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Using AspectJ, how do you replace an existing annotation?

I have the following code

declare @method : @Test * *(..) : @Test(timeout=10);

Which generates the following error on every test method:

... already has an annotation of type org.junit.Test, cannot add a second
instance [Xlint:elementAlreadyAnnotated]

Of course, the error makes sense but what is the syntax to say, "remove the @Test annotation from all methods that have it. Then replace it with @Test(timeout=10)"

gMale
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2 Answers2

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I'm the AspectJ project lead. Under https://bugs.eclipse.org/bugs/show_bug.cgi?id=313026 we are looking at how to use declare annotation for:

  • augmenting existing annotations (adding values to those that are already there)
  • replacing them
  • defining precedence (should your declare replace what is there?)

We are also looking at a form of it that removes annotations:

declare @remove_from_method: int mymethod(): @ToBeRemoved;

But you can't do it yet...

Andy Clement
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  • Thanks for the update. I've logged in added some votes on the bug. I would love that feature. It feels like creating a work-around is a fairly ugly process. – gMale Dec 20 '10 at 01:44
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I doubt that you can do that with AspectJ. At least I could not find any relevant info in the current version of AspectJ in Action.

What you can do is inject your own custom annotation next to the test annotation and write a custom JUnit Runner class (bound with the @RunWith annotation, which you can again inject with your aspect) that gives your custom annotation precedence over the @Test annotation.

Sean Patrick Floyd
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  • Funny, that's the same book I have open on my desk, right now. lol. I like where you're going with this. I've written a few mixins so I'm somewhat comfortable with making classes do completely different things (like extend something else). One problem with your suggestion though: my test classes already use the @RunWith annotation. I wonder if this could work if I make all tests extend a parent class that uses a custom @RunWith, as you mentioned – gMale Nov 05 '10 at 14:02
  • The parent class approach will work (`@RunWith` is marked with `@Inherited`), but if the child classes contain the annotation, the child annotation wins over the parent annotation. – Sean Patrick Floyd Nov 05 '10 at 14:09