Re: [aspectj-users] Java 9+ modules questions

["Alexander Kriegisch" <alexander@xxxxxxxxxxxxxx>]

Okay I found these tests:
https://github.com/eclipse/org.aspectj/tree/master/tests/bugs190/modules

They are executed according to this configuration:
https://github.com/eclipse/org.aspectj/blob/master/tests/src/test/resources/org/aspectj/systemtest/ajc190/ajc190.xml

But I found no cases there in which both application and aspect module
have module info files. The aspect always seems to be compiled without
module info. In a way I understand that, because aspects are kind of
orthogonal (as in cross-cutting) to aspects. Usually we do not want an
application to be dependent on aspects and some more generic aspects
should run with many different types of applications. So here we are
hitting JMS limits. As a result, I cannot e.g. put an aspect module on
an application module's module path in order to access e.g. an
annotation contained in the aspect library along with the aspect. Ajc
throws compile errors in this case. I would have to factor out the
annotation into a separate module, so the application can use the
annotation without the aspect. But then again the application must not
contain a module info file, otherwise I get compile errors again because
it cannot find the aspect (JMS) module. For now, whatever I am trying to
do, the artifact containing aspect-woven code must refrain from defining
a module info, AFAIU effectively breaking the encapsulation intended by
previous JMS usage and putting everything into the default module,
basically reverting it back to Java 8 standard.

As for myself, I never used JMS before because for me it seems to bring
more problems than benefits. For pure OOP-style applications JMS might
work nicely and promote encapsulation and clean service interfaces,
which is definitely something we would want. In order to marry the JMS
concept with AOP though, I think the way it is implemented now makes the
two of them more or less incompatible.

-- 
Alexander Kriegisch
https://scrum-master.de


Alexander Kriegisch schrieb am 18.12.2020 09:59 (GMT +07:00):

> All documentation I can find concerning JMS support in AspectJ 1.9.x
> is this: https://www.eclipse.org/aspectj/doc/released/README-190.html
> 
> I also see a few unimplemented features:
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=526242
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=526243
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=526244
> 
> After adding support for 'ajc --module-path' to AspectJ Maven plugin I
> experimented a bit with multi-module projects and found that it seems
> to be impossible to do binary weaving by putting any AspectJ module (I
> mean both Maven and JMS module with module-info.java) on the
> aspect-path. In the read-me mentioned above there is just an example
> of weaving the other way around, i.e. putting the target application
> on the aspect module's in-path. Is that due to the missing
> implementation of #526243? It does not help much if Ajc can compile
> projects with module-info files but does not respect JMS semantics in
> multi-module projects.
> 
> Maybe I am doing something wrong. Are there any instructive tests in
> the AspectJ source code you could point me to? The AspectJ module
> structure is complicated, it is kind of difficult to find anything
> there.