Re: [aspectj-users] Constructor ITD question: introduce no-arg ctor ins

[Matthew Adams <matthew@xxxxxxxxxxxxxxx>]

Hi Simone,

I'm aware of the fact that you can't use type patterns when declaring
an ITD.  I had already tried injecting a no-arg constructor to a
marker interface and using declare parents, and that didn't work.  The
aspect I tried is:

import javax.persistence.Entity;
public aspect NoArgConstructorMixin {
	public static interface HasNoArgConstructor {}
	declare parents : ((@Entity *)) implements HasNoArgConstructor;
	public HasNoArgConstructor.new() {}
}

The ajc compiler error is:
error at public HasNoArgConstructor.new() {}
       ^^^^^^^^^^^^^^^^^^^^^^^
C:\dev\svnrepos\itsj\linx2\trunk\case\case-model\src\main\aspect\org\piercecountywa\linx\casemanagement\model\aspects\NoArgConstructorMixin.aj:11:0::0
can't define constructors on interfaces

This is what I expect -- constructors don't make sense on interfaces.
Am I doing something wrong in the definition of the aspect?

I've also confirmed that it's not an OpenJPA enhancer error, because
the field initialization code is not placed into the introduced class;
it's in the aspect.  If ajc were to introduce the field **with its
initialization code**, it would work.  If we manually add a no-arg
constructor then decompile the class, we can see ajc's post-construct
after advice that initialized the introduced fields.

Thanks,
Matthew

On Wed, Oct 28, 2009 at 6:18 AM, Simone Gianni <simoneg@xxxxxxxxxx> wrote:
> Hi Matthew,
>
>
> Matthew Adams wrote:
>>
>> =====================
>> // DOES NOT COMPILE
>> public aspect NoArgConstructorMixin {
>>    public ((@Entity *) && !hasmethod(* new())).new() { // can't
>> introduce constructors with this syntax
>>        // how do I ensure fields are initialized in here?  call super()?
>>    }
>> }
>> =====================
>>
>
> you cannot use type patterns when declaring an ITD. The syntax of ITD
> expects a simple type, not a pattern.
>
> So you can write :
>
> public String SomeClass.toString() { ... }
>
> But you cannot write :
>
> public String ((@Entity *)).toString() { ... }
>
> Instead you have to do as you have already done with the Intro interface :
> declare an empty marker interface, then tell AspectJ to inject methods to
> that interface, then use declare parents to place the interface using a type
> pattern.
>
> You should be able to declare also constructors this way.
>
> I'm also using ApsectJ + OpenJPA enhancer, and I'm not facing the problem
> this problem, but probably I don't have fields initialized calling a static
> method. Since OpenJPA enhances the class AFTER ajc (for me too), it should
> see all the fields and methods that ajc has added to the entity classes
> correctly (it surely does for property).
>
> If the OpenJPA introduced constructor does not take into account the fields
> added by AspectJ then maybe you're hitting a bug in the OpenJPA enhancer.
>
> Hope this helps,
> Simone
>
> --
> Simone Gianni            CEO Semeru s.r.l.           Apache Committer
> http://www.simonegianni.it/
>
> _______________________________________________
> aspectj-users mailing list
> aspectj-users@xxxxxxxxxxx
> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>



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