Re: [aspectj-users] Status of using XML config, as opposed to language-b

[Michael Nascimento <misterm@xxxxxxxxx>]

There's a major difference between deployment descriptor (for EJBs,
for example) and aspects. In the first case, generally the
configuration is already known by the one writing the component and it
never make any sense to have to switch to a XML file to configure it.
Most EJBs and DD-driven components are not reusable by nature.

However, an aspect is (and most of the times should be) designed for
reusability, so it's important to be able to edit its pointcuts and/or
deployment model without touching source code, since aspects could -
and I guess they will be more and more - provided by a third party and
used more like a library by the final developer.

It is obvious there are exceptions to both rules - reusable EJBs, for
example, or very specific aspects -, but it's good to be able to
override things in a configuration file.

If you are writing an AOP-based framework - genesis (
https://genesis.dev.java.net ), which relies on AspectWerkz is one
example -, you do want to define certain parts of your aspect in the
source code itself, but you do want the end user to be able to write
any pointcuts to want, choose which aspects to apply, change their
deployment models, provide parameters etc., and all of this without
changing the source code, which would simply prevent adoption
depending on the license of your software.

So I guess both approaches are valuable, but external configuration
files are essential for those writing AOP-based frameworks.

Regards,
Michael Nascimento Santos
https://genesis.dev.java.net/

On 4/17/05, Ted Neward <ted@xxxxxxxxxx> wrote:
> Let me suggest that one of the strengths of AspectJ (as opposed to other
> AOP-ish tools) is that it in fact does everything inside the language, as
> opposed to external files like XML configuration files. One of the reasons
> JSR 175 was formed was to do away with "external" code-like artifacts, like
> deployment descriptors, and I'd hate to see us go back to a mechanism that
> forces developers to keep code-like entities in two places at once.
> 
> Ted Neward
> Author, Instructor, Consultant
> Java, .NET, Web services
> http://www.neward.net/ted
> 
> > -----Original Message-----
> > From: aspectj-users-bounces@xxxxxxxxxxx [mailto:aspectj-users-
> > bounces@xxxxxxxxxxx] On Behalf Of Karr, David
> > Sent: Friday, April 15, 2005 9:53 AM
> > To: aspectj-users@xxxxxxxxxxx
> > Subject: [aspectj-users] Status of using XML config,as opposed to
> > language-based annotations?
> >
> > Correct me if I'm wrong, but I believe one of the basic differences
> > between Aspectwerkz and AspectJ is that the former uses an XML file for
> > configuring the pointcuts and aspects, but the latter uses
> > language-based annotations for specifying the pointcuts.  I believe the
> > fact that Aspectwerkz uses an XML file for pointcut specifications helps
> > to facilitate its ability to do load-time weaving of third-party libs.
> >
> > As AspectJ moves forward with integrating features of Aspectwerkz, will
> > it have the ability to specify the aspect integration entirely in an XML
> > file, without requiring language extensions?  I'm hoping I can add
> > aspects to pointcuts using pure Java code.  Will this be feasible with
> > the final AspectJ 5.0?