I have a product.xhtml and a ProductBean. I use /product/{id} to access the products so I have a viewParam in product.xhtml with value=ProductBean.id. The problem is that inside the bean I use an init function with a PostConstruct annotation in order to fill the details of the product. To do this I need the id to call an external function. I guess though that init is called before viewParam sets the id of the bean and therefore inside init I cannot call the external function because id is not set yet. What am I doing wrong and how do I fix this?
UPDATE
I found what was wrong. I think the viewParam method works with CDI beans but the ManagedProperty method works with JSF beans..
I do have one other problem now. My CDI bean is RequestScoped and when the product.xhtml is rendered the bean is created and I guess is later discarded. The funny thing is that I have a function inside that bean which when I call, I can read the id (which I assume this happens because is connected to the view param) but not any other properties. Any ideas how to fix this?
You need a <f:event type="preRenderView"> instead.
<f:metadata>
<f:viewParam name="foo" value="#{bean.foo}" />
<f:event type="preRenderView" listener="#{bean.onload}" />
</f:metadata>
With
public void onload() {
// ...
}
Note that this is in essence a little hack. The upcoming JSF 2.2 will offer a new and more sensible tag for the sole purpose: the <f:viewAction>.
<f:metadata>
<f:viewParam name="foo" value="#{bean.foo}" />
<f:viewAction action="#{bean.onload}" />
</f:metadata>
See also:
ViewParam vs #ManagedProperty(value = "#{param.id}")
Communication in JSF 2.0 - Processing GET request parameters
Related
I've read how to send parameters using JSF but what if the user types their companyId in the URL when accessing their login page? For example,
http://my.company.url/productName/login.faces?companyId=acme.
The way we do it now, there is a bit of scriptlet code that grabs the value from the request and then set it in the session. That parameter changes their look and feel starting from the login page forward so each customer could have a different login page view. We are using extjs until I switch over to JSF.
Is there a way to do that using JSF 2 or perhaps PrimeFaces?
Yes, you can use the <f:viewParam> to set a request parameter as a managed bean property.
<f:metadata>
<f:viewParam name="companyId" value="#{bean.companyId}" />
</f:metadata>
You can if necessary invoke a bean action using <f:viewAction> (JSF 2.2+ only) or <f:event type="preRenderView">.
<f:metadata>
<f:viewParam name="companyId" value="#{bean.companyId}" />
<f:viewAction action="#{bean.onload}" />
</f:metadata>
When using <f:viewAction> you can even return a navigation outcome.
public String onload() {
// ...
return "somepage";
}
When not on JSF 2.2 yet, you can use ExternalContext#redirect() for that. See also among others How to perform navigation in preRenderView listener method.
Note that this is not specific to PrimeFaces. It's just part of standard JSF. PrimeFaces is merely a component library which provides enhanced ajax and skinnability support.
See also:
What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?
Communication in JSF 2.0 - Processing GET request parameters
#ManagedProperty with request parameter not set in a #Named bean
url paramters can also be treated as request parameters so you can also access through
FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap()
There is a utility library, OmniFaces which does this out of the box.
#Inject #Param
private String key;
#Inject #Param
private Long id;
You can use the request.getQueryString() if you want to get full query parameter string.
I'm trying to pass a parameter between a JSF page to another, from a bean to another. I know it is a common question, infact I've tried several approaches before writing it down.
To do that I have put both the beans in session scope and added in the first bean the following:
<p:commandButton value="Submit" type="submit"
actionListener="#{sourceBean.save}" action="success">
<f:setPropertyActionListener
target="#{targetBean.foo}" value="#{sourceBean.foo}" />
</p:commandButton>
The problem is that I don't want these beans to be in session scope but in view scope.
So I tried to put in my first page:
<p:commandButton value="Submit" type="submit"
actionListener="#{sourceBean.save}" action="success">
<f:param name="foo" value="#{sourceBean.foo}"/>
</p:commandButton>
And in the second page:
<f:metadata>
<f:viewParam id="foo" name="foo" value="#{targetBean.foo}"
/>
</f:metadata>
The problem is that the passed String is null so, obviously, I get an error form the Converter.
I think I'm missing something in the configuration of my managed beans. Do I have to link target and source bean in someway?
At this moment I have this configuration:
<managed-bean>
<managed-bean-name>targetBean</managed-bean-name>
<managed-bean-class>guiBeans.TargetBean</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
</managed-bean>
<managed-bean>
<managed-bean-name>sourceBean</managed-bean-name>
<managed-bean-class>guiBeans.SourceBean</managed-bean-class>
<managed-bean-scope>view</managed-bean-scope>
</managed-bean>
Another question: In my app, the value foo.id, that I use during the conversion, is set autonatically by the database when I save the object so when I call:
actionListener="#{sourceBean.save}"
The converter gets the id and turns it into a String (and viceversa, if needed).
So, I wanted to know if in JSF is first called the actionListener or the function that sets the parameters .
Could be this the reason why I get a null String? Thanks a lot.
The <f:param> is evaluated during rendering of the form, not during submitting of the form. Your problem suggests that the #{sourceBean.foo} value is only been set during submitting the form and thus not available during rendering of the form.
You'd basically need to replace action="success" by action="#{bean.action}" with
public String action() {
return "success?foo=" + foo.getId();
}
Or, if you're using navigation cases
<navigation-case>
<from-outcome>success</from-outcome>
<to-view-id>/some.xhtml</to-view-id>
<redirect>
<view-param>
<name>foo</name>
<value>#{sourceBean.foo.id}</value>
</view-param>
</redirect>
</navigation-case>
Unrelated to the concrete problem, the <f:param> doesn't support the converter attribute at all. You'd have to access the desired property directly (which is id in the above example).
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
I'm doing a page with jsf 2.0 and i wanna do something like this:
<f:metadata>
<f:viewParam name="id" value="${id}" />
<f:event type="preRenderView" listener="#{controller.initPage(id)}"/>
</f:metadata>
....(Some code)....
<c:forEach items="#{bean.listLoadedByInitPage}" var="var">
#{var.something}
</c:forEach>
The method initPage(id) must load list in the bean. But seems that method is called after than c:forEach loads items not before. Any ideas?
JSTL tags runs during view build time. The <f:event type="preRenderView"> runs right before view render time. In other words, <c:forEach> runs before <f:event>. So, this behaviour is fully expected.
You have 2 options:
Use #ManagedProperty instead of <f:viewParam>, or when the bean is in the view scope or broader, grab it manually from ExternalContext#getRequestParameterMap() inside #PostConstruct. And, use #PostConstruct instead of <f:event type="preRenderView">. Yes, this makes the entire <f:metadata> obsolete. You can safely remove it.
Use a JSF component instead of <c:forEach> tag, such as <ui:repeat>.
See also:
JSTL in JSF2 Facelets... makes sense?
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.