I have a context-param in web.xml:
<context-param>
<description>Version number will be prefixed to url of requests</description>
<param-name>version_id</param-name>
<param-value>11</param-value>
</context-param>
I want to inject this into a ManagedBean
This bean has a scope None
I tried the code below but it's not working, I'm getting an exception on startup with this error:
The scope of the object referenced by expression #{initParam[version_id]}, application, is shorter than the referring managed beans (responseData) scope of none
#ManagedBean
#NoneScoped
public class ResponseData implements Serializable {
#ManagedProperty(value = "#{initParam.version_id}")
private String version;
public ResponseData() {
}
/**
* #param version the version to set
*/
public void setVersion(String version) {
this.version = version;
}
}
What is the right way to inject value of context-param into a managed bean as a managed property?
What you are attempting is that you are trying to get the value of a managed property that has a smaller scope than the ResponseData managed bean that is NoneScoped.
You should be able to get the context params from the ServletContext however without needing to reference another bean.
ServletContext servletContext = (ServletContext) FacesContext
.getCurrentInstance().getExternalContext().getContext();
servletContext.getInitParameter("version_id");
Related
I am new to jsf and using JSF 2.0 to keep user information in a session scoped bean. I need to access this information across other beans for grunt work. Presently, this is how i am doing:-
private UserBean myuser1 = (UserBean)FacesUtils.getManagedBean("UserBean");
and then access properties as
if (myuser1.getUserType == 1) ...
this works but some time throws Argument Error: parameter key is null exception. I have been using following method too:-
private UserBean myuser2 = new UserBean();
if (myuser2.getUserType == 1) ...
In second method, my understanding is that if UserBean is already created in session, it would be retried. There are lots of question about 'how to access one bean in another' so i am confused. Please tell me one clean method which should always work and not throw null pointer exception abruptly.
The simplest way I know of is using #ManagedProperty, I don't know what you mean by safest though.
Let's say this is your sessionScoped bean :
#ManagedBean
#SessionScopped
public class UserBean {
//bean attributes and methods
}
Then you can access it in any other bean (provided it has the same or a narrower scope) as an attribute like this :
#ManagedBean
#ViewScoped //in this cas you can use SessionScoped, FlowScoped, or RequestScoped too
public class AnotherBean {
#ManagedProperty("#{userBean}")
UserBean userB;
//rest of the bean
//be sure to add getters and setters for the injected bean
}
For more details check this
Hope this helps.
Actually,
parameter key is null exception: it's either you didn't initialize the object witch can be solver with either adding
object = new Object(); // in the constructor of the class.
The second problem may be that the object is " DETACHED " you need to call the object using the method merge (with the entity manager).
A detached object is a known value but the JPA system doesn't know if it is the latest version from the DB or even sometimes the id value is not set for some reason (Not managed with jpa in other words it can be your case).
If em is your entity manager and you have the following function:
public Object latestVersion(Object o){ em.merge; }
In your Bean with:
#EJB
Service service;
if you do em.latestVersion(o); the problem of detached object is solved.
And for the real answer:
To access a object from another view you can simply do the following.
#ManagedBean
#SessionScoped
..... Bean1 {
public static Object o;
.....
}
#ManagedBean
..... Bean 2 {
private Object b=Bean1.o;
.....
}
Good luck
The standard practice of setting dependency of a scoped bean in another scoped bean is to use #Inject annotation like
#Inject UserBean userBean; in the bean you want use the UserBean object.
Your UserBean should be a stateful one.
#Stateful
#LocalBean
public class UserBean
{
private String name;
public String getName() { return name; }
public void setName( String name_ ) { name = name_; }
}
And just inject it into a stateless bean to modify its state:
#Stateless
#LocalBean
public class MyStatelessBean
{
#EJB
private UserBean userBean;
public String getUserName() { userBean.getName(); };
public void setUserName( String name_ ) { userBean.setName( name_); }
}
Or you can access it from (not wider scoped) managed beans as well in the same way:
#ManagedBean
#Dependent
public class MyJSFManagedBean
{
#EJB
private UserBean userBean;
}
You wrote in your comment you does not use EJBs at all. The picture modify like this:
The UserBean should be a SessionScoped CDI bean
#Named
#SessionScoped
pubilc class UserBean
{}
The othe CDI bean should be in a nearer scope:
#Named
#Request // or #ViewScoped or #Dependent
public class OwnerBean
{
#Inject
UserBean userBean;
}
The container automatically takes care to create the beans in the right scope and insert them into the owers (any kind of container managed objects : servlets, filters, action listeners, JSF/CDI beans). You need to insert a wider scoped resource into a thinner scoped one.
I'm trying to use an application scoped bean in JSF2, but for some reason it is always null in my request scoped bean. Here's the code I'm using:
The application scoped bean:
#ManagedBean(eager=true, name="applicationTracking")
#ApplicationScoped
public class ApplicationTracking implements Serializable {
private static final long serialVersionUID = 4536466449079922778L;
public ApplicationTracking() {
System.out.println("ApplicationTracking constructed");
}
}
The request scoped bean:
#ManagedBean
#RequestScoped
public class SearchResults implements Serializable {
private static final long serialVersionUID = 4331629908101406406L;
#ManagedProperty("#{applicationTracking}")
private ApplicationTracking appTracking;
public ApplicationTracking getAppTracking() {
return appTracking;
}
public void setAppTracking(ApplicationTracking appTrack) {
this.appTracking = appTrack;
}
#PostConstruct
public void init() {
System.out.println("SearchResults.init CALLED, appTracking = " + appTracking);
}
}
According to everything I'm seeing in the forums this should work without any other configurations. When I start the server (Tomcat) I'm seeing the ApplicationTracking constructor and init methods getting called.
But in my SearchResults component the printout in the PostConstruct is always null:
SearchResults.init CALLED, appTracking = null
What am I missing?
Provided that you imported those annotations from the right package javax.faces.bean.*, then this problem will happen if you re-registered the very same managed bean class in faces-config.xml on a different managed bean name. Get rid of that faces-config.xml entry. That's the JSF 1.x style of registering managed beans. You don't need it in JSF 2.x. When you do so anyway, then it will override any annotation based registration on the managed bean class, causing them to be ineffective.
Make sure you don't read JSF 1.x targeted resources while learning and working with JSF 2.x. Many things are done differently in JSF 2.x.
I am using TomEE+ 1.7.1.
With JSF managed beans this code was working well:
#ManagedBean( eager = true )
#ApplicationScoped
public class AppBean {
#PostConstruct
public void init() {
ServletContext sc = (ServletContext) FacesContext.getCurrentInstance().getExternalContext().getContext();
if (GlobalSettings.TESTMODE) {
sc.getSessionCookieConfig().setDomain("." + GlobalSettings.APP_DOMAIN_TEST);
} else {
sc.getSessionCookieConfig().setDomain("." + GlobalSettings.APP_DOMAIN);
}
}
}
The init function ran at application startup and ServletContext was available.
I read everywhere that it's time to migrate to CDI beans instead of JSF beans. So I wanted to change #ManagedBean( eager = true ) to #Named #Eager (#Eager is from Omnifaces). Init function is running at application startup, but there is no FacesContext so I can't get ServletContext.
General question: How to get ServletContext in a non-request environment in CDI beans? (ServletContext is not a 'per request' object, so it should exist before the first request.)
Specific question: how to set the domain for the session cookies dynamically from code but before the first request occurs?
You should be using a ServletContextListener for the purpose of performing programmatic configuration on a servlet based application.
#WebListener
public class Config implements ServletContextListener {
#Override
public void contextInitialized(ServletContextEvent event) {
ServletContext servletContext = event.getServletContext();
// ...
}
#Override
public void contextDestroyed(ServletContextEvent event) {
ServletContext servletContext = event.getServletContext();
// ...
}
}
A #WebListener is inherently also CDI managed and thus you can just use #Inject and friends in there.
An application scoped managed bean is intented for holding application scoped data/state which can be used/shared across requests/views/sessions.
Per the CDI spec, you can #Inject the ServletContext into a CDI bean. Just be sure to do it in a #PostConstruct, as injected fields are available only after construction:
#Inject ServletContext extCtxt;
#PostConstruct
public void doSomething(){
// do something with your injected field
}
As the title implies, I'm trying to inject a view scoped bean into a validator decorated by #FacesValidator as follows.
#FacesValidator(value = "priceRangeValidator")
public final class PriceRangeValidator implements Validator {
#ManagedProperty(value="#{rangeSliderBean}")
private RangeSliderBean rangeSliderBean; //Setter only.
#Override
public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
// The bean instance is unavailable here. It is null.
}
}
The target view scoped bean - RangeSliderBean is unavailable in the validate() method.
I'm temporarily following the following way to get an instance of that bean in the validate() method itself.
RangeSliderBean rangeSliderBean = context.getApplication().evaluateExpressionGet(context, "#{rangeSliderBean}", RangeSliderBean.class);
Is it possible to inject a view scoped JSF managed bean into a validator using the #ManagedProperty annotation or something else?
I'm using JSF 2.2.6.
UPDATE:
This does not work on Mojarra 2.3.0-m01. The bean instance still remains null as it did before. This time long after this post, I took a corresponding view scoped CDI bean (#ManagedProperty was replaced by #Inject).
Try dynamic Injection by evaluating an expression using Application like this.
FacesContext facesContext = FacesContext.getCurrentInstance();
RangeSliderBean rangeSliderBean = facesContext.getApplication().evaluateExpressionGet(facesContext, "#{rangeSliderBean}", RangeSliderBean .class);
Ok here is my session bean. I can always retrieve the currentUser from any Servlet or Filter. That's not the problem The problem is the fileList, and currentFile. I've tested with simple int's and Strings and its' the same effect. If I set a value from my view scoped bean I can get the data from another class.
#ManagedBean(name = "userSessionBean")
#SessionScoped
public class UserSessionBean implements Serializable, HttpSessionBindingListener {
final Logger logger = LoggerFactory.getLogger(UserSessionBean.class);
#Inject
private User currentUser;
#EJB
UserService userService;
private List<File> fileList;
private File currentFile;
public UserSessionBean() {
fileList = new ArrayList<File>();
currentFile = new File("");
}
#PostConstruct
public void onLoad() {
Principal principal = FacesContext.getCurrentInstance().getExternalContext().getUserPrincipal();
String email = principal.getName();
if (email != null) {
currentUser = userService.findUserbyEmail(email);
} else {
logger.error("Couldn't find user information from login!");
}
}
Here is an example.
My view scoped bean. This is how it is decorated.
#ManagedBean
#ViewScoped
public class ViewLines implements Serializable {
#Inject
private UserSessionBean userSessionBean;
Now the code.
userSessionBean.setCurrentFile(file);
System.out.println("UserSessionBean : " + userSessionBean.getCurrentFile().getName());
I can see the current file name perfectly. This is actually being printed from a jsf action method. So obviously the currentFile is being set.
Now if I do this.
#WebFilter(value = "/Download")
public class FileFilter implements Filter {
#Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
HttpSession session = ((HttpServletRequest) request).getSession(false);
UserSessionBean userSessionBean = (UserSessionBean) session.getAttribute("userSessionBean");
System.out.println(userSessionBean.getCurrentUser().getUserId()); //works
System.out.println("File filter" + userSessionBean.getCurrentFile().getName()); //doesn't work
chain.doFilter(request, response);
}
#Override
public void init(FilterConfig filterConfig) throws ServletException {
}
#Override
public void destroy() {
}
}
currentUser shows up fine but I can't see the file. It's just blank. The same thing happens with Strings, int's, etc.
Thanks for any help you can provide on this.
INFO: UserSessionBean : Line 3B--8531268875812004316.csv (value printed from view scoped bean)
INFO: File filter tester.csv (value printed when filter is ran.)
**EDIT**
This worked.
FacesContext context = FacesContext.getCurrentInstance();
userSessionBean = (UserSessionBean) context.getApplication().evaluateExpressionGet(context, "#{userSessionBean}", UserSessionBean.class);
I put this in the constructor of the ViewScoped and everything was fine. Now why isn't the inject doing what I thought? At first I thought maybe because I was using JSF managed beans instead of the new CDI beans. But I changed the beans to the new style(with named) and that was the same effect.
Does the inject only allow you to access the beans but not change their attributes?
You're mixing JSF and CDI. Your UserSessionBean is a JSF #ManagedBean, yet you're using CDI #Inject to inject it in another bean. CDI doesn't reuse the JSF managed one, it instead creates a brand new one. Use the one or the other, not both. The correct annotation to inject a JSF-managed bean is #ManagedProperty.
Replace
#Inject
private UserSessionBean userSessionBean;
by
#ManagedProperty(value="#{userSessionBean}")
private UserSessionBean userSessionBean;
and ensure that you don't have a import javax.enterprise.context anywhere in your code (which is the package of CDI annotations).
Alternatively, migrate all JSF bean management annotations to CDI bean management annotations.
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
#Named
#SessionScoped
public class UserSessionBean implements Serializable {}
import javax.inject.Named;
import javax.faces.view.ViewScoped;
#Named
#ViewScoped
public class ViewLines implements Serializable {}
Additional advantage is that you can just #Inject it inside a regular servlet or filter without the need to manually grab it as request/session/application attribute.
Moreover, JSF bean management annotations are deprecated since JSF 2.3. See also Backing beans (#ManagedBean) or CDI Beans (#Named)?
My best GUESS as to why this is happening, is because the variable file, is being set in view scope, and then passed by reference into the session scoped bean. Maybe this is happening because when the view scope bean is destroyed, it still has a reference to that variable, but doesn't bother to see if there's any other references to it in session scope, where it should be preserved. Hence, when it's destroyed, it's removed from both view and session scope in this case.
Could you try calling setCurrentFile with an object instantiated with 'new'? That might prove or disprove this hypothesis of mine.
Otherwise, my best advice would be to crack open the debugger, and see exactly where getCurrentFile is being changed.