Re: [aspectj-users] Aspects in dependent projects in Eclipse

["Wes Isberg" <wes@xxxxxxxxxxxxxx>]

Hi Matthias-

You asked how to develop aspects for a separate Java project in Eclipse.

(We really need to get IDE support in AJDT for simple inter-project 
dependencies like this, or at least document the approaches below
in the AJDT user guide.)

Given Eclipse Java project P and AspectJ project A, try one of these:

(A) Create a source folder in A that links to sources in P.  
Also add all dependencies of P to A. 

(B) Like (A), but instead of linked source folders, set up the 
inpath of A to include the output directory of P.

(C) Set up another AspectJ project, AP, which either
(1) puts A output dir on the aspectpath and P output directory
    on the inpath; or
(2) uses linked source folders to include A and P sources
    (along with other aspects in AP).

(D) Have no relationship between A and P, but have a run 
configuration that does load-time weaving.  There are different
ways to do this, depending on your VM.  See the aj.bat script,
or set the following properties:
 java.system.class.loader=org.aspectj.weaver.WeavingURLClassLoader
 aj.class.path=...
 aj.aspect.path=...

(D) only works if you don't need P to compile or weave A, and
is usable only if you don't need any IDE support across A and P.

Factors to consider:

- For any of these, the run configuation needs to be set up from
the master project (e.g., A in (A) or AP in (C)).  As you noted,
a run configuration from P would not include the aspects.

- If you want A to target more than P, then (A) and (B) don't work.

- When using binary input for inpath or aspectpath, AJDT might 
not navigate to join points in associated sources. (I haven't
tried this in a while.)

- When using linked source folders, the linked source essentially
gets compiled again for each link.  Sometimes I close the source
project and just work in the master/linking project, including
editing linked sources.

- If you know that the code in P is not changing, it's usually
faster to use binary input than source input.  In incremental
mode, if a file doesn't change it's not recompiled, so there
should be no difference -- except that in AspectJ, when an aspect
changes, all files are recompiled, and you pay a penalty for
using source rather than .class files.

I personally tend to work with linked source folders, because
I tend to be changing both A and P at the same time.  So I use
(A) normally, or (C)(2) if I have a standard set of aspects
to apply along with other aspects to another Java project.

Hope this helps.  

Wes

> ------------Original Message------------
> From: Matthias Orgler <Matthias@xxxxxxxxx>
> To: aspectj-users@xxxxxxxxxxx
> Date: Wed, Mar-2-2005 11:32 AM
> Subject: [aspectj-users] Aspects in dependent projects in Eclipse
>
> Hi,
> 
> I'm new to AspectJ and plan to do the following task:
> 
> 1) I have an existing Eclipse project (regular, i.e. NOT AspectJ), 
> which 
> I want to modify without touching it
> 2) I created a new AspectJ project and made it dependent on the first 
> one
> 3) I created a join point for a method in the first project
> 
> Here's the problem:
> 
> The AJDT outline browser shows the join point and advice, but it 
> doesn't 
> resolve the target of the join point in the first project. When I run 
> the first project, it is obviously not aware of AspectJ (since it's a 
> regular java project) and so ignores my advices.
> 
> Question:
> 
> How can I create join points for an existing Eclipse project without 
> modifying this original project?
> 
> Thanks for your help,
> 
> Matthias
> 
> -- 
> Matthias Orgler
> 
> Detecon Inc.
> 400 S. El Camino Real, Suite 500
> San Mateo, CA 94402
> 
> Phone: +1 (650) 401 5212
> Mobile: +1 (650) 430 7533
> Skype: callto://morgler
> Email: Matthias@xxxxxxxxx
> 
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