Precedence on @Observes

[jonh.wendell]

Hi folks.

I have an Arquillian extension that registers (a) an observer and (b) an enricher service.

Here's the skeleton of the observer:

public class Initializer {
    @Inject
    @ApplicationScoped
    private InstanceProducer<Configuration> configurationProducer;

    public void configure(@Observes ArquillianDescriptor arquillianDescriptor, org.arquillian.cube.kubernetes.api.Configuration cubeConfig) {
        Configuration config = Configuration.fromMap(arquillianDescriptor.extension("my-extension").getExtensionProperties());

        configurationProducer.set(config);
    }    
}

The enricher service relies on the Configuration object set above:

public class MyEnricher implements TestEnricher {
  @Inject
  private Instance<Configuration> configurationInstance;

  ... (within a method:)
  Configuration config = configurationInstance.get();
}

The problem is that the statement configurationInstance.get(); above (line 6) is sometimes returning null. Sometimes it works fine. I believe this is happening because the time this line is executed the producer above hadn't been executed.

So, is there a way to set a dependency here? I mean, this enricher should only be called after the producer above actually set the value of the Configuration object?

Thanks.

[iocanel]

There is always one observer which upon a predefined event performs some tasks.

In your case, that observer is started, earlier than it should, or at least before all the actual requirements are fulfilled.

I would search to find which is that observer (the stack trace would easily reveal that) and I would try to express the dependency on that observer (e.g. by having it observer the configuration object). If this doesn't solve the issue I would create and fire a new event that will signal that all requirements are fullfilled.

In cube kubernetes, we do something similar: "When the configuration and the logger are available we produce a session and then we fire the start event".

[bmajsak]

Custom events and observes sounds like a feasible thing to do.

In order to see exact events/observers flow you can also enable debug mode and it will be logged at runtime. Simply set -Darquillian.debug=true