jsf - How to @Inject in a PhaseListener

Question

I have added a PhaseListener to faces-config.xml:

<lifecycle>
    <phase-listener>com.project.NotificationListener</phase-listener>
</lifecycle>

The class seems to be otherwise correct as it is pretty simple.

public class NotificationListener implements PhaseListener {

    @Inject
    private MyCDIStuff stuff;

    @Override
    public PhaseId getPhaseId() {
        return PhaseId.RENDER_RESPONSE;
    }

    @Override
    public void beforePhase(PhaseEvent event) {
        this.stuff.doStuff();
    }
}

The 'beforePhase' method gets called correctly, however the MyCDIStuff object is null. I tried using annotation @Singleton for the class which most likely was incorrect, and it didn't make the injection work either.

Is there a way to inject CDI managed beans in the PhaseListener?

Answer 1

Before JSF 2.2, PhaseListeners are not registered as CDI injection targets. Using @Inject (and @EJB) has effectively no effect in PhaseListeners. You'd need to manually grab the CDI managed beans by programmatically evaluating an EL expression referencing the @Named's (implicit) name, or as last resort via JNDI and BeanManager which is quite clumsy.

So, if you can't upgrade to JSF 2.2 (which should be compatible with any JSF 2.0/2.1 and Servlet 3.0 compatible web application), then your best bet is programmatically evaluating an EL expression referencing the @Named name. Assuming that you've a

@Named("stuff")
public class MyCDIStuff {}

then this should do:

FacesContext context = event.getFacesContext();
MyCDIStuff stuff = context.getApplication().evaluateExpressionGet(context, "#{stuff}", MyCDIStuff.class);
// ...