I agree with Simone. There isn't a good way to effectively find out all aspects using some classpath scanning mechanism. Note, however, that there is an -outxml (or -outxmlfile <file>) option to 'ajc' that will create aop.xml with an entry for all aspects. -Ramnivas
2008/10/2 Simone Gianni <[EMAIL PROTECTED]> > Hi Janos, > unfortunately, at least AFAIK, there is no method in ClassLoader to find > "all resources" in a package. The getResource (findResource, > findResources etc..) only find resources if you already know the > complete name of them (complete package). A number of tricks exists, > like obtaining the path of the jar, then opening it as if it was a zip > file, and scanning its content .. but they are not applicable in an > "enterprise" like environment, where a hierarchy of classloaders may be > in place and no direct access to jar files is possible (or even, there > are no jar files at all). I also feel like this is a problem, but it's a > ClassLoader problem in general, nothing AspectJ can easily fix. > > Anyway, exploring all possible classes for the presence of an annotation > would be far too heavy. In even a simple web project there can be > thousands of classes, scanning all of them so see which are aspects > before even starting the "main" could require several seconds if not > minutes. > > I can't think of any way to avoid the .xml file, maybe there is one, but > without explicit support from the ClassLoader interface or some other > java compiler internals (like a quick way to find all classes having a > specific annotation, that would benefit quite a bit also JPA providers > for example, which are also bound to XML based class listings in most > cases) I think it's hard to do it in a reliable and standards compatible > way. I don't think even a standard annotation processor could somehow > ease this. > > Simone > > Háber János wrote: > > Hmm! > > > > Tanks. > > > > " but have no idea that it exists an aspect"? > > > > Maybe a solution: Spring solve this probelm with a very simply way. > > Get the selected package (maybe in aspectj possible using <include> > > for this) and get all file-s and directories with > > classloader.getResource method. And if the selected class is an > > @Aspect... load it... > > > > > > Janos > > > > > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] On Behalf Of Simone Gianni > > Sent: Thursday, October 02, 2008 3:17 PM > > To: aspectj-users@eclipse.org > > Subject: Re: [aspectj-users] LTW and annotations > > > > If I understand how LTW works correctly, the problem is in class > > loading. > > > > Consider the situation where you have a bean with a doSomething > > method, > > and then have an advice that does something before that method. > > > > You application starts, it will load the bean with a new Bean(). At > > this > > point, the class loader loads the bean, but have no idea that it > > exists > > an aspect, so will not weave the bean. This is because, you never call > > (and have explicitly no way) to call "new MyAspect()". > > > > In fact, if you had such a way of instantiating aspects, another > > situation could arise and cause problems. Suppose you have also a > > tracing aspect, that will intercept all calls to all methods. If this > > tracing aspect gets loaded AFTER the bean has already been loaded, the > > class loader is not able anymore to modify the bean, because it has > > already been loaded. > > > > (in reality, there are some ways to do class redefining in recent > > classloaders, but that brings another lot of problems) > > > > So, yes, you have to define your aspects in the aop.xml file. Since > > this > > is tedious, the ajc compiler can perform this task for you. If you are > > using AJDT in Eclipse, there is an option for generating aop.xml on > > the > > fly under the AspectJ section of you settings. If you are compiling > > from > > command line using ajc, the -outxml option will generate it for you > > (see > > http://www.eclipse.org/aspectj/doc/released/devguide/ajc-ref.html ). > > Also, the maven2 plugin for aspectj will generate the aop.xml file for > > you. > > > > Hope this helps, > > Simone > > > > > > > > Háber János wrote: > > > >> Hi! > >> > >> I have a question. I want to write an application. I using javaagent > >> vm option to LTW. But in this case what needed in aop.xml (aop.xml > >> required in this case if I not want to set any special weaving > >> options?) > >> If I only write: > >> <aspectj> > >> <weaver options="-verbose -showWeaveInfo"/> > >> </aspectj> > >> > >> I get: "no aspects registered. Disabling weaver for class loader..." > >> WTF? I need to set the aspects both aop.xml and annotation in java > >> file? Why? > >> If Yes, why? The classloader can't detect the annotations? > >> > >> > >> Janos Haber > >> > >> _______________________________________________ > >> aspectj-users mailing list > >> aspectj-users@eclipse.org > >> https://dev.eclipse.org/mailman/listinfo/aspectj-users > >> > >> > > > > > > > > > -- > Simone Gianni CEO Semeru s.r.l. Apache Committer > MALE human being programming a computer http://www.simonegianni.it/ > > _______________________________________________ > aspectj-users mailing list > aspectj-users@eclipse.org > https://dev.eclipse.org/mailman/listinfo/aspectj-users >
_______________________________________________ aspectj-users mailing list aspectj-users@eclipse.org https://dev.eclipse.org/mailman/listinfo/aspectj-users
