"Annotated" lambda expression instead of interface with single apply method

Question

instead of using anonymous classes like so

register(new EventListener() {
  @Override
  public void apply(Event e) {
    // do your work
  }
});

with java 8 I can use lambda expressions:

register(e -> (// do your work));

But what if the method in my interface is annotated?

interface EventListener {
  @Annotation
  void apply;
}

Is it possible to annotate a lambda expression? (Specifically, I want to use Guava's EventBus.register() method with lambda expressions)

you can implement an annotated interface method. Whether the library understands this is another question. — Peter Lawrey, May 31 '14 at 10:17

score 3 · Accepted Answer · edited May 23 '17 at 11:49

3

See this:

Annotating the functional interface of a Lambda Expression

Basically, you can't directly annotate in a lambda expression, but you can use the extending interface or class and access the annotation by calling Class#getAnnotatedInterfaces(). I believe that should answer your question.

Hope this helps,

Santiago

edited May 23 '17 at 11:49

Community

1
1

answered Jun 01 '14 at 19:13

Santiago Benoit

994
1
8
22

While the link might answer the question, you should at least include some form of explanation around it. – Rogue Jun 01 '14 at 19:20
Ok, thanks for the tip. I added a brief explanation. – Santiago Benoit Jun 01 '14 at 19:26

"Annotated" lambda expression instead of interface with single apply method

1 Answers1