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Re: [aspectj-users] policy enforcement for parameterless constructor and certain field declaration
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Hi,
thanks for your time figuring them out and explaining the differences
between my trial and the correct approach - I've learnt a lot.
I think these features in aspect are really useful for building
frameworks and enforcing correct usage. I hope it gets more popular
(and more documented) in the future..
cheers,
K
On Fri, May 27, 2011 at 5:34 PM, Andy Clement <andrew.clement@xxxxxxxxx> wrote:
> Hi,
>
> ok, your first two pointcuts aren't quite right:
>
> First one:
>
> declare error: hasfield((@Injected *) *): "hit match1"; // try to
> simply match 'match1' as an @Injected field
>
> This is attempting to match when the type has a field whose type is
> marked @Injected. As far as I can see, that isn't what you want, you
> are interested in whether the field itself is annotated, not the type
> of the field. That would be simply:
>
> declare error: hasfield(@Injected * *): "hit match1"; // try to simply
> match 'match1' as an @Injected field
>
> Second one:
>
> declare error: hasfield(@Injected (!(@Managed *) *): "hit match2";
> // try to match 'match2' as injection of a not @Managed type
>
> you are just missing a parentheses
> declare error: hasfield(@Injected (!(@Managed *)) *): "hit match2";
> // try to match 'match2' as injection of a not @Managed type
>
>
> Third one, I think that is a bug related to compound type patterns.
> if you remove the within piece (and the &&) it behaves a little
> better. Feel free to raise a bugzilla for this problem.
>
> cheers
> Andy
>
> On 26 May 2011 15:10, Kristof Jozsa <kristof.jozsa@xxxxxxxxx> wrote:
>> Hi Andy,
>>
>> thanks for your detailed answer. I understand you're dealing with a
>> limited set of resources so certainly I did not want to complain about
>> the lack of docs :) Now as you say, I checked the second edition of
>> AspectJ in Action I own and it mentions the hasmember features but in
>> about 10 lines as an experimental feature.
>>
>> At last I think I've found the unit tests I you mentioned in the Tools
>> CVS here: http://dev.eclipse.org/viewcvs/viewvc.cgi/org.aspectj/modules/tests/?root=Tools_Project
>> and grepped around in them but unfortunately I still struggle with the
>> correct syntaxes of hasmember.
>>
>> Here's a test of the two use cases what I'm trying to accomplish (I
>> did turn on XhasMember both in ajdt and maven):
>>
>> public aspect HasMemberTest {
>> @Target(ElementType.FIELD)
>> @Retention(RetentionPolicy.RUNTIME)
>> public static @interface Injected {
>> }
>>
>> @Target(ElementType.TYPE)
>> @Retention(RetentionPolicy.RUNTIME)
>> public static @interface Managed {
>> }
>>
>> public static class Sample {
>> @Injected
>> private SampleManaged match1;
>>
>> @Injected
>> private String match2;
>> }
>>
>> @Managed
>> public static class SampleManaged {
>> public SampleManaged(int foo) {}
>> }
>>
>> declare error: hasfield((@Injected *) *): "hit match1"; // try to
>> simply match 'match1' as an @Injected field
>> declare error: hasfield(@Injected (!(@Managed *) *): "hit match2"; //
>> try to match 'match2' as injection of a not @Managed type
>> declare error: within(@Managed *) && !hasmethod(new()) : "no default
>> constructor"; // try to match SampleManaged non-default constructor
>> }
>>
>> where the first declare fails to match and the other two is not
>> syntaxically correct in spite of I've spent a couple of hours now
>> trying to get them right (ok, the second one looks a bit too funky for
>> me as well).
>>
>> Is type pattern matching complete with annotation usage?
>>
>> thanks,
>> K
>>
>>
>> On Thu, May 26, 2011 at 6:06 PM, Andy Clement <andrew.clement@xxxxxxxxx> wrote:
>>> Hi,
>>>
>>> On 26 May 2011 01:36, Kristof Jozsa <kristof.jozsa@xxxxxxxxx> wrote:
>>>> Hmm I wasn't yet aware of this hasmember feature. I tried to google
>>>> around and also checked my copy of Aspectj in Action but could not
>>>> find much examples.
>>>
>>> I can't recall if it was covered, but if it was it would be in the
>>> second edition (not the first) of AspectJ in action. Given that it is
>>> still an 'optional' feature, I'm not sure if Ramnivas did cover it or
>>> not.
>>>
>>>> Are there any usage details on hasfield/hasmethod somewhere? Also, is
>>>> there a unit test suite which I could check for examples? The AspectJ
>>>> source download doesn't seem to include any tests..
>>>
>>> There are numerous tests in AspectJ for this. The source for the
>>> tests is not available in zip form though, it is only in the
>>> repository. The source zips downloadable alongside the distribution
>>> are only for what is in the distribution. Searching the source I see
>>> about 30/40 tests.
>>>
>>> The feature is actually described in this bug:
>>> https://bugs.eclipse.org/bugs/show_bug.cgi?id=86818 - which you'll
>>> actually see is still open. It is still open because you have to
>>> switch on this feature with -XhasMember, it still hasn't been made
>>> 'default'. It isn't default because it still doesn't play nicely with
>>> all the other language features (basically ITDs) - until it does it
>>> will still be something to opt into.
>>>
>>> But it was only in 1.6.9 that I added the ability to use type patterns
>>> with declare warning/error:
>>> http://www.eclipse.org/aspectj/doc/released/README-169.html
>>>
>>> ---
>>> It is now possible to use a type pattern with declare warning and
>>> declare error. For example:
>>> declare warning: I+ && !hasfield(int i): "Implementations of I are
>>> expected to have a int field called i";
>>> ---
>>> I do acknowledge (and apologise that) the main docs don't cover it
>>> properly. We last had the resource to do a good docs update for 1.5.0
>>> and that was all focussed on generics/annotations/etc when AspectJ was
>>> upgraded for Java5. Since then it is basically the sequence of
>>> READMEs that detail what has happened with AspectJ.
>>>
>>> Here is one of our testcases for it:
>>> ===
>>> public aspect HasMethod {
>>>
>>> declare parents : hasmethod(* print(..)) implements Printable;
>>>
>>> public static void main(String[] args) {
>>> C c = new C();
>>> if (! (c instanceof Printable)) {
>>> throw new RuntimeException("declare parents : hasmethod failed");
>>> }
>>> }
>>> }
>>>
>>> class C {
>>> public void print() {}
>>> }
>>>
>>> interface Printable {};
>>> ===
>>>
>>> cheers
>>> Andy
>>>
>>>> On Wed, May 25, 2011 at 3:16 PM, Matthew Adams <matthew@xxxxxxxxxxxxxxx> wrote:
>>>>> For the first one, you might try using "declare error" with a type
>>>>> pattern that uses hasmember. Not sure what you mean by the second,
>>>>> but declare error with hasmember might do the trick there, too.
>>>>>
>>>>> -matthew
>>>>>
>>>>> On Sat, May 21, 2011 at 5:57 PM, Kristof Jozsa <kristof.jozsa@xxxxxxxxx> wrote:
>>>>>> I'd like to ask for help with two policy enforcement rules:
>>>>>> - enforce a class having no constructor with arguments (a default or a
>>>>>> parameterless constructor is fine)
>>>>>> - enforce an annotated field being of a certain type
>>>>>>
>>>>>> For the second one I currently enforce the get() of the field which is not
>>>>>> too bad, but would be nicer to disallow the field declaration.. if possible.
>>>>>>
>>>>>> Can anyone show me an example doing these tricks?
>>>>>>
>>>>>> Thanks a lot,
>>>>>> K
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> aspectj-users mailing list
>>>>>> aspectj-users@xxxxxxxxxxx
>>>>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> @matthewadams12
>>>>> mailto:matthew@xxxxxxxxxxxxxxx
>>>>> skype:matthewadams12
>>>>> yahoo:matthewadams
>>>>> aol:matthewadams12
>>>>> google-talk:matthewadams12@xxxxxxxxx
>>>>> msn:matthew@xxxxxxxxxxxxxxx
>>>>> http://matthewadams.me
>>>>> http://www.linkedin.com/in/matthewadams
>>>>> _______________________________________________
>>>>> aspectj-users mailing list
>>>>> aspectj-users@xxxxxxxxxxx
>>>>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>>>>>
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