In the top answer to this question for example : Java EE 6 #javax.annotation.ManagedBean vs. #javax.inject.Named vs. #javax.faces.ManagedBean I read that:
To deploy CDI beans, you must place a file called beans.xml in a
META-INF folder on the classpath. Once you do this, then every bean in
the package becomes a CDI bean.
And also it is said that:
If you want to use the CDI bean from a JSF page, you can give it a
name using the javax.inject.Named annotation.
I have a sample code that goes like this:
#ManagedBean
#ViewScoped
public class SignUpPage {
private User user;
#PostConstruct
public void init() {
user = new User();
}
#Inject
private UserDao userDao;
// rest of the class
So as far as I understand, my bean is still a JSF Managed Bean, it is not a CDI bean(or is it?). By the way, I have a beans.xml in my WEB-INF folder.
And #Inject works just fine in here. Also, I can access the bean with EL just fine(which makes me think it is still a JSF Managed Bean)
The UserDao class looks something like this:
#Stateless
public class UserDao {
EntityManager em;
#PostConstruct
public void initialize(){
EntityManagerFactory emf = Persistence.createEntityManagerFactory("Persistence");
em = emf.createEntityManager();
}
So, it is as far as I know an EJB..
So do I have any CDI beans in this example? How does #Inject work here?
Hope my question is clear, Regards!
By CDI specification, every JavaBean is a Managed Bean (do not confuse it with JSF #ManagedBean, this is a different one) in project where the beans.xml is present. So every class is also eligible for dependency injection. Note that default scope of this class is Dependent.
Related
I have a session scoped bean for a UI to edit some data. It is annotated with #Named and #SessionScoped and all runs in JBoss 6.2. Now I got the requirement for a nearly similar edit UI. The problem is that the two UIs can exist in parallel. So for a perfect reuse it would be nice to create a new instance of the bean with another name. Unfortunately I have no clue how to do this in a clean CDI way.
I don't like it so much to inherit from the bean and give another name. This was one of my ideas.
Another idea was to implement in the managed bean only the business logic and keep the data encapsulated from them and set the data object inside the managed bean when it is needed in the specific context. But maybe there is another CDI way with producers or something?
Changing the scope of the bean to ViewScope makes no sense in my case.
Thanks
Oliver
But maybe there is another CDI way with producers or something
Indeed, you could use a producer.
Kickoff example:
#SessionScoped
public class SessionBean {
#Produces
#Named("foo")
#SessionScoped
public SessionBean getAsFoo() {
return new SessionBean();
}
#Produces
#Named("bar")
#SessionScoped
public SessionBean getAsBar() {
return new SessionBean();
}
// ...
}
(method names are free to your choice)
Usage:
#Inject
#Named("foo")
private SessionBean foo;
#Inject
#Named("bar")
private SessionBean bar;
How can I access messages bundle from java code to get message according to current locale?
I tried using #ManagedProperty like below:
#Named
#SessionScoped
public class UserBean implements Serializable {
#ManagedProperty("#{msg}")
private ResourceBundle bundle;
// ...
public void setBundle(ResourceBundle bundle) {
this.bundle = bundle;
}
}
However, it remains null. It seems that it doesn't work inside a #Named.
This is how I registered the resource bundle in faces-context.xml:
<application>
<message-bundle>validator.messages</message-bundle>
<locale-config>
<supported-locale>en_US</supported-locale>
<supported-locale>ua_UA</supported-locale>
</locale-config>
<resource-bundle>
<base-name>lang.messages</base-name>
<var>msg</var>
</resource-bundle>
</application>
updated by author:
I get error
16:29:10,968 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/WEBSearchPrime_JB_lang].[Faces Servlet]] (http-localhost-127.0.0.1-8080-1) Servlet.service() for servlet Faces Servlet threw exception: org.jboss.weld.exceptions.IllegalProductException: WELD-000054 Producers cannot produce non-serializable instances for injection into non-transient fields of passivating beans\\n\\nProducer\: Producer Method [PropertyResourceBundle] with qualifiers [#Any #Default] declared as [[method] #Produces public util.BundleProducer.getBundle()]\\nInjection Point\: [field] #Inject private model.UserBean.bundle
note, that I also put Serializable interface
You can't use #javax.faces.bean.ManagedProperty in a CDI managed bean as annotated with #Named. You can only use it in a JSF managed bean as annotated with #ManagedBean.
You need use #javax.faces.annotation.ManagedProperty instead, along with an #Inject. This was introduced in JSF 2.3.
#Inject #javax.faces.annotation.ManagedProperty("#{msg}")
private ResourceBundle bundle;
Noted should be that this gets injected as a #Dependent. So be aware that when you inject this into a #SessionScoped bean, then it would basically become #SessionScoped too and thus stick to the originally injected value forever. So any potential locale changes later on in the session won't be reflected there. If this is a blocker, then you should really inject it into a #RequestScoped or #ViewScoped only, or make use of a #Producer as shown below.
CDI doesn't have native annotations to inject the evaluation result of an EL expression. The CDI approach is using a "CDI producer" with #Produces wherein you return the concrete type, which is PropertyResourceBundle in case of .properties file based resource bundles.
So, if you cannot upgrade to JSF 2.3, then just drop this class somewhere in your WAR:
#RequestScoped
public class BundleProducer {
#Produces
public PropertyResourceBundle getBundle() {
FacesContext context = FacesContext.getCurrentInstance();
return context.getApplication().evaluateExpressionGet(context, "#{msg}", PropertyResourceBundle.class);
}
}
With this, can inject it as below:
#Inject
private PropertyResourceBundle bundle;
In addition to BalusC's answer:
Since JSF 2.3 it is also possible to inject a resource bundle defined in faces-config.xml without the use of a producer method. There is a new annotation javax.faces.annotation.ManagedProperty (note it is in the ...annotation package, not the ...bean package) that works with #Inject:
// ...
import javax.faces.annotation.ManagedProperty;
// ...
#Named
#SessionScoped
public class UserBean implements Serializable {
// ...
#Inject
#ManagedProperty("#{msg}")
private ResourceBundle bundle;
// ...
}
Perhaps I'm getting something wrong, but actually neither of the solutions provided worked for my use case. So I'm providing another answer that worked for me.
With the answer provided by BalusC I encountered the following problems:
As I'm using ajaxbased validation, my beans are #ViewScoped, and
must be serializable. As neither ResourceBundle nor
PropertyResourceBundle are serializable they can't be injected with
#Dependent scope.
If I try to change the producer to use #RequestScoped it also fails
because ResourceBundle is not proxyable as it defines final
methods.
As I'm using JSF 2.3 (JBoss 7.2EAP) I went with the solution provided by Jören Haag and initially it seemed to work. Like the original question, I also have multiple supported locales, and the user can change between locales (in my case ca and es)
The problems I faced with Jören answer are
The ResourceBundle returned is evaluated when the bean is created. In his example he is using a #SessionScoped bean. The ResourceBundle will be resolved with the current locale when the session is created. If the user later changes the locale, the ResourceBundle will not get updated. This also happens with #ViewScoped beans if the user can change the language without changing the view.
I also encountered another issue with beans that need to preload data with a <f:viewAction>. In this case, the bean is instantiated earlier, so the ResourceBundle gets injected before the user locale is set with <f:view locale="#{sessionBean.locale}">. So If the user browser is using es, but the user changed the locale to ca, the bundle will be loaded with es instead, because the view locale is not set to ca with the sessionBean.locale until the render phase.
To overcome this issues that's the solution that worked for me for the use case of the question using injection would be:
#SessionScoped
public class UserBean implements Serializable {
#Inject
#ManagedProperty("#{msg}")
private Instance<ResourceBundle> bundle;
// ....
public void someAction() {
String message = bundle.get().getString("someLabel");
// ...
}
}
As the original question doesn't require injection, only asks how to access a resource bundle with the current locale, a solution without injection, and without the overhead of evaluating EL expression #{msg} every time bundle.get() is called would be:
#SessionScoped
public class UserBean implements Serializable {
#Inject
private FacesContext context;
// ...
public void someAction() {
ResourceBundle bundle = context.getApplication().getResourceBundle(context, "msg");
String message = bundle.getString("someLabel");
// ...
}
}
I have the impression that CDI is not working with classes that have a #javax.faces.component.FacesComponent. Is this true?
Here's my example, that doesn't work. The MyInjectableClass is used at other points in the code where injection is not a problem, so it must be about the #FacesComponent annotation I think.
The class I want to inject:
#Named
#Stateful
public class MyInjectableClass implements Serializable {
private static final long serialVersionUID = 4556482219775071397L;
}
The component which uses that class;
#FacesComponent(value = "mycomponents.mytag")
public class MyComponent extends UIComponentBase implements Serializable {
private static final long serialVersionUID = -5656806814384095309L;
#Inject
protected MyInjectableClass injectedInstance;
#Override
public void encodeBegin(FacesContext context) throws IOException {
/* injectedInstance is null here */
}
}
Unfortunately, even for JSF 2.2 #FacesComponent, #FacesValidator and #FacesConverter are not valid injection targets (read What's new in JSF 2.2? by Arjan Tijms for more details). As Arjan points out:
It’s likely that those will be taken into consideration for JSF 2.3 though.
What can you do for now? Well, you've got basically two choices:
Handle CDI injection via lookup, or switch to EJB and do the simpler EJB lookup;
Annotate tour class with #Named instead of #FacesComponent, #Inject the component the way you did and register your component in faces-config.xml. As the UI component instance is created via JSF Application#createComponent(), not via CDI you will also need a custom Application implementation as well (exactly like OmniFaces has for those converters/validators).
And, by the way, you've got two issues with what you've got this far: (1) what is meant by #Named #Stateful when the former is from a CDI world and the latter is from EJB world and (2) are you sure you intend to keep state in a faces component that's basically recreated on every request?
#FacesCompnent is managed by JSF and injection is not supported into them.
Passing the value in from the XHTML page via a composite component attribute worked for us.
how can I Inject a Bean, that uses a #Named annotation along with a value?
#Named
public class LanguageService{
...
}
public class SomeOtherBean{
#Inject
private LanguageService languageService
}
works without Problem - but how to inject, if i'm using:
#Named("lang")
public class LanguageService{
...
}
#Inject can't have a value as #ManagedProperty does. (But I wan't to stay with CDI)
Edit:
I noticed that it doesn't matter how the bean is named. My Fault that leads to an NPE was simple that i created SomeOtherBean manually, and ofc. no Injection was done. My fault.
CDI selects injectable beans by type (and qualifiers) and not by the annotation parameter. The name is used to address a CDI bean from views, e.g. facelets.
This question already has answers here:
How to inject #EJB, #PersistenceContext, #Inject, #Autowired, etc in #FacesConverter?
(5 answers)
Closed 6 years ago.
I have a stateless EJB that acceses my database.
I need this bean in a JSF 2 converter to retreive an entity object from the String value parameter. I'm using JEE6 with Glassfish V3.
#EJB annotation does not work and gets a NPE, because it's in the faces context and it has not access to the EJB context.
My question is:
Is it still possible to Inject this bean with a #Resource or other annotation, or a JNDI lookup, or do I need a workaround?
Solution
Do a JNDI lookup like this:
try {
ic = new InitialContext();
myejb= (MyEJB) ic
.lookup("java:global/xxxx/MyEJB");
} catch (NamingException e) {
e.printStackTrace();
}
I never used JSF 2.0 (only 1.0), but chapter 5.4 of the spec says:
[...] allow the container to inject references to
container managed resources into a managed bean instance before it is made accessible to the JSF application.
Only beans declared to be in request,
session, or application scope are
eligble for resource injection.
But so far I understand, a JNDI lookup should do the trick.
Other (yet not so pretty) solution may be using binding instead of converterId. Using JSF managed beans only:
<f:converter binding="#{app.personConverter}" />
Where appBean stands for something like:
#ManagedBean(name="app")
#ApplicationScoped
class AppBean {
#EJB
private PersonService ps;
private Converter personConverter;
}
There MAY be a nicer solution in CDI-style (JSR-299) but i've failed to make this one running:
<f:converter binding="#{cdiBean}" />
Where cidBean ought to be:
#Named class CdiBean implements Converter { #EJB ... }
Fails with 'Default behavior invoked of requiring a converter-id passed in the constructor'
Anyhow first approach using binding and app scoped JSF bean works.
The Seam Faces extension for JSF 2.0 and CDI allows #Inject support directly in Validators and Converters.
Check it out: http://ocpsoft.com/java/seam-faces-3-0-0-alpha2-jsf-2-0-just-got-even-easier/
i don't know if this solution is pretty... but it does work:
#ManagedBean
public class AcquisitionConverter implements Converter
{
#EJB
private AcquisitionService service;
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value)
{
...
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value)
{
...
}
}
and
<h:inputText value="#{flowController.acquisition}" converter="#{acquisitionConverter}">
with jsf 2.1.3 (mojarra) and glassfish 3.1.1