...and here you go:
public aspect DontExtend {
public static class Anything {}
declare parents :
!Enum+ &&
!Annotation+ &&
whatever..* // classes to restrict
extends Anything;
}
This yields the following compilation error for me:
[ERROR] Failed to execute goal
org.codehaus.mojo:aspectj-maven-plugin:1.4:compile (default) on
project app-domain: Compiler errors:
[ERROR] error at declare parents :
[ERROR] !Enum+ &&
[ERROR] !Annotation+ &&
[ERROR] app.domain.model..*
[ERROR] extends Anything;
[ERROR]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[ERROR]
/Users/matthew/Documents/test/production/app/domain/src/main/aspect/app/domain/aspect/horizontal/DontExtend.aj:12:0::0
can only insert a class into hierarchy, but
app.domain.aspect.horizontal.DontExtend$Anything is not a subtype of
app.domain.model.Test
Works!
I was thinking also about how to force all model classes to be final.
I thought about some form of either 'declare error : !final
app.domain.model..* : "model classes must be final"' or an ITD to
introduce the final modifier. Is that possible?
-matthew
On Fri, Aug 17, 2012 at 12:45 PM, Matthew Adams <matt...@matthewadams.me> wrote:
>
> Interesting. I like all of the suggestions. I entered an issue to track
> this:
> https://bugs.eclipse.org/bugs/show_bug.cgi?id=387499
>
> Thanks!
>
>
> On Thu, Aug 16, 2012 at 3:05 PM, Andy Clement <andrew.clem...@gmail.com>
> wrote:
>>
>> I haven't spent toooo long thinking about it, but I don't think you
>> can at the moment. We don't really have the capabilities to introspect
>> the class hierarchy to that level of detail.
>>
>> Some made up syntaxes:
>>
>> If 'Object+' indicates subtypes, let's add a numeric to indicate distance:
>> declare error: within(Object+2): "Type does not directly extend
>> object"; // maybe add the type category type pattern too:
>> within(is(ClassType) && Object+2)
>> declare error: within(Object+>2): "Type does not directly extend object";
>>
>> More direct:
>> declare error within(!extends(Object)): "Type does not directly extend
>> object"; // if 'extends' is strictly looking at the declared type and
>> not the inheritance chain.
>>
>> You could probably cause an error if you tried to use declare parents
>> extends with a simple type because extends will report an error if the
>> new type doesn't have the same parent as the existing type:
>>
>> class Foo1 {}
>> class Foo2 extends ArrayList {}
>>
>> class Marker {}
>>
>> aspect X {
>> declare parents: Foo* extends Marker;
>> }
>>
>> will give an error ... but it isn't as simple as a nice message saying
>> 'type Foo2 doesn't directly extend Object.'
>>
>> cheers,
>> Andy
>>
>> On 16 August 2012 08:40, Matthew Adams <matt...@matthewadams.me> wrote:
>> > Just for fun, I was trying to think of how to use declare error to prevent
>> > the use of class inheritance in user code, but I can't think of how to do
>> > that.
>> >
>> > Basically, if you wanted to disallow the declaration of classes that extend
>> > anything other than Object, is there a "declare error" form that would
>> > work?
>> >
>> > -matthew
>> >
>> > --
>> > mailto:matt...@matthewadams.me
>> > skype:matthewadams12
>> > googletalk:matt...@matthewadams.me
>> > http://matthewadams.me
>> > http://www.linkedin.com/in/matthewadams
>> >
>> >
>> > _______________________________________________
>> > aspectj-users mailing list
>> > aspectj-users@eclipse.org
>> > https://dev.eclipse.org/mailman/listinfo/aspectj-users
>> >
>> _______________________________________________
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>
>
>
>
> --
> mailto:matt...@matthewadams.me
> skype:matthewadams12
> googletalk:matt...@matthewadams.me
> http://matthewadams.me
> http://www.linkedin.com/in/matthewadams
>
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