Puzzling first attempt...

[David Harrigan]

Hi,

Java 1.7u51

Reactor 1.1.0-BUILD-SNAPSHOT

Spring 4.0.1

I have Reactor configured thus:

@Configuration

@EnableReactor

@ComponentScan

public class PlatformConfiguration {

    @Bean

    public Reactor reactor(final Environment environment) {

        return Reactors.reactor(environment, RING_BUFFER);

    }

}

I have a controller that I'm playing around with, i.e.,

@RestController

public class PingController {

    public Callable<Long> ping() {

        return new Callable<Long>() {

            @Override

            public Long call() throws Exception {

                reactor.notify("do.me.a.ping", Event.wrap(new PingEvent("w00t")));

                return 1L;

            }

         }

      }

}

Then, in my Service, I have:

@Service

public class PingServiceImpl implements PingService {

    @Selector("do.me.a.ping")

    public void count2(final PingEvent pingEvent) {

        System.out.println(pingEvent.getMessage());

    }

}

When I spin this puppy up, Spring throws an exception:

2014-02-18 14:38:10.215:WARN:oejw.WebAppContext:main: Failed startup of context o.e.j.w.WebAppContext@10a74ad1{/,file:/home/foo/foo/jetty-distribution-9.1.2.v20140210/webapps/ROOT/,STARTING}{/ROOT}

org.springframework.expression.spel.SpelEvaluationException: EL1008E:(pos 0): Field or property 'reactor' cannot be found on object of type 'foo.bar.PingControlerImp$$EnhancerByCGLIB$$a577cfc5'

at org.springframework.expression.spel.ast.PropertyOrFieldReference.readProperty(PropertyOrFieldReference.java:217)

at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:85)

at org.springframework.expression.spel.ast.PropertyOrFieldReference.getValueInternal(PropertyOrFieldReference.java:78)

at org.springframework.expression.spel.ast.SpelNodeImpl.getValue(SpelNodeImpl.java:102)

at org.springframework.expression.spel.standard.SpelExpression.getValue(SpelExpression.java:94)

at reactor.spring.factory.config.ConsumerBeanAutoConfiguration.expression(ConsumerBeanAutoConfiguration.java:165)

at reactor.spring.factory.config.ConsumerBeanAutoConfiguration.fetchObservable(ConsumerBeanAutoConfiguration.java:169)

at reactor.spring.factory.config.ConsumerBeanAutoConfiguration.wireBean(ConsumerBeanAutoConfiguration.java:133)

at reactor.spring.factory.config.ConsumerBeanAutoConfiguration.onApplicationEvent(ConsumerBeanAutoConfiguration.java:108)

at reactor.spring.factory.config.ConsumerBeanAutoConfiguration.onApplicationEvent(ConsumerBeanAutoConfiguration.java:46)

I wonder if anyone would have an idea about what I've failed to do?

Thank you.

-=david=-

[Stephane Maldini]

Mmmh seems it does need the property Reactor to be locally injected. 

Can you try using the following field and re-run your test:

@AutoWired Reactor reactor

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[Jon Brisbin]

I suspect that's the problem. It's trying to figure out what Reactor you want to connect to but without one injected locally, it doesn't know.

You can also reference reactor="@reactorBeanName" in the annotation if you'd rather not inject the Reactor into your @Service.

Thanks!

Jon Brisbin | Reactor Project Lead

http://about.me/jbrisbin | @j_brisbin

[Stephane Maldini]

@AutoWired on a field require setter injection, just checking with you as it is easy to miss, have you got setReactor(Reactor reactor) ?

If you don't like setter injection you can use Constructor one. 

[Jon Brisbin]

FWIW- I generally prefer constructor injection and making injected fields final. But it's mostly a personal preference.

Thanks!

Jon Brisbin | Reactor Project Lead

http://about.me/jbrisbin | @j_brisbin

[David Harrigan]

Hi Everyone

Firstly, thank you to all for your kind replies.

I have got it to work following your suggestions. This is what I did

(I personally perfer setter injection....:-))

In PingServiceImpl:

private Reactor reactor;

@Resource

public void setReactor(final Reactor reactor) {

   this.reactor = reactor;

}

However, when I first did this:

@Selector(value = "request.order.count.event", reactor = "reactor")

It failed,

Then I did this:

@Selector(value = "request.order.count.event", reactor = "@reactor")

and it worked!

I think the default value in the annotation has the wrong default?. surely it should have "String reactor() default "@reactor"; and not just "reactor"?

-=david=- 

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[Jon Brisbin]

On Tuesday, February 18, 2014 at 9:32 AM, David Harrigan wrote:

However, when I first did this:

@Selector(value = "request.order.count.event", reactor = "reactor")

It failed,

This should mean, in SpEL terms "a property on the bean named 'reactor'". It's odd that it's not finding it. Is there a getter as well as a setter?

 

Then I did this:

@Selector(value = "request.order.count.event", reactor = "@reactor")

and it worked!

 

This means, in SpEL terms "a bean in the ApplicationContext called 'reactor'". Which may or may not be what you want, depending on what your service is doing.

I think the default value in the annotation has the wrong default?. surely it should have "String reactor() default "@reactor"; and not just "reactor"?

The safest default is to assume a property on the bean with the name "reactor" to make sure you don't "accidentally" pick up any one of a number of other Reactors that might be defined in the ApplicationContext.

[David Harrigan]

Hi,

I only have a setter on my service which takes the Reactor (configured as a @Bean in my Configuration class), as a @Resource and in the class itself it's just a private Reactor reactor. In 99.999% of my application, I use this paradigm, I setter inject with a private field on the class. I agree, surely the Service should be introspected, a field called Reactor found and used by the @Selector?

-=david=-

[Jon Brisbin]

On Tuesday, February 18, 2014 at 9:43 AM, David Harrigan wrote:

Hi,

I only have a setter on my service which takes the Reactor (configured as a @Bean in my Configuration class), as a @Resource and in the class itself it's just a private Reactor reactor. In 99.999% of my application, I use this paradigm, I setter inject with a private field on the class. I agree, surely the Service should be introspected, a field called Reactor found and used by the @Selector?

I seem to remember having issues with the way SpEL wants to interact with beans. I think this is one area I'm not a big fan of, but I'm pretty sure you need a public getter for SpEL to find the property (unless you change the way SpEL finds properties…I'm not sure there's an easy knob for that but I'll check).

[David Harrigan]

Hi,

Yes, urgh :-( 

If I put a 

public Reactor getReactor() {

return reactor;

}

on my service, and change the @Selector just to have the key (with no reactor = "@reactor"), then it boots.

-=david=-

[David Harrigan]

Urrgh

Bizarrely,

If I *remove* the setter and getter from the service and simply do @Autowired private Reactor reactor, then it _fails_ to boot.

-=david=-

[Jon Brisbin]

What if you inject the Reactor into a final private field and provide only a getter?

Thanks!

Jon Brisbin | Reactor Project Lead

http://about.me/jbrisbin | @j_brisbin

[David Harrigan]

Hi,

That works. 

I guess it's all a little confusing. I was following the example as laid out here http://goo.gl/O0hJTP. There are no public getter methods (on the AnnotatedHandler) so nothing to suggest that I would need one. 

It feels like a problem with spEL? It's a bit ugly to expose a getter for a field that Spring is injecting, but then spEL can't find.

To recap:

@Autowired private Reactor reactor works only if there is a corresponding getReactor() on the class.

Using @Resource setReactor only works if there is a corresponding getReactor() on the class.

@Autowired on a field by itself or @Resource on a setter by itself do not work without a getReactor() on the class.

-=david=-

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