Re: [aspectj-users] suspicious super call interception

[Kristof Jozsa <kristof.jozsa@xxxxxxxxx>]

Ok I see where the misunderstanding came from - sorry I wasn't clear enough on the first run. Thanks for your help and the explanation, I'll remember that limitation in the future.

rgds,
K

On Mon, Sep 28, 2009 at 9:45 PM, Andy Clement <andrew.clement@xxxxxxxxx> wrote:

Hi,

I wrote my sample because you mentioned this:

> To my best knowledge, the two calls at (1) and (2) does the very same in Java,

and the sample showed that super.X() and X() can potentially do
different things depending on the hierarchy and what is overridden
where, so they are not always equivalent to each other (I know they
happen to do the same in your hierarchy, but not in every hierarchy) -
and perhaps that gives some insight as to why AspectJ is treating them
differently.

But, as I also mentioned in my email, there are no join points for
super calls, so you cannot match that call. ÂThe best you can do right
now is use execution() instead - if the code containing the method is
accessible to the weaver (I suspect you'll say it isnt....).
The topic of whether to change weaver behaviour and allow interception
of super calls has come up a few times on the list but it has never
generated enough interest to lead to a real work item and get the
weaver changed.

cheers,

Andy

2009/9/28 Kristof Jozsa <kristof.jozsa@xxxxxxxxx>:
> Hi Andy,
>
> I think your sample is about something else. The code I pasted has a child
> class which in fact doesn't hold the method getting called, therefore
> methodcall() and super.methodcall() results in an identical behaviour just
> one of them gets weaved while the other doesn't.
>
> My target was to simply create a pointcut which can intercept childclasses
> of javax.xml.ws.Service calling their parent's getPort() method. See my
> original code:
>
> pointcut wsGetPortCall() :
> ÂÂÂ ÂÂÂ call(Object javax.xml.ws.Service+.getPort(..));
>
> but this in fact behaved a bit differently as expected as it missed the
> cases where other programmers typed super.getPort() and not simply getPort()
> in their code (and they did not had a getPort() body overwriting the
> superclass' one). This was the barebone example code which demonstrates the
> exact problem I'm having:
>
> new Service(null, null) {
> ÂÂÂ @SuppressWarnings("unused")
> ÂÂÂ public void boo() {
> ÂÂÂ ÂÂÂ super.getPort(null);ÂÂÂ // (1)
> ÂÂÂ ÂÂÂ getPort(null);ÂÂÂÂÂÂÂÂÂÂÂÂ // (2)
> ÂÂÂ }
> };
>
> I hope it makes more sense now. My question is how to accomplish my original
> goal? Is it possible?
>
> thanks,
> K
>
>
>
> On Mon, Sep 28, 2009 at 5:26 PM, Andy Clement <andrew.clement@xxxxxxxxx>
> wrote:
>>
>> public class A {
>> Âpublic static void main(String []argv) {
>> Â ÂB b = new B();
>> Â Âb.run();
>> Â}
>> }
>>
>>
>> class Base {
>> Âpublic void getPort() {
>> Â ÂSystem.out.println("Base.getPort()");
>> Â}
>> }
>>
>> class B extends Base {
>> Âpublic void run() {
>> Â Âsuper.getPort();
>> Â ÂgetPort();
>> Â}
>> Âpublic void getPort() {
>> Â ÂSystem.out.println("B.getPort()");
>> Â}
>> }
>>
>> javac A.java
>> java A
>> Base.getPort()
>> B.getPort()
>>
>> they can do different things. ÂIf your question is why your advice
>> didn't match, it is because super calls are not join points. ÂAnd that
>> is probably a hangover from the old days of source weaving I think,
>> which has just never been revisited.
>>
>> Andy
>>
>>
>> 2009/9/28 Kristof Jozsa <kristof.jozsa@xxxxxxxxx>:
>> > Sample code:
>> >
>> > public aspect WSPortFixerInterceptor {
>> > ÂÂÂ pointcut wsGetPortCall() :
>> > ÂÂÂ ÂÂÂ call(Object javax.xml.ws.Service+.getPort(..));
>> >
>> > ÂÂÂ Object around() : wsGetPortCall() {
>> > ÂÂÂ ÂÂÂ return
>> > WsClientTool.getInstance().fixWebServicePort(proceed());ÂÂ //
>> > never mind this line
>> > ÂÂÂ }
>> >
>> >
>> > ÂÂÂ /** private inner class to verify correct interception */
>> > ÂÂÂ @SuppressWarnings("unused")
>> > ÂÂÂ private static class TestFixer {
>> > ÂÂÂ ÂÂÂ {
>> > ÂÂÂ ÂÂÂ ÂÂÂ new Service(null, null) {
>> >
>> > ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ @SuppressWarnings("unused")
>> > ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ public void boo() {
>> > ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ super.getPort(null);ÂÂÂ // (1)
>> > ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ getPort(null);ÂÂÂÂÂÂÂÂÂÂÂÂ // (2)
>> > ÂÂÂ ÂÂÂ ÂÂÂ ÂÂÂ }
>> > ÂÂÂ ÂÂÂ ÂÂÂ };
>> > ÂÂÂ ÂÂÂ }
>> > ÂÂÂ }
>> > }
>> >
>> > To my best knowledge, the two calls at (1) and (2) does the very same in
>> > Java, but appearently (2) gets intercepted by this aspect and (1) does
>> > not..
>> > what's the explanation for this behaviour?
>> >
>> > thanks,
>> > K
>> >
>> > _______________________________________________
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>> > https://dev.eclipse.org/mailman/listinfo/aspectj-users
>> >
>> >
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