I can't inject a ConversationScoped bean into a ViewScoped bean, because the ConversationScoped bean could be shorter lived than the ViewScoped one, or vice versa, depending on whether or not the ConversationScoped bean is long-lived.
To get over this limitation, I tried using an f:event to perform the injection as a preRenderView listener:
<f:metadata>
<f:event type="preRenderView" listener="#{taskController.initializeTask(workPackageConversation.workPackage)}" />
</f:metadata>
This howver is not working, neither the listener initializeTask, nor the getter getWorkPackage are being called.
I realize I can lookup one managed bean from another, using the FacesContext, but I am curious why this isn't working. Is it because the f:event listener isn't called when I navigate to a view from another view? ie. without a redirect or direct page view?
I also tried the s:viewAction tag from Seam 3 Faces, to no avail. It does not get called either.
Thanks in advance.
I would think the lifetime issues would not come into play since you've always got a proxy to the normal-scoped bean anyway. You either dereference the conversation-scoped bean while the conversation is active, or it's not active -- but you'll always get the right conversation.
Related
I have a #viewScoped bean( say bean1) having an inputText as property .From the facelet, Iam setting the value of this inputtext field. However after the submit operation when the other facelet (whose managed bean say bean2 is in #viewScoped ) as well is loaded ,I need to retrieve the bean1 inputText values but iam not able to retrieve .I know in viewscoped bean the state is lost once we move to next view but is there a way to retrieve the values ? because i need to show the values in the next facelet ... By the way Iam using ajax so the bean has to be viewscoped
I even tried the following code in bean2 (#viewScoped) .but the sysout shown below is always null
#ManagedProperty(value="#{bean1}")
private Bean1 bean1;
System.out.println(bean1.getinputtext());
both the beans have to be in #viewScoped .Is there a way I can retrieve the values from bean 1 to bean 2 ? Thanks in advance
You can't access first view scoped bean any more. You can add your data to session, read that data from second bean and remove the data.
Is there a way to display a specific JSF page based on the request URL?
Let's say I have a JSF page "details.xhtml". The managed bean "detailsBean" has a list of objects where each object has its own ID. Now if a user requests the page "../details.xhtml?id=1", the list should be queried for an object with ID 1 and the resulting details page of this object should be displayed.
I already wrote a converter implementation class which can convert from object to ID and vice versa, but I don't know how to use it properly. Do I have to work through the JAX-RS specification for this to work or is there a more simple solution?
In JSF you can do this by using a so-called view parameter. You declare these in the metadata section of your Facelet:
<f:metadata>
<f:viewParam name="id" value="#{yourBean.yourObject}" label="id"
converter="yourObjectConverter"
/>
</f:metadata>
This will grab the URL parameter id from the request URL. E.g. if you request the page this appears on with localhost:8080/mypage.jsf?id=1, then 1 will be handed to the yourObjectConverter and whatever this converter returns will be set in yourBean.yourObject.
Your backing bean will thus get the converted object. No need to pollute your backing bean over and over again with the same query code.
#ManagedBean
public class YourBean {
private SomeObject someObject;
public void setYourObject(SomeObject someObject) {
this.someObject = someObject;
}
}
If your backing bean is view scoped, you may want to use the OmniFaces variant of viewParam instead, since otherwise it will needlessly convert after each postback (if your converter does a DB query, you definitely don't want this).
Working full examples:
http://code.google.com/p/javaee6-crud-example/source/browse/WebContent/user_edit.xhtml
http://code.google.com/p/javaee6-crud-example/source/browse/src/backing/UserEdit.java
Further reading:
Communication in JSF 2.0 - Processing GET request parameters
Stateless vs Stateful JSF view parameters
You can achieve this with plain JSF with the following steps
Capture the ID in the request to determine what object is being queried for in your DetailsBean from the request parameter. There are many ways to achieve this, one of which is adding the following annotation to your managed bean (this is currently only permitted for a #RequestScoped bean, see why here).
#ManagedProperty(value="#{param.id}")
int requiredObjectId;
The annotation above will capture the id parameter from the request and assign it to the requiredObjectId variable.
Using the captured Id, setup your object in your bean in a #PostConstruct method
#PostConstruct
public void queryForObject(){
//use the requiredObjectId variable to query and setup the object in the backing bean
}
The object retrieved should be assigned as an instance variable of your managed bean
In your view, you could then reference the queried object that has been setup in the backing bean
<h:panelGrid columns="2">
<h:outputText value="Title"/>
<h:outputText value="#{detailsBean.selectedObject.title}"/>
</h:panelGrid>
If your bean is in a scope broader than the request scope, you'll need a combination of constructs to cleanly pull that request parameter before view rendering.
Capture the request parameter within the JSF view itself using
<f:metadata>
<f:viewParam name="id" value="#{detailsBean.requiredObjectId}" required="true" requiredMessage="You must provide an Object Id"/>
</f:metadata>
**OR**
Due to the nature of JSF Lifecycle processing, doing the above alone may not make the value available for your use in time for object setup. You could use the following instead.
<f:metadata>
<f:event type="preRenderView" listener="#{detailsBean.setObjectId}" />
</f:metadata>
What we've done here is specify a method (that captures the id) in the backing bean that must be executed before the view is rendered, ensuring that the id parameter is available as at the time you need it. Proceed with step 3, only if you're using <f:event/> above.
In the backing bean, you now define the setObjectId method
public void setObjectId(){
Map<String,String> requestParams = FacesContext.getExternalContext().getRequestParameterMap();
requiredObjectId = Integer.parseInt(requestParams.get("id"));
}
Note that the above option is generally a work around/hack and not a clean solution as such
Please note: This question is about CDI scopes as we are using CDI scopes in the app and not JSF scopes.
1) Controller Bean (TestController.java) which is in RequestScoped (enterprise context) is called index_cut.xhtml, when we come for first time on this page.
2) On button “Load”, we load the following method to populate the sapFinancialPeriodList which works fine and displays the data
3) After changing the content on the page and submitting, the sapFinancialPeriodList appears as NULL in the following method –
Any suggestions?
Your bean is request scoped and you're loading the data model on action only instead of on (post)construction. When the HTTP response after the action which loaded the data is finished, then the bean is garbaged. The subsequent request would get a brand new instance of the bean with all properties set to default. However, as the same data model isn't been preserved during (post)construct, it remains empty.
In JSF2 you'd solve this with using #ViewScoped. This way the bean will live as long as you're interacting with the same view by postbacks (which return null or void).
In CDI you'd need to solve this using #ConversationScoped, which in turn requires some additional #Inject Conversation boilerplate, complete with begin() and end() calls at the right moments. For a concrete example, see also What scope to use in JSF 2.0 for Wizard pattern?.
An alternative is to pass the parameters responsible for creating the data model to the subsequent request via <f:param> in the command link/button as follows
<h:commandButton value="save" ...>
<f:param name="period" value="#{bean.period}" />
</h:commandButton>
and then recreate exactly the same data model in (post)constructor of the request scoped bean as follows
String period = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("period");
List<SapFinancialPeriod> sapFinancialPeriodList = someservice.list(period);
(the above is by the way nicer to solve with #ManagedProperty if you were using standard JSF; as far as I know CDI doesn't have an annotation which enables you to set a HTTP request parameter as a bean property)
See also:
How to choose the right bean scope?
Unrelated to the concrete problem, the upcoming JSF 2.2 solves this functional requirement in a nicer way using the new "Faces Flow" feature with the new #FlowScoped annotation and the new xmlns:j="http://java.sun.com/jsf/flow" tags.
I have a table of Items, and in each row there is a link that forwards to the edit item page. To load data in the edit page I need the managed bean in request scope (if I put it in view scope I loose data in the forward).
To use ajax in the edit page I need the managed bean in view Scope due to some values I must keep. If I were working with JSF 1.0 and RichFaces I would do it with request scope and a4j:keepalive.
How do I get this funcionality with PrimeFaces and JSF 2.0 or how can I redefine the interface to get this?
Ok, finally based on the post below this is what worked for me:
CommandButton in the Items table:
<o:commandButton id="editButton"
action="#{itemTableMB.editItem(item.id)}" styleClass="botonTabla">
<h:graphicImage styleClass="imagenBotonTabla" url="/resources/images/icons/pencil.png"/>
</o:commandButton>
Action in the managed bean:
public String editItem(Integer id){
return "/pages/items/edit.xhtml?faces-redirect=true&id="+id;
}
edit.xhtml:
<f:metadata>
<f:viewParam id="id" name="id" value="#{itemMB.item.id}" required="true">
</f:viewParam>
<f:event type="preRenderView" listener="#{itemMB.loadItem}" />
</f:metadata>
Listener in itemMB:
public void loadItem(){
this.item = this.itemManager.get(this.item.getId());
}
To load data in the edit page I need the managed bean in Request scope (If I put it in view scope I loose data in the forward).
Are you using a navigation rule (or implicit navigation) without a redirect?
One solution would be to put backing beans of both the "table of items"-page and the "edit item"-page in view scope, and then go from the first to the second one directly via a GET request (e.g. using <h:link>) or a POST/redirect with a request parameter representing the row on which the user clicked.
Use <f:viewParam> on the second page to conveniently convert the request parameter back to an entity representing the item being edited.
If you were indeed using navigation without redirect, then this has the additional benefit that you won't suffer from the notorious 'one-URL-behind-problem', which can be rather confusing to users of your application and be a nightmare for support.
As title.
The problem is the attribute in the bean is fixed after init().
I want to update the count attribute when ever i access #{managedBean.xyz} method in JSF
I want to stick with the sessionscoped instead of view/request because it saves some time for the Object re-creation.
I don't want to do the attribute update manually in every xyz function. thanks
If I understand you correctly, you want to invoke a bean method on every view which involves the bean?
Add <f:event type="preRenderView"> to those views.
<f:event type="preRenderView" listener="#{managedBean.countUp}" />
with
public void countUp() {
count++;
}
It will be invoked only once on every request.