[Springframework-developer] Spring/AspectJ integration

[Rod J. <rod...@in...>]

All

I did a lot of work over the weekend on integrating Spring/AspectJ. After
the factory method IoC enhancement (which was motivated largely by AspectJ
integration, although it's otherwise useful), this hasn't required more
changes to the implementation of Spring: just experimentation with how
things work out in practice.

The fruit of this effort is in the new "samples" module, under the aspectj
directory.

This is an Eclipse AspectJ project, with two sub-projects: teacher and bank.

Teacher is based on Adrian Colyer's girl/boy/teacher example, which he
featured on his blog shortly after TSS Symposium. Thanks to Adrian for
solving the basic problem in Spring/AspectJ integration: how to configure
aspects using Dependency Injection. (Note btw the use of the "depends-on"
attribute to ensure that an aspect is configured before it's used. The
special aspect initialization bean Adrian's code used is not required.)

Bank is a new example, showing a few scenarios relevant to enterprise usage.
It's based around a Bank interface managing fine-grained Account objects. It
uses AspectJ to advise those objects, with aspects configured using Spring
DI. Advising fine-grained objects is a problem that proxy-based solutions
such as Spring's own AOP framework are not well suited to addressing.
AspectJ is perfect here.

I'm currently working on some more esoteric features, such as getting Spring
to configure "perthis" aspects, but the essential Spring/AspectJ integration
is in place. I'll be adding to and polishing the code in the samples module
over the next few weeks, with the aim of releasing it as a separate sample
download some time in July.

I think that integration with AspectJ is going to benefit many Spring users.
This is going to be one of the major new features of Spring 1.1. I encourage
users interested in AOP to check it out, and feed back comments or
contributions.

Btw there is no conflict with using AspectJ and Spring's own AOP framework
in the same application.

Currently there are no build scripts in the aspectj sample--it relies on
Eclipse. Any contribution of a build script will be gratefully received!

Rgds
Rod