有没有什么好方法可以在其构造函数中创建带有某些参数的新Object并在其中注入CDI bean？

Question

Example:

@Dependant 
public class SomeStartingPoint {

@Inject
private SomeService someService;

   public void doSomething(Long aLong, MyCustomObject myObject) {
       NotABean notABean = new NotABean(aLong, myObject);
       someService.doStuffWithNotABean(notABean);
   }
}


public class NotABean {

@Inject
private WouldBePerfectIfThisWouldBeManagedBean somehowInjectedBean;

   public NotABean(Long aLong, MyCustomObject myObject) {
      //set state
   }
}

So the question is, is there a nice way to have something injected into the NotABean object, which supposed to have state in it, thus created by new()?

Of course, in current situtation I could pass WouldBePerfectIfThisWouldBeManagedBean as an argument to constructor, but this is not related to the question.

Answer 1

There's a CDI 1.0 way and a CDI 1.1 way to do this. The 1.1 way is much easier than 1.0, hence why they created it.

Here's an example from DeltaSpike: https://github.com/apache/deltaspike/blob/34b713b41cc1a237cb128ac24207b76a6bb81d0c/deltaspike/core/api/src/main/java/org/apache/deltaspike/core/api/provider/BeanProvider.java#L437

    CreationalContext<T> creationalContext = beanManager.createCreationalContext(null);

    AnnotatedType<T> annotatedType = beanManager.createAnnotatedType((Class<T>) instance.getClass());
    InjectionTarget<T> injectionTarget = beanManager.createInjectionTarget(annotatedType);
    injectionTarget.inject(instance, creationalContext);

Assuming you have an instance of some object that has fields or methods annotated @Inject it will satisfy those dependencies.

In CDI 1.1, you can do the opposite. Using the class Unmanaged you can instantiate unmanaged instances of your class. You would need to call setters afterwards to set the values.

   Unmanaged<Foo> fooU = new Unmanaged(Foo.class);
   Foo foo = fooU.newInstance().get();

One other way, without using @Inject is to use the CDI 1.1 utility class to manually get references. So instead of injecting a reference to SomeService you could do:

   SomeService someService = CDI.current().select(SomeService.class).get();