Re: [aspectj-dev] Declaring final inter-type fields/methods/etc

[Keven Ring <keven@xxxxxxxxx>]

Andrew Clement wrote:

> Hi Keven,
>
> I was going through the AspectJ bugs earlier on today, and I believe 
> there is one that
> covers what you are describing:
>
> Bugzilla Bug 52105: final static constant fields not treated as such
>
> Here is a direct link, there is quite a bit of discussion in the bug 
> report:
>
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=52105
>
> Basically we don't make them final because they get initialized in the 
> aspect rather than
> the type upon which you make the declaration.  If they were final we 
> wouldn't be able to do this.
>
> The bug is still open and we haven't decided how to resolve it yet ...
>
> Andy.
Thanks.  This appears to be the exact situation I am in.

You mention that they get initialized in the aspect.  Uninitialized 
<static> final variables can be initialized in a static constructor.  
This means that I can do the following (for instance):

public class MyClass {
 public static final int FOOBAR;

 static {
    FOOBAR = 10;
 }
}

public aspect MyAspect {
   pointcut si(): staticinitialization(MyClass);

 before(): si() {
   System.out.println(MyClass.FOOBAR);
 }

 after(): si() {
   System.out.println(MyClass.FOOBAR);
 }
}

This results in the following output:
0
10

Does this suggest that a possible future solution would be to add before 
advice to do the initialization and weaving of final variables?

As far as the use case (suggested by Matthew Webster), it goes back to 
my question a couple of months ago regarding dynamically defining fields 
such that the fields can be used (specifically) as a branch of a switch 
statement.  As Gregor Kiczales pointed out in that thread, a parser 
which created an aspect that was then weaved would be a possible 
solution.  Public static final fields (in this case) are (IMO) the 
cleanest solution.  However, they are by no means the only solution.

Thanks again!

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