Is there a way to know if a state is active without catching ContextNotActiveException?

问题

I would like to know if the RequestScoped context is currently active in a method or not.

At the moment, here is what I do :

@Inject private BeanManager beanManager;

public boolean isRequestScopeActive() {
    try {
        if (beanManager.getContext(RequestScoped.class).isActive()) {
            return true;
        } else {
            return false;
        }
    } catch (final ContextNotActiveException e) {
        return false;
    }
}

I think it's a bit heavy to catch a ContextNotActiveException just to know if a scope is active or not.

Do you have any better way to know the state (active or not) of a context in CDI ?

回答1:

Yeah, the only option we have in CDI 1.0 is to catch the ContextNotActiveException. This actually ends up being a big problem for apps scoped, where the scope implementation is not available for injection. E.g. You can't just @Inject RequestScopedContextImpl rq; and check the .isActive() method, because we don't have access to that class without knowing the implementation details.

来源：https://stackoverflow.com/questions/11507109/is-there-a-way-to-know-if-a-state-is-active-without-catching-contextnotactiveexc