How to call managed bean inside of stateless EJB bean?

Question

I wanted to know, is there any option to call a managed bean inside of EJB bean. Imagine, we have the code:

@ManagedBean
@SessionScoped
public class MyManagedBean implements Serializable {
  public String getUrl() {
      return "http://www.google.com";
  }
}

@Stateless
public class MyEJB {

  @ManagedProperty(value = "#{myManagedBean}")
  MyManagedBean myManagedBean;

  public void setMyManagedBean(MyManagedBean myManagedBean) {
      this.myManagedBean = myManagedBean;
  }

  public void call() {
      // NullPointerException here
      System.out.println(myManagedBean.getUrl());         
  }
}

I also tried this:

@Stateless
public class MyEJB {
  @EJB
  MyManagedBean myManagedBean;
  ...
}

... but it returns different MyManagedBean instance.

Check http://stackoverflow.com/questions/8626291/jsf-managed-bean-ejb-injection — Johny T Koshy, Sep 26 '13 at 11:13
@johny, That's not my case: that guy asks how to call EJB inside managed bean, but I need to call managed bean inside EJB — Exterminator13, Sep 26 '13 at 11:18
No, there is no way. The EJB container is not aware of the JSF context of the bean you want to inject. Knowing the concrete problem you are facing would help to find valid alternatives. — perissf, Sep 26 '13 at 11:30
Why would you want to inject a jsf bean into stateless EJB or any EJB? — Johny T Koshy, Sep 26 '13 at 11:33
@perissf, have a managed bean where I store some data for current session (user login and credentials if it does matter) - that's "myManagedBean". "MyEJB" returns some data from database. What data return depends on user account type. — Exterminator13, Sep 26 '13 at 11:36
@johny, because it stateless and cannot have any state (fields) in it, because lifecycle of it is undefined — Exterminator13, Sep 26 '13 at 11:45

score 3 · Accepted Answer · edited May 23 '17 at 12:33

3

This is not right. With CDI managed beans instead of JSF managed beans it's possible, but it is just not right as in, bad design. The business service should not be aware about the front-end at all. It makes the business service unreusable on other front-ends than JSF.

You should do it the other way round. You should inject the EJB in the managed bean, not the other way round. The EJB should be kept entirely stateless. You should just directly pass the EJB the information it needs as method argument (and never assign it as instance variable of EJB afterwards).

E.g.

@ManagedBean
@SessionScoped // <-- Did you read https://stackoverflow.com/q/7031885?
public class MyManagedBean implements Serializable {

    private String url = "http://www.google.com";

    @EJB
    private MyEJB myEJB;

    public void submit() {
        myEJB.call(url);
    }

    public String getUrl() {
        return url;
    }

}

and

@Stateless
public class MyEJB {

    public void call(String url) {
        // No NullPointerException here.
        System.out.println(url);
    }

}

How to call managed bean inside of stateless EJB bean?

1 Answers1

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