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springaopspring-roo

Aspect to trap Controller creation in Roo project - how to?

I would like my first Aspect in a Roo project to run the advice when a web controller starts up. But I cant get the pointcut to match.

The controllers have a class name starting Cfx. I have tried with the following form:

pointcut setBrand() : initialization(Cfx*.new (..));

before()  : setBrand()
{
    log.info("xxxxxxxxxxxx  setting brand");
}

As well as "initialization" I have tried (from the book AspectJ Cookbook) call(Signature) with new keyword, preinitialization, staticinitialization. What is the formula?

Maybe this is related - the Roo aspects do not have this form - no pointcut for example. How are they working? Where is this documented?

Thanks

PS apologies, this is a re-post. I posted this to the Spring Roo forum but got no response. http://forum.springsource.org/showthread.php?129374-Aspect-to-trap-Controller-creation-how-to

Solution

  • I know next to nothing about Roo or Spring, but some AspectJ, so I am going to answer your question from an AspectJ perspective only, assuming that you are an AOP newbie (sorry if my assumption is incorrect):

    • If you want to do something when a class is loaded, use a staticinitialization(TypePat) pointcut.
    • If you want to do something when an object (instance) is created, use something like execution(ConstructorPat). The initialization is for special purposes and preinitialization is needed even more rarely. I am assuming that the first one will do for you, not knowing your exact purpose.
    • Further assuming that something like execution(Cfx*.new (..)) is basically the thing you want, I suggest you look at possible errors or warnings like "advice defined in ... has not been applied [Xlint:adviceDidNotMatch]", because it might just be a pointcut matching issue. Please note that the type pattern you use assumes the matched constructors are in the same package as the aspect and that they have standard visibility (not public or anything else). So unless there is a class-loading issue, maybe you just want to specify more exactly (or more generally) what you want to match. Examples:
      • com.bigboxco.my_app.Cfx*.new(..)
      • com.bigboxco..Cfx*.new(..)
      • public com.bigboxco..Cfx*.new(..)
      • !private com.bigboxco..Cfx*.new(..)
      • * com.bigboxco..Cfx*.new(..)

    A good strategy could be trying to match one of your constructors by replicating its exact signature and using its fully qualified class name, then working on from that point to make it more general.

    Update: I know you can do a web search by yourself, but anyway here are some useful links: