@PostConstruct in invoked everytime an event come

Question

I use CDI (Weld) in Java SE application. I made a Bean let's call it BeanA.

public class BeanA {
    @PostConstruct
    public void init() {
        System.out.println("INIT");
    }

    public void receive(@Observes String test) {
        System.out.println("received: " + test);
    }
}

In my test method I invoke:

Weld weld = new Weld();
WeldContainer container = weld.initialize();
Instance<BeanA> instance = container.instance().select(BeanA.class);
BeanA bean = instance.get();

container.event().fire("TEST");
container.event().fire("TEST");
container.event().fire("TEST");
container.event().fire("TEST");

Why output is like? Why @PostConstruct is called everytime event is received?:

INIT
INIT
recived: TEST
INIT
recived: TEST
INIT
recived: TEST
INIT
recived: TEST

score 6 · Answer 1 · edited May 23 '17 at 12:06

6

This is because the default scope of beans is @Dependent. This means that every time you fire an event, a new instance of your observer bean needs to be created so that the even gets sent to it. @PostConstruct gets invoked as part of that creation.

Annotate your BeanA type with @Singleton to set its scope to singleton. Only one will ever be created for your container.

edited May 23 '17 at 12:06

Community

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1

answered Nov 26 '14 at 22:36

Sotirios Delimanolis

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2

You're better off using `@ApplicationScoped` over `@Singleton`, the behaviour is the same but the CDI provided scope is normal. – John Ament Nov 27 '14 at 12:49
Ok but what if I want to have like 10 BeanA objects and send event to all of them? – ryan Nov 27 '14 at 20:42
@ryan I currently do not know how to do that. – Sotirios Delimanolis Nov 28 '14 at 06:43
@ryan please ask that as a separate question. – John Ament Nov 28 '14 at 13:37

@PostConstruct in invoked everytime an event come

1 Answers1