minute the view is changed, the bean is discarded and re-created for the next view. So, in your case, the original data you had for the first view is lost.
I'm going to refer you to BalusC's blog:
http://balusc.blogspot.co.uk/2010/06/benefits-and-pitfalls-of-viewscoped.html
which states:
A #ViewScoped bean will live as long as you're submitting the form to the same view again and again. In other words, as long as when the action method(s) returns null or even void, the bean will be there in the next request. Once you navigate to a different view, then the bean will be trashed
I can't determine of you stay on the same page with both requests. If you do, viewScope should work even in two different forms. If you are navigating from 1 view to another, another viewScope will be created and you will loose the current one.
You could set the value in the sessionScope with java or by annotating the backingNean. But then everything in your backingBean becomes sessionScoped and that might not be needed.
You could also use a spring-like flow scope.
Example to do it with java:
public void callThisAfterFirstClick() {
Faces.setSessionAttribute(attribute, true)
}
public void callThisAfterSecondClick() {
Faces.getSessionAttribute(attribute);
}
I am a JSF beginner. I have a question about managed bean.
Step 0:
There is a managed bean BeanA, scope is request. And BeanA instance1.propertyA = "0";
Step 1:
using ajax to change country, then in BeanA.countryChanged method, change managed bean BeanA.propertyA = "A".
<t:selectOneMenu id="Country" required="true" valueChangeListener="#{BeanA.countryChanged}">
<a4j:support event="onchange" limitToList="true" ajaxSingle="true" />
<f:selectItems value="#{BeanA.countries}" />
</t:selectOneMenu>
Step2:
submit form to do validate a text input
<h:inputText id="street" required="#{BeanA.propertyA == "A"}"
I expect that in step2 the value propertyA of BeanA instance2 should be "A" in JSF validate phase, but actually it is "0". I don't know how does JSF load BeanA instance property values to create new BeanA instance. And what should I do, the value will changed to "A"? Thanks,
The symptoms indicate that your bean is request scoped. This means that it's reconstructed on every single HTTP request. You probably didn't realize that every single ajax request also counts as a separate HTTP request. In effects, you're not reusing the same bean instance across ajax postbacks on the same view. Every time a brand new instance is been created, with all its properties set to default.
JSF 2.0, which is designed with ajax in mind, has solved it with the new view scope in the standard API.
In JSF 1.x, you need to fall back to 3rd party component libraries. In your particular case, given that you're using both Tomahawk and Ajax4jsf, you've 2 options:
Use <t:saveState>.
<t:saveState value="#{BeanA}" />
Or, use <a4j:keepAlive>.
<a4j:keepAlive beanName="BeanA" />
I have a problem that i don't understand:
I request a new site. A site has a link that opens a dialog. The link is inside a form.
The dialog is not inside the form.
A reduced code example:
<p:outputPanel id="layout-center" >
<h:form>
<p:commandLink id="option_field_user_profile" actionListener="#{controllerBean.getBean('userProfileBean', component).init}" oncomplete="#{controllerBean.getBean('userProfileBean', component).show}" >
<h:outputText value="#{msg.mProfile}"/>
</p:commandLink>
</h:form>
</p:outputPanel>
<p:dialog header="#{userPreferencesBean.header}" widgetVar="#{userPreferencesBean.widgetVar}" appendToBody="#{userPreferencesBean.appendToBody}" resizable="#{userPreferencesBean.resizable}" id="#{userPreferencesBean.xhtmlId}" dynamic="#{userPreferencesBean.dynamic}" modal="#{userPreferencesBean.modal}" closable="#{userPreferenceBean.closable}">
<ui:include src="/WEB-INF/templates/modification/userPreferences.xhtml" />
</p:dialog>
UserPreferencesBean is in ViewScope. My problem is now that the #PostConstruct method from the UserPreferencesBean is called twice with the non-postback request i.e. the Bean is constructed twice although it should be the same view. If i move the dialog inside the form for testing purposes it is called once, like expected. But since the dialog has its own form this is not a solution, for sure.
When the site is loaded and I hit F5, the PostConstruct method is executed once.
Has somebody an idea?
This is caused because you referenced a view scoped bean property in the view build time attribute id of the <p:dialog>. If you fix the id to be static, or to reference a request or application scoped bean property instead, then your view scoped bean will behave as expected.
See also:
JSTL in JSF2 Facelets... makes sense? - for some background explanation on view build time and view render time; the id and binding attributes of UI components are evaluated during view build time.
My view is:
<h:commandLink value="BookFlight" action="#{bookSeatController.doLoginOrCC}">
<f:setPropertyActionListener target="#{bookSeatController.flightNumber}"
value="#{flightInfoController.flight.number}" />
</h:commandLink>
My setter is:
public void setFlightNumber(String flightNumber) {
this.flightNumber = flightNumber;
}
When I use the debugger I get a flightNumber of null in the setter. However, if I change the view to the following:
<h:commandLink value="BookFlight" action="#{bookSeatController.doLoginOrCC}">
<f:setPropertyActionListener target="#{bookSeatController.flightNumber}"
value="122334" />
</h:commandLink>
The flightNumber property is set to 122334. How is this caused and how can I solve it to set the intended value instead of null?
If the #{flightInfoController.flight.number} is request scoped, then it has to preserve exactly the same flight in during the request of processing the form submit as it was during the request of displaying the form. This has to happen in the bean's (post)constructor.
If that is not an option, because it depends on some request based variables, then your best bet is to put the bean in the view scope instead (I however still assume that your bean is properly designed that it doesn't do any business/preloading job in getters).
If putting the bean in the view scope is in turn not an option, then you'd need to pass it as a fullworthy request parameter instead. You can do that by <f:param>.
<h:commandLink value="BookFlight" action="#{bookSeatController.doLoginOrCC}">
<f:param name="flightNumber" value="#{flightInfoController.flight.number}" />
</h:commandLink>
You can let JSF set it by #ManagedProperty in the BookSeatController or by <f:viewParam> in the current view.
See also:
How can I pass selected row to commandLink inside dataTable?
ViewParam vs #ManagedProperty(value = "#{param.id}")
If it's working when assigning "122334" but when assigning flightInfoController.flight.number it's "null" and since you are not receiving any exception, then it means probably your flightInfoController is not properly initialized (regarding it's field flight and hence number in the flight).
Just make sure the bean is properly initialized (or update your OP with the bean code).